Đang tải... (xem toàn văn)
Dữ liệu cổ từ có sẵn từ thành đá của tuổi Creta từ Việt Nam, Đông Dương và Nam Trung Quốc được biên soạn và xem xét trong bối cảnh kiến tạo tầm quan trọng của họ trong một hệ quy chiếu chung đối với paleopoles đồng niên ÁÂu với. Yếu tố quan trọng đóng một vai trò quan trọng trong việc xác định độ tin cậy của kết quả cổ từ để sử dụng trong các nghiên cứu kiến tạo đã được đưa vào xem xét, bao gồm các trường hợp không có bằng chứng về remagnetization, mà là một tính năng phổ biến đối với nhiều loại đá trong khu vực này. Nhìn chung, các dữ liệu cổ từ kỷ Phấn trắng từ khối Nam Trung Hoa cho thấy rằng vị trí địa lý hiện tại của khối Nam Trung Hoa đã tương đối ổn định đối với Âu Á với từ giữa kỷ Phấn Trắng và các paleomagnetically phát hiện chuyển động của một khối thạch quyển mạch lạc phải căn cứ vào các dữ liệu thu được từ đại diện các địa phương cụ thể khác nhau trên toàn khối để tách nhiều địa phương, biến dạng quy mô nhỏ hơn từ đúng chuyển động quy mô thạch quyển (dịch và hoặc xoay) của một khối kiến tạo. Phấn trắng dữ liệu cổ từ đại học đầu từ Đông DươngThiện Thái Khối tiết lộ các mẫu phức tạp của nội tấm biến dạng để đáp ứng với các va chạm Ấn ĐộEurasia. Paleomagnetically phát hiện chuyển động từ lợi nhuận của các khối kiến tạo để được giải thích chủ yếu là phản ánh chuyển của các khối lớp vỏ phía trên do gấp và đứt gãy quy trình. Cứng nhắc, luân chuyển khối thạch quyển quy mô không nhất thiết phải được hỗ trợ bởi các dữ liệu cổ từ. Kết quả cổ từ từ các khu vực phía đông và phía nam của hệ thống đứt gãy Sông Hồng cho rằng hệ thống lỗi transcurrent lớn này đã có một lịch sử trượt phức tạp thông qua nhiều của Kainozoi và nó không phân ranh giới hoàn toàn không đáng kể và xoay xoay các bộ phận của vỏ trái đất trong lĩnh vực này. Tuy nhiên, hầu hết các kết quả cổ từ từ các khu vực phía đông và phía nam của hệ thống đứt gãy Sông Hồng ở vĩ độ của tỉnh Vân Nam là phù hợp với một rất khiêm tốn (khoảng 800 km + ) phần phía nam, nhưng paleomagnetically phân giải của dịch vĩ độ. Theo đó, do khó khăn trong việc tách thạch quyển quy mô chuyển động tấm thực tế từ những người tương đối mỏng, khối vỏ trên, chúng tôi chủ trương hết sức thận trọng trong việc giải thích dữ liệu cổ từ từ các khu vực như Đông Dương, nơi khối tương tác và biến dạng mạnh mẽ được biết là đã xảy ra. Thượng Chí Cung
G Model GEOD-1103; No of Pages 11 ARTICLE IN PRESS Journal of Geodynamics xxx (2013) xxx–xxx Contents lists available at SciVerse ScienceDirect Journal of Geodynamics journal homepage: http://www.elsevier.com/locate/jog A review of the paleomagnetic data from Cretaceous to lower Tertiary rocks from Vietnam, Indochina and South China, and their implications for Cenozoic tectonism in Vietnam and adjacent areas Cung Thuo ng Chí a,∗ , John W Geissman b,1 a b Institute of Geological Sciences, Vietnam Academy of Science & Technology 84 Chua Lang Street, Dong Da Dist., Hanoi, Viet Nam Department of Earth and Planetary Sciences, MSC 03 2040, University of New Mexico, Albuquerque, NM 87131-0001, United States a r t i c l e i n f o Article history: Received 22 July 2010 Received in revised form 19 November 2011 Accepted 22 November 2011 Available online xxx Keywords: Paleomagnetism Tectonics Cretaceous Vietnam Indochina South China Extrusion a b s t r a c t Available paleomagnetic data from rock formations of Cretaceous age from Vietnam, Indochina and South China are compiled and reviewed in the context of their tectonic importance in a common reference frame with respect to Eurasia’s coeval paleopoles Key factors that play an important role in determining the reliability of a paleomagnetic result for utilization in tectonic studies have been taken into consideration and include the absence of evidence of remagnetization, which is a feature common to many rocks in this region Overall, the Cretaceous paleomagnetic data from the South China Block show that the present geographic position of the South China Block has been relatively stable with respect to Eurasia since the mid-Cretaceous and that the paleomagnetically detected motion of a coherent lithospheric block must be based on the representative data obtained from different specific localities across the block in order to separate more localized, smaller scale deformation from true lithosphere scale motion (translation and/or rotation) of a tectonic block Cretaceous to early Tertiary paleomagnetic data from the Indochina–Shan Thai Block reveal complex patterns of intra-plate deformation in response to the India–Eurasia collision Paleomagnetically detected motions from the margins of tectonic blocks are interpreted to mainly reflect displacement of upper crustal blocks due to folding and faulting processes Rigid, lithosphere scale block rotation is not necessarily supported by the paleomagnetic data The paleomagnetic results from areas east and south of the Red River fault system suggest that this major transcurrent fault system has had a complicated slip history through much of the Cenozoic and that it does not demarcate completely non-rotated and significantly rotated parts of the crust in this area However, most paleomagnetic results from areas east and south of the Red River fault system at the latitude of Yunnan Province are consistent with a very modest (about 800 km+−), yet paleomagnetically resolvable southward component of latitudinal translation Accordingly, given the difficulty in separating actual lithosphere-scale plate motions from those of relatively thin, upper crustal blocks, we advocate extreme caution in interpreting paleomagnetic data from regions such as Indochina where block interaction and strong deformation are known to have occurred © 2011 Elsevier Ltd All rights reserved Introduction The tectonic history of the Southeast Asia region has attracted the attention of numerous geoscientists for over a century Active tectonic-geodynamic processes have affected the region in a ∗ Corresponding author Tel.: +84 0913 222 102; fax: +84 37754797 E-mail addresses: chicung@gmail.com (T.C Cung), geissman@utdallas.edu (J.W Geissman) Now at: Department of Geosciences, The University of Texas at Dallas, ROC 21, 800 West Campbell Road, Richardson, TX 75080-3021, United States Tel: +1 972 883 2454; fax: +1 972 883 2537 prolonged and complicated fashion These include the subduction of the Indo-Australian plate under the Eurasia plate along the Indonesia arc; the India–Eurasia collision and different intra-plate deformation processes associated with the formation and growth of the Tibetan Plateau The Southeast Asian region is considered a natural laboratory for active tectonic and geodynamic processes, and thus can be used as an analog for studying more ancient tectonic processes There are two general schools of thought regarding the effects of the collision between India and Eurasia on the subsequent tectonic history of eastern and southeast Asia Proponents of extrusion tectonics suggest that convergence between the Indian subcontinent and the Eurasian plate was mainly accommodated by east–southeast directed translation and rotation of 0264-3707/$ – see front matter © 2011 Elsevier Ltd All rights reserved doi:10.1016/j.jog.2011.11.008 Please cite this article in press as: Cung, T.C., Geissman, J.W., A review of the paleomagnetic data from Cretaceous to lower Tertiary rocks from Vietnam, Indochina and South China, and their implications for Cenozoic tectonism in Vietnam and adjacent areas J Geodyn (2013), doi:10.1016/j.jog.2011.11.008 G Model GEOD-1103; No of Pages 11 ARTICLE IN PRESS T.C Cung, J.W Geissman / Journal of Geodynamics xxx (2013) xxx–xxx Fig Generalized tectonic framework map of Southeast Asia, modified from Leloup et al (2001) and Takemoto et al (2005) Arrows adjacent to several major structures show overall sense of shear prior to ∼16 Ma along these structures large-scale, discrete continental lithospheric blocks such as ‘Sundaland’ (i.e Indochina, Shan-Thai, the southwest East Vietnam Sea, and southwest Borneo), South China, and Tibet along major leftlateral strike-slip faults (Tapponnier et al., 1982, 1986; Peltzer and Tapponnier, 1988; Replumaz and Tapponnier, 2003) (Fig 1) In contrast, other workers argue that crustal shortening and thickening in the Himalaya and Tibet is the principal mechanism for accommodating this collision (Dewey et al., 1989; England and Houseman, 1989; England and Molnar, 1990) One major consequence predicted by both models, however, is a large-magnitude clockwise rotation of Sundaland, which behaved either as a rigid lithospheric block (a basic tenet of the extrusion model) or as a series of uppercrustal blocks that were translated southeastward along laterally continuous, north–south–trending dextral shear zones and rotated in a clockwise sense (as in crustal shortening models) Over the past few decades, paleomagnetic results from rocks of different ages and origins from the Southeast Asian region have increased both in quantity and quality, and the data obtained contribute to elucidating the tectonic history of this region over time, by providing increasingly accurate paleogeographic reconstructions of lithosphere-scale and smaller blocks that were welded together as microcontinents to form the Eurasian continent (Fig 2) However, the interpretation of paleomagnetic results from an actively deforming region such as Southeast Asia is not straightforward, because early acquired, essentially primary magnetizations may be modified by subsequent tectonic effects, involving enhanced fluid migration, increased burial and thus enhanced temperatures, penetrative deformation, as well as other processes (Lowrie et al., 1986; McCabe and Elmore, 1989; Fuller et al., 1991; Gillett and Geissman, 1993; Pares et al., 1999; Van der Voo and Torsvik, 2011) Paleomagnetically detected rotations, as documented by discrepancies or discordances in declination between observed and expected (or “reference”) declinations may sometimes reflect spatially localized components of deformation related to shear zones (Ron et al., 1984; Jackson and Molnar, 1990), differential shortening within thrust sheets (Stamatakos and Hirt, 1994; Roperch et al., 2000; Sussman et al., 2004; Pueyo et al., 2004), or arc related deformation (MacDonald, 1980; Minyuk and Stone, 2009) Therefore, rigid body, internally coherent rotations of plates, or microplates, cannot always be assumed on the basis of the data available This paper synthesizes the available paleomagnetic data from Cretaceous to Paleogene continental red bed formations from the Indochina and South China regions obtained in several studies by different researchers and evaluates their tectonic importance, especially paleomagnetically detected deformation (specifically rotation and translation) of crustal elements that is likely related to the India–Eurasia collision during the Cenozoic Space does not allow us to focus attention on the details of the accuracy and reliability of each specific paleomagnetic data set; rather, we concentrate on the tectonic interpretation of these data, and consider such factors as the origin and nature of magnetization characteristic of the rocks examined (e.g., primary or secondary, i.e., the extent of possible remagnetization), the age of the rock formation, and the effects that tectonic deformation may have played in defining the tectonic importance The relative rotation and translation of any structural block or domain that have been identified on the basis of paleomagnetic directions from rocks located within that block are determined by comparing the observed directions with the coeval expected Please cite this article in press as: Cung, T.C., Geissman, J.W., A review of the paleomagnetic data from Cretaceous to lower Tertiary rocks from Vietnam, Indochina and South China, and their implications for Cenozoic tectonism in Vietnam and adjacent areas J Geodyn (2013), doi:10.1016/j.jog.2011.11.008 ARTICLE IN PRESS G Model GEOD-1103; No of Pages 11 T.C Cung, J.W Geissman / Journal of Geodynamics xxx (2013) xxx–xxx Table Apparent Polar Wander Path for Eurasia derived by Besse and Courtillot (1991) Age (Ma) 10 20 30 40 50 60 70 80 90 100 Mean Eocene poles Mean K2 poles Mean K1 poles Mean K poles Mean J3–K poles Mean J3–K1 poles (◦ N) (◦ E) A95 Age (Ma) 84.1 82.3 81.0 80.2 77.9 78.5 77.2 76.2 76.7 76.7 79.8 77.2 149.1 147.6 132.8 145.4 149.0 178.7 192.4 198.9 200.1 197.1 143.1 193.9 2.3 3.2 2.7 3.8 4.3 3.9 4.1 3.4 3.5 5.4 3.3 2.0 110 120 130 140 150 160 170 180 190 200 75.9 75.4 196.0 186.6 (◦ N) 2.5 3.6 73.3 74.8 75.2 71.6 70.0 68.8 63.3 64.2 66.7 67.3 (◦ E) 206.5 210.9 205.8 173.0 157.8 154.9 120.7 116.7 109.0 111.6 A95 74.3 directions of a reference block or continent derived from an Apparent Polar Wander Path (APWP) that, ideally, is well determined for the appropriate geologic time interval in question Besse and Courtillot (1991, 2002) have derived synthetic APWPs for the Eurasia continent from 200 Ma to present with considerably high precision In addition, several studies have contributed to the independent development of an APWP for the South China block itself (e.g., Enkin et al., 1992; Chen et al., 1993; Hankard et al., 2005; Sun et al., 2006; Zhu et al., 2006; Tsuneki et al., 2009), therefore the paleomagnetic data from rocks of the Indochina and South China blocks discussed in this paper will be compared with the expected Note 5.1 4.1 5.0 10.4 6.7 6.0 3.0 2.7 3.9 6.7 198.1 6.0 73.7 181.8 6.7 30–50 Ma poles 60–100 Ma poles 110–140 Ma poles 60–140 Ma poles 60–160 Ma poles 110–160 Ma poles directions calculated from this APWP for certain geologic time periods (Table 1) to evaluate their tectonic significance Cretaceous paleomagnetic results of the South China Block According to Hsu et al (1988), the South China Block consists of two micro-continents—the Yangtze Craton in the northwest and the Hoa Nam Block in the southeast (Fig 1) These two micro-continents were welded together during subduction of the Fig Simplified tectonic framework digital elevation map of the Indochina and South China regions and the observed declinations of selected Cretaceous rock formations compared with expected declination values Please cite this article in press as: Cung, T.C., Geissman, J.W., A review of the paleomagnetic data from Cretaceous to lower Tertiary rocks from Vietnam, Indochina and South China, and their implications for Cenozoic tectonism in Vietnam and adjacent areas J Geodyn (2013), doi:10.1016/j.jog.2011.11.008 ARTICLE IN PRESS G Model GEOD-1103; No of Pages 11 40 30 20 Mean, Late Cretaceous (K2) poles 10 -10 -20 19 20 21 22 23 24 25 27 29 31 32 Mean, Early Cretaceous (K1) poles Mean, Cretaceous poles -30 -40 -50 Locality Latitude, o N Fig Relative rotation of elements of South China tectonic block, as a function of latitude of the sampling area, with respect to Eurasia The stars represent the relative rotation of South China Block calculated from the mean of paleomagnetic poles for the Early Cretaceous, the Late Cretaceous, and the entire Cretaceous Period Vertical bars represent the uncertainty of each result, as represented by ˛95 values paleo-Pacific plate under the Eurasia plate in late Mesozoic time, along the Jiangnan suture zone, which exposes of Mesoproterozoic and Neoproterozoic low-grade metamorphic rocks Xu (1993), however, suggests that the entire eastern part of the Chinese landmass was dominated by a Mesozoic sinistral shear system The Xu (1993) hypothesis is supported by isotopic and paleomagnetic data from Jurassic and Cretaceous intrusions that are widely exposed in the southeast part of the South China Block (Gilder et al., 1996) There is general consensus that by the Late Jurassic the South China Block was already accreted to the North China Block along the Qinling suture belt, forming the stable Eurasia continent Since the early 1980s, paleomagnetic studies have been carried out on Mesozoic and Cenozoic rock formations in China, and these data have facilitated the construction of overall well-defined Apparent Polar Wander Paths (APWP) for the South China and North China blocks from the Late Permian to the present A general comparison of these APWPs with the APWP for the Eurasian continent shows that, since the Cretaceous, the South China and North China blocks have remained relatively stable with respect to the Eurasia plate (Enkin et al., 1992) The India–Eurasia collision during the Cenozoic has not significantly distorted the South China and North China blocks relative to one another and to Eurasia (Enkin et al., 1992; Chen et al., 1993) Paleomagnetic data from Cretaceous rock formations of the South China Block (listed in Table 2) show that, among 23 studies at generally separate localities, only six provide evidence for localities affected by a combination of the relative rotation and latitudinal translation, and these data mainly come from Upper Cretaceous to Eocene continental red beds For six other localities, only relative rotation has been found and two other sites show only latitudinal translation The relative rotation and latitudinal translation data are summarized in Figs and A comparison of Early Cretaceous, Late Cretaceous and overall Cretaceous mean paleopoles of the South China Block to the corresponding paleopoles of the Eurasia continent shows no significant rotation nor latitudinal translation of the South China Block overall relative to the Eurasia continent This further confirms the conclusion of previous workers (e.g., Enkin et al., 1992; Chen et al., 1993; Hankard et al., 2005; Sun et al., 2006; Zhu et al., 2006) We interpret the relative rotation and translation that is implied by data from some localities to reflect local deformation of the upper crust, rather than motion of the entire lithospheric block This interpretation appears to be consistent with the observation that, at least for some localities, larger magnitudes of rotation have been suggested in younger rocks (e.g., Upper Cretaceous to Eocene strata), yet older, underlying rock formations have been less deformed by 30 (southward) 50 25 20 Mean, Late Cretaceous (K2) poles 15 Mean, Early Cretaceous (K1) poles 10 (northward) Rotation Magnitude, in degrees (counterclockwise) (clockwise) 60 Latitudinal Translation, in degrees T.C Cung, J.W Geissman / Journal of Geodynamics xxx (2013) xxx–xxx 98 100 104 106 108 -5 -10 110 112 114 116 118 120 Mean, Cretaceous poles -15 -20 -25 Locality Longitude, o E Fig Latitudinal translation of elements of the South China block as a function of longitude of the sampling area with respect to Eurasia The stars represent the relative translation, in degrees, of parts of the South China Block calculated from the mean of paleomagnetic poles for the Early Cretaceous, the Late Cretaceous, and the entire Cretaceous Period Vertical bars represent the uncertainty of each result, as represented by ˛95 values vertical axis rotation There are alternative explanations for such seemingly disparate data sets Older rocks could have been systematically remagnetized at a time younger than the age of overlying rocks preserving primary magnetizations that imply rotations An accurate paleomagnetic assessment of the displacement of a large-scale lithospheric block should, in principle, be based on data from several well-distributed study localities, as results from deformed or deforming areas, typically at the margin of cratonic block, may likely be unrepresentative of the stable interior (e.g., Van der Voo, 1993) Data from areas that have potentially been affected by more local scale tectonism must be considered with great caution when considering their incorporation into a grand mean paleomagnetic pole determination for a craton Furthermore, the age of the rocks examined, as well as the age of the magnetization(s) that are characteristic of the rocks examined must be known for the most robust comparisons with well-dated reference paleomagnetic poles Finally, as more and more studies are demonstrating, the effects of sediment compaction on the inclination of the remanence preserved in sedimentary rocks during what are typically prolonged and complicated diagenetic processes can be significant (refs) Inclination flattening factors (f), with f being the ratio of tan (Io)/tan (If), where Io is the observed inclination and If is the decompacted or deflattened inclination, can be approximated using both laboratory-based approaches (e.g., Bilardello and Kodama, 2009, 2010) and one involving examination of the elongation bias in observed paleomagnetic vectors relative to an expected long-term geocentric axial dipole field model (Tauxe and Kent, 2004) For red beds, for example, f values typically vary from about 0.78 (e.g., Donohoo-Hurley, 2011; Donohoo-Hurley et al., in preparation) to about 0.52 (e.g., Kent and Olsen, 2008) Not all “reference” paleomagnetic poles that are used in the present overview, or any similar assessment, either include only those data from sedimentary rocks that have been adequately corrected for inclination shallowing or are based only on data from igneous rocks (unaffected by inclination shallowing) Consequently, inferences based on the inclinations of paleomagnetic data from sedimentary rocks that we discuss below must be treated with caution, as it is likely that current estimates of latitudinal translation may be in greater error than that simply based on the estimated dispersion of the population of data used to determine a mean inclination Cretaceous paleomagnetic results from Vietnam Since 1992, several paleomagnetic studies have been carried out by the first author of this contribution, as well as others, on different Please cite this article in press as: Cung, T.C., Geissman, J.W., A review of the paleomagnetic data from Cretaceous to lower Tertiary rocks from Vietnam, Indochina and South China, and their implications for Cenozoic tectonism in Vietnam and adjacent areas J Geodyn (2013), doi:10.1016/j.jog.2011.11.008 ARTICLE IN PRESS G Model GEOD-1103; No of Pages 11 T.C Cung, J.W Geissman / Journal of Geodynamics xxx (2013) xxx–xxx Table Cretaceous–Eocene paleomagnetic results of the South China block N Location (◦ N) South China block 10 11 12 13 14 15 16 17 18 19 20 21 22 23 25.7 26.1 25.7 25.9 25.0 26.0 23.1 24.4 30.0 32.0 30.8 25.0 30.1 22.2 30.0 18.9 22.7 26.0 26.5 26.8 27.9 27.9 29.7 Mean K1 poles (13–23): Mean K2 poles (3–11): Mean K poles (3–23): Age (Ma) (◦ E) 101.3 101.7 102.1 101.8 116.4 117.3 113.3 112.3 102.9 119.0 118.2 101.5 103.0 114.2 102.9 109.4 108.7 117.3 102.4 102.5 102.3 102.3 120.3 Observed VGP (◦ N) E E K2–E K2–E K2 K2 K2 K2 K2 K2 K2 K K J3–K K1 K1 K1 K1 K1 K1 K1 K1 K1 (◦ E) Expected VGP (◦ N) A95 Rotation (◦ E) R± Translation Significance Reference (13) (13) (14) (14) (4) (2) (2) (15) (9) (12) (16) (3) (11) (1) (10) (17) (2) (5) (6) (6) (7) (13) (8) ± R 72.3 70.1 61.8 65.6 67.9 65.1 56.2 66.0 72.8 76.3 83.8 49.2 76.3 78.2 74.5 83.2 86.5 66.9 81.5 69.0 77.4 85.2 77.1 218.4 224.6 192.2 203.0 186.2 207.2 211.5 221.5 241.1 172.6 200.3 178.0 274.5 171.9 229.0 143.0 26.4 221.4 220.9 204.6 196.2 241.7 227.6 4.5 4.9 10.5 2.6 9.2 5.0 3.9 3.4 6.6 10.3 14.6 11.4 11.1 10.6 4.0 9.8 10.0 5.4 7.1 4.3 14.5 3.5 5.5 79.8 79.8 77.2 77.2 77.2 77.2 77.2 77.2 77.2 77.2 77.2 75.9 75.9 75.4 74.3 74.3 74.3 74.3 74.3 74.3 74.3 74.3 74.3 143.1 143.1 193.9 193.9 193.9 193.9 193.9 193.9 193.9 193.9 193.9 196.0 196.0 186.6 198.1 198.1 198.1 198.1 198.1 198.1 198.1 198.1 198.1 8.3 ± 6.1 9.1 ± 6.5 16.6 ± 11.6 11.3 ± 3.5 10.1 ± 10.9 13.1 ± 6.0 20.8 ± 4.6 9.3 ± 4.1 −2.8 ± 7.3 −0.7 ± 13.6 −7.7 ± 17.4 30.3 ± 13.2 −14.0 ± 11.9 −4.2 ± 12.6 −4.4 ± 8.0 −12.5 ± 12.5 −20.8 ± 12.7 6.2 ± 8.9 −9.0 ± 10.2 4.8 ± 8.0 −3.2 ± 17.5 −13.9 ± 7.6 −4.5 ± 9.4 16.3 ± 5.6 19.2 ± 5.9 2.2 ± 10.7 5.7 ± 3.2 −3.5 ± 9.4 4.8 ± 5.4 9.9 ± 4.4 10.8 ± 4.0 12.3 ± 6.9 −4.8 ± 10.5 1.6 ± 14.7 −4.2 ± 11.6 11.9 ± 11.4 −2.2 ± 11.1 7.2 ± 7.3 −6.0 ± 11.5 −1.1 ± 11.6 8.9 ± 8.1 1.7 ± 9.3 3.5 ± 7.4 −1.1 ± 15.8 1.0 ± 7.0 6.6 ± 8.1 Y/Y Y/Y Y/N Y/Y N/N Y/N Y/Y Y/Y N/Y N/N N/N Y/N Y/Y N/N Y/N N/N Y/N N/Y N/N N/N N/N Y/N N/N 80.0 69.2 74.2 216.1 203.6 204.9 5.4 6.6 5.0 74.3 77.2 75.9 198.1 193.9 196.0 −7.1 ± 8.8 8.4 ± 7.5 1.4 ± 6.1 2.2 ± 8.1 3.8 ± 6.9 2.6 ± 5.6 N/N Y/N N/N Note: Sign = Significance (Y: Yes, N: No), Ref = Reference, K1 = Early Cretaceous, K2 = Late Cretaceous, K = Cretaceous, J3–K = Late Jurassic–Cretaceous, K2–E = Late Cretaceous–Eocene, E = Eocene Rotation and latitudinal translation were calculated at each study locality following Butler (1992); negative (positive) sign indicates CCW (CW) rotation and southward (northward) translation, respectively Expected VGPs are calculated from Eurasian poles (Table 1) derived by Besse and Courtillot (1991) (1) = Chan (1991), (2) = Gilder et al (1993), (3) = Funahara et al (1992), (4) = Hu et al (1990), (5) = Zhai et al (1992), (6) = Huang and Opdyke (1992a), (7) = Zhu et al (1988), (8) = Lin (1984), (9) = Enkin et al (1991a), (10) = Enkin et al (1991b), (11) = Otofuji et al (1990), (12) = Kent et al (1986), (13) = Yoshioka et al (2003), (14) = Otofuji et al (1998), (15) = Hsu (1987), (16) = Gilder et al (1999), (17) = Li et al (1995) 120 110 100 90 80 70 60 50 40 30 20 10 -10 -20 -30 -40 Jinggu (K1) (clockwise) Ten sites with 76 oriented core samples were collected from Late Jurassic and Cretaceous extrusive, intrusive, and red bed rocks from the Tu Le Depression and Song Da Terrane, situated just to the south of the Red River fault (Figure of Chi et al., 2000) The analysis of the rock magnetic properties and the response to progressive AF and thermal demagnetization of rock samples reveals that the principal remanence carrier in the extrusive and intrusive rocks sampled is nearly pure to low Ti magnetite and that of red beds sampled is hematite (Chi et al., 2000) The paleomagnetic results (Table 3) are interpreted to suggest that the area studied in northwest Vietnam has not been significantly rotated nor translated in a latitudinal sense relative to the South China Block or the Eurasia continent since the Cretaceous (Table 5, Figs and 6) The results are consistent with those reported by Huang and Opdyke (1993), from Upper Cretaceous red bed strata near Xiaguan, in southwestern Yunnan, China, situated adjacent to the Red River fault Chi et al (2000) determined a Late Jurassic–Cretaceous paleomagnetic pole for the northwest region of Vietnam, which is located at 83.9◦ N, 233.1◦ E (A95 = 11.9◦ ) This pole is statistically indistinguishable from the Rotation Magnitude, in degrees 3.1 Northwestern Vietnam Late Cretaceous paleomagnetic pole for the Xiaguan area (83.6◦ N, 152.7◦ E, A95 = 10◦ ) reported by Huang and Opdyke (1993), but both of these results are associated with relatively high dispersion The two reported poles are also indistinguishable from Cretaceous paleomagnetic poles for the South China block and Eurasia continent at 95% confidence level, which further corroborates Huang and Opdyke’s (1993) conclusion that the Red River fault does not demarcate unrotated and significantly rotated regions (Huang and Opdyke, 1993) More recently, Takemoto et al (2005) reported data from the Yen Chau Formation, consisting of mid-Cretaceous red bed that are part of the Song Da Terrane in northwest Vietnam Fifteen sites, with six to ten hand samples at each site, were collected at Yen Chau and Lai Chau localities along the road No leading from (counterclockwise) rock units of Cretaceous age in Vietnam The results of these studies have been published in Vietnamese and international journals (Chi, 1996, 2001; Chi et al., 1998, 1999, 2000; Chi and Dorobek, 2004) The second author is in the processes of preparing a contribution on a collection of Cretaceous red beds obtained in 2009 and some preliminary results are presented here The results of all of these studies are summarized below; information on individual site data and characteristics of the paleomagnetism of each rock unit is in the original papers Lanping Mengla (Eocene) (Eocene) Jinggu (K2) Simao T errane Mengla (K2) Y ongping (K1) Shan P lateau (J3-K) Southern Vietnam (K) Plateau (J3-K1) 11 12 13 14 Yunlong (K2) Khorat 15 16 Lanping 21 20 19 18 17 Northern V ietnam (J3-K) o 22 23 24 25 (K2) 26 27 Xiaguan (K2) Locality Latitude, N Fig Relative rotation of elements of the Indochina-Shan Thai terranes, as a function of the latitude of the sampling area, with respect to Eurasia Vertical bars represent the uncertainty of each result, as represented by ˛95 values Please cite this article in press as: Cung, T.C., Geissman, J.W., A review of the paleomagnetic data from Cretaceous to lower Tertiary rocks from Vietnam, Indochina and South China, and their implications for Cenozoic tectonism in Vietnam and adjacent areas J Geodyn (2013), doi:10.1016/j.jog.2011.11.008 ARTICLE IN PRESS G Model GEOD-1103; No of Pages 11 T.C Cung, J.W Geissman / Journal of Geodynamics xxx (2013) xxx–xxx Table Paleomagnetic results of Late Jurassic–Cretaceous rocks from northwestern Vietnam Site Location Rock type Age Lat (◦ N) GP BH1 BH2 TL PT NTH SR 21.15 21.47 21.47 21.69 22.53 21.48 21.28 104.65 104.38 104.38 104.45 103.28 104.42 104.70 Volcanic tuff Rhyolitic tuff Rhyolitic porphyry Volcanic ash Sandstone Rhyolite Redbed siltstone J3–K J3–K J3–K J3–K K K K YC 21.05 104.27 Redbed siltstone QH OQ 22.36 22.37 103.78 103.73 Granite Granite n/N Long (◦ E) ChRM direction VGP Dg (◦ ) Ig (◦ ) Ds (◦ ) Is (◦ ) ˛95 k Lat (◦ N) Long (◦ E) 5/5 6/6 7/7 8/8 6/7 6/6 9/9 37.2 357.8 353.8 5.6 338.6 358.5 21.1 56.1 34.7 26.9 49.5 48.8 23.4 −30.6 K2 12/12 188.0 −36.5 K2–Pg K2–Pg 8/8 7/8 347.7 18.9 18.3 21.9 – – – – – – – 22.3 – 192.6 – – – – – – – – – 8.4 – −15.6 – – 9.6 2.6 6.2 7.9 12.7 5.1 7.8 7.2 14.9 14.7 9.2 4.6 34.0 669.5 94.5 24.1 14.2 170.3 44.9 52.6 9.4 9.7 37.5 88.9 54.3 86.6 80.4 80.4 69.7 80.3 46.8 62.3 82.5 72.1 72.3 68.7 161.3 321.8 323.8 135.1 37.7 293.4 254.9 230.6 199.1 239.8 328.0 223.0 10 – – 4.9 31.2 13.1 14.5 83.9 233.1 Mean: Note: N = total number of samples; n = number of samples used in calculation of mean directions; ChRM = characteristic remanent magnetization; Dg , Ig = geographic (in situ) declination and inclination; Ds , Is = stratigraphic (tilt corrected) declination and inclination; ˛95 = radius of 95% confidence circle; k = precision parameter; VGP = Virtual Geomagnetic Pole; J3–K = Late Jurassic-Cretaceous; K2–Pg = Late Cretaceous–Paleogene; K2 = Late Cretaceous Hoa Binh to Son La and Lai Chau Thirteen sites yield a positive fold test and give a grand mean mid-Cretaceous paleomagnetic direction (D = 6.4◦ , I = 32.0◦ , ˛95 = 8.5◦ ) that corresponds to a paleomagnetic pole located at 82.9◦ N, 220.7◦ E (A95 = 6.9◦ ) Their results are consistent with results reported by Chi et al (2000), (Table 5, Figs and 5) On the basis of a paleomagnetic collection involving ten separate localities, with 6–19 sites collected per locality and seven to 15 samples collected from each site, Geissman (unpublished data, 2011) concluded that, overall, the paleomagnetic data from this area are consistent with those reported by Takemoto et al (2005), and that, depending on the locality investigated, the remanence in these mid-Cretaceous strata is heavily contaminated by a relatively recent, post-folding magnetization (Fig 7) Overall, the paleomagnetic results from the three areas located along and immediately southwest of the Red River fault system in northern Vietnam suggest that the fault does not demarcate nonrotated and significantly rotated crust If elements of the Indochina Block had been extruded by a significant amount, in a southeast directed fashion, as suggested by proponents of the extrusion tectonics, it must have taken place on some other faults located farther to the southwest of the Red River fault Cretaceous paleomagnetic results from the Indochina–Shan Thai Block 3.2 Southern Vietnam (northward) 25 20 15 -5 Mengla Lanping (Eocene) (Eocene) Shan P lateau Northern Mengla (K2) (southward) Latitudinal Translation, in degrees Twenty four sites with a total of 163 core samples were collected from Cretaceous volcanic, intrusive and sedimentary rocks in southern Vietnam (Chi and Dorobek, 2004) The distribution of VGPs from the accepted sites (Table 4), when compared with 10 96 97 98 99 Lanping (K2) 100 Vietnam Jinggu (K1) 104 101 102 Jinggu (K2) -10 -15 -20 Khorat P lateau 105 106 107 108 Southern Vietnam Simao Terrane -25 Yongping (K1) -30 -35 the Eurasia mean Cretaceous paleopole, may indicate a very slight southward displacement of southern Vietnam (6.5 ± 5.1◦ ), yet no appreciable rotation since the Cretaceous (Table 5, Figs and 5) Given that this is the only set of paleomagnetic results from southern Vietnam and that the data are from a wide range of rock types, this result, although it represents the only data available from southern Vietnam, should be considered of limited importance The available paleomagnetic data from Cretaceous rocks in northwest and southern Vietnam may support some degree of internal deformation of this region in response to the India–Eurasia collision, but the distribution of the data remains far too sparse to provide firm conclusions The possible southward displacement, yet insignificant rotation of southern Vietnam, may reflect north–south oriented spreading in the northern part of South China Sea with the development of a major right-lateral transform fault system that extended just off the eastern continental margin of Vietnam (Taylor and Hayes, 1980, 1983) High quality paleomagnetic data are sorely needed from Cretaceous rocks from the far northeast part of Vietnam, east of the Red River fault system Locality Longitude, o E Fig Relative translation of the Indochina-Shan Thai terranes, as a function of the longitude of the sampling area, with respect to Eurasia Vertical bars represent the uncertainty of each determination, as represented by the ˛95 values A term that has often been used in reference to tectonic models of Cenozoic deformation in the Southeast Asia region, and referred to in the introduction, is the ‘Sundaland’ plate The Sundaland plate is defined to the northeast by the Red River fault, to the west by the Sagaing fault in Myanmar, to the east by the Philippine subduction zone, and to the south by the Indonesia subduction zone (Fig 1) This plate includes the Shan-Thai and Indochina blocks, southwest East Vietnam Sea, Borneo and Malaya-Indonesia islands Paleomagnetic data from farther south in the Sundaland plate (Fuller et al., 1991; Richter and Fuller, 1996) were used to evaluate the Cenozoic tectonic evolution of this region and reflect the tectonic complexity of the Southeast Asian region Opposite sense rotations with different magnitudes of rotation have been observed from the same terrane or from different terranes Data from the interior part of Sundaland are supportive of some magnitude of clockwise rotation, although counterclockwise rotations appear to characterize the Indonesian peninsula and islands located in the southeastern part of the region The Cretaceous paleomagnetic data of the Shan-Thai and Indochina blocks obtained over the past two decades or so highlight the nature and potential complexities of intraplate deformation due to the impact of India–Eurasia collision According to Please cite this article in press as: Cung, T.C., Geissman, J.W., A review of the paleomagnetic data from Cretaceous to lower Tertiary rocks from Vietnam, Indochina and South China, and their implications for Cenozoic tectonism in Vietnam and adjacent areas J Geodyn (2013), doi:10.1016/j.jog.2011.11.008 G Model GEOD-1103; No of Pages 11 ARTICLE IN PRESS T.C Cung, J.W Geissman / Journal of Geodynamics xxx (2013) xxx–xxx Fig Some preliminary paleomagnetic results from Cretaceous redbeds in northwest Vietnam (a, b) Relatively recent road construction activities have resulted in abundant road exposures of relatively fresh bedrock in this area (c–i) Examples of response to progressive demagnetization by Cretaceous redbeds Orthogonal demagnetization diagrams showing the endpoint of the magnetization vector plotted onto the horizontal (filled symbols) and vertical (open symbols) planes (Zijderveld, 1967) Selected demagnetization steps are show adjacent to vertical projections All diagrams in geographic coordinates (c–e) Demagnetization results showing the removal of a northdirected and steep positive inclination (in geographic coordinates) magnetization followed, at high laboratory unblocking temperatures, a magnetization that is northwestdirected and shallow inclination that, in stratigraphic coordinates is north–northeast directed and moderate positive in inclination and is interpreted as a primary remanence (f and g) Demagnetization results showing the first-removal of a north-directed and moderate positive inclination magnetization, followed by an east-directed and shallow magnetization Results from this locality are interpreted to suggest a considerable magnitude clockwise rotation, that is inconsistent with other data from northwest Vietnam and likely reflective of a local structural feature (h and i) Examples of results where a moderate negative inclination magnetization predominates; after structural correction this magnetization is south-directed and of relatively shallow inclination, and thus interpreted as a reverse polarity primary magnetization Please cite this article in press as: Cung, T.C., Geissman, J.W., A review of the paleomagnetic data from Cretaceous to lower Tertiary rocks from Vietnam, Indochina and South China, and their implications for Cenozoic tectonism in Vietnam and adjacent areas J Geodyn (2013), doi:10.1016/j.jog.2011.11.008 ARTICLE IN PRESS G Model GEOD-1103; No of Pages 11 T.C Cung, J.W Geissman / Journal of Geodynamics xxx (2013) xxx–xxx Table Paleomagnetic results of Cretaceous rock formations from southern Vietnam Site Location Rock type Lat (◦ N) 8703 8705 8706 8707a 8708 8709 8710 8711 8713 PH NH BD2a BD1 DL BN RR TR NT VT DC CN NS CT THIa 12.47 12.29 12.20 12.06 11.85 11.76 11.88 11.78 11.69 11.62 12.47 11.39 11.39 11.90 11.80 12.33 12.31 11.27 10.35 12.88 11.36 10.68 10.37 10.56 109.13 109.21 109.21 108.53 108.58 108.51 108.47 108.42 108.38 108.20 109.13 106.19 106.15 108.45 109.11 109.20 109.19 108.73 107.07 109.38 108.87 105.08 105.02 107.08 St/Dp n/N ChRM direction Long (◦ E) Dg (◦ ) Ig (◦ ) VGP Ds (◦ ) Is (◦ ) ˛95 k s (◦ N) 18/24 – 34/18 – 265/04 254/06 295/15 07/23 281/06 266/18 18/24 – – – – – – – – – – – – – 7/7 6/6 5/5 4/5 4/6 6/10 6/6 6/7 7/9 7/7 8/8 8/8 6/6 5/7 7/7 8/8 8/8 6/6 3/3 6/6 6/6 7/8 8/8 4/6 18.1 354.7 2.5 65.7 28.0 24.5 12.7 349.1 21.3 13.1 5.6 70.7 26.4 15.9 27.8 6.3 4.5 13.0 354.5 13.6 34.5 155.7 23.3 315.9 36.9 34.6 37.3 34.0 44.4 40.6 36.8 40.1 41.9 51.3 39.5 26.4 22.5 33.9 34.4 54.3 23.6 37.7 15.6 26.3 30.9 –15.6 23.4 6.8 35.1 – 16.9 – 26.1 21.2 14.5 9.8 20.4 8.8 26.1 – – – – – – – – – – – – – 33.2 – 44.8 – 41.0 35.0 22.0 43.2 35.7 33.9 40.4 – – – – – – – – – – – – – 7.4 2.8 3.0 16.7 5.7 13.2 11.5 1.8 7.9 4.2 1.9 12.1 7.2 10.9 3.2 4.0 4.0 6.0 17.6 5.4 7.1 4.0 6.3 7.9 67.7 561.5 661.1 31.3 261.8 26.8 34.6 999.9 58.9 207.8 876.3 22.0 99.8 49.9 359.7 193.4 191.6 123.9 50.0 96.8 59.5 258.9 77.6 136.7 185.1 72.8 155.0 183.6 169.9 175.6 198.8 141.8 173.5 157.8 172.4 185.5 192.8 173.0 180.8 122.4 198.8 158.8 353.7 193.5 185.8 10.7 188.2 11.1 21/24 Mean of 21 sites: Rhyolitic tuff Rhyolite Trachyriolite Dacite Shalestone Andesitic tuff Red Siltstone Dacite Red Siltstone Red Siltstone Rhyolitic tuff Granodiorite Andesite Felsite Dacite Andesite Andesite Rhyolite Rhyolite Granite Granite Granite Granodiorite Granite 11.5 35.3 14.5 33.3 6.3 26.7 171.1 74.2 s (◦ E) 55.8 81.5 68.7 26.6 62.6 68.3 75.8 73.7 68.8 79.0 63.0 21.2 64.1 73.3 62.3 66.8 85.6 74.1 84.1 76.7 56.2 65.9 67.1 45.7 A95 6.8 2.4 3.0 14.4 5.4 11.5 8.8 1.8 7.0 3.6 1.8 9.7 5.6 9.4 2.8 4.7 3.1 5.4 13.0 4.3 5.9 2.9 4.9 5.6 5.9 Note: St = bedding strike, Dp = bedding dip, n = number of samples (sites) used in calculation of mean directions, N = total number of samples (sites), Dg (Ig ) = geographic declination (inclination), Ds (Is ) = stratigraphic declination (inclination), ˛95 (A95 ) = circle of 95% confidence, k = precision parameter, s ( s ) = stratigraphic latitude (longitude) a Indicates the sites which were not included in the mean calculation models proposed for the quasi-rigid extrusion of tectonic elements of Southeast Asia, the Indochina Block has experienced a net clockwise rotation of about 40◦ , and has been displaced southward some 800–1000 km, which under favorable circumstances is resolvable with paleomagnetic data, along the sinistral Red River and Me Kong River fault systems to accommodate deformation related to the convergence of the India–Eurasia collision The paleomagnetic data from Upper Jurassic to Lower Cretaceous sedimentary rocks from the Khorat Plateau (16.5◦ N, 103.0◦ E), Thailand (Yang and Besse, 1993) are cited as early acquired evidence in support of this model Based on a comparison with five selected Late Jurassic–Early Cretaceous paleopoles from the South China Block, Yang and Besse (1993) determined that the Indochina Block has rotated about 14◦ (14.2 ± 7.1◦ ) clockwise and was displaced some 11◦ southward (11.5 ± 6.7◦ ) relative to the South China Block since the Cretaceous If Late Jurassic to Early Cretaceous reference poles for the Eurasian continent are used as a reference, however, the estimated magnitude of Khorat Plateau clockwise rotation is less (10.2 ± 7.3◦ ) and the estimated magnitude of southward displacement is insignificant (3.4 ± 6.9◦ ) (Table 5, Figs and 5) As noted above, the selection of accurate reference paleomagnetic poles is critical for reliable tectonic interpretation Table Cretaceous–Eocene paleomagnetic results of the Indochina Block Locality Lat (◦ N) Long (◦ E) Age Observed VGP ◦ ◦ Expected VGP 21.7 21.7 11.7 16.5 103.9 104.2 108.2 103.0 K2 J3–K K J3–K1 26.5 23.5 25.8 25.6 23.4 21.6 25.8 25.5 23.5 20.4 99.3 100.7 99.4 100.2 100.9 100.4 99.4 99.5 100.7 96.3 E E K2 K2 K2 K2 K2 K1 K1 J3–K ( N) ◦ ( E) Rotation R± Translation Significance Ref ± ( N) Indochina Block: Song Da Terrane Tu Le Depression South Vietnam Khorat Plateau Shan-Thai Block: Simao Terrane: Lanping Mengla Yunlong Xiaguan Jinggu Mengla Lanping Yongping Jinggu Shan Plateau A95 ◦ ( E) R 82.9 83.9 74.2 63.8 220.7 233.1 171.1 175.6 6.9 11.9 5.9 1.7 77.2 75.4 75.9 73.7 193.9 186.6 196.0 181.8 −7.0 −10.7 0.4 10.2 ± ± ± ± 7.6 13.1 5.4 7.3 2.7 5.1 −6.5 −3.4 ± ± ± ± 7.1 12.4 5.1 6.9 N/N N/N N/Y Y/N (1) (2) (3) (4) 14.5 13.2 54.6 83.6 18.9 33.7 69.7 50.9 −13.9 46.4 169.7 172.2 171.3 152.7 170.0 179.3 167.6 167.3 161.3 190.6 10.9 5.4 4.4 10.0 8.9 8.2 6.9 20.6 4.3 3.5 79.8 79.8 77.2 77.2 77.2 77.2 77.2 74.3 74.3 75.4 143.1 143.1 193.9 193.9 193.9 193.9 193.9 198.1 198.1 186.6 76.5 76.7 26.0 −8.2 65.7 47.2 8.2 27.5 99.2 29.1 ± ± ± ± ± ± ± ± ± ± 12.6 6.9 5.6 11.7 10.1 9.0 8.4 25.7 7.9 5.2 9.9 8.8 −7.0 −5.3 −3.9 −0.4 −7.5 −11.1 0.6 7.8 ± ± ± ± ± ± ± ± ± ± 11.4 6.4 4.9 10.2 9.1 8.5 7.1 21.5 7.4 4.0 Y/N Y/Y Y/Y N/N Y/N Y/N N/Y Y/N Y/N Y/Y (5) (10) (6) (7) (7) (7) (9) (8) (10) (11) Note: Ref = reference, significance (Y = Yes, N = No) K1 = Early Cretaceous, K2 = Late Cretaceous, K = Cretaceous, J3–K = Late Jurassic–Cretaceous, J3–K1 = Late Jurassic–Early Cretaceous, E = Eocene Rotation and latitudinal translation were calculated at each study locality following Butler (1992); negative (positive) sign indicates CCW (CW) rotation and southward (northward) translation, respectively Expected poles are calculated (Table 1) from Eurasian poles derived by Besse and Courtillot (1991) (1) = Takemoto et al (2005), (2) = Chi et al (2000), (3) = Chi and Dorobek (2004), (4) = Yang and Besse (1993), (5) = Sato et al (2001), (6) = Sato et al (1999), (7) = Huang and Opdyke (1993), (8) = Funahara et al (1993), (9) = Yang et al (2001), (10) = Chen et al (1995), (11) = Richter and Fuller (1996) Please cite this article in press as: Cung, T.C., Geissman, J.W., A review of the paleomagnetic data from Cretaceous to lower Tertiary rocks from Vietnam, Indochina and South China, and their implications for Cenozoic tectonism in Vietnam and adjacent areas J Geodyn (2013), doi:10.1016/j.jog.2011.11.008 G Model GEOD-1103; No of Pages 11 ARTICLE IN PRESS T.C Cung, J.W Geissman / Journal of Geodynamics xxx (2013) xxx–xxx of paleomagnetic results from a particular area, in particular when magnitudes of rotation and latitudinal translation may be relatively small Many paleomagnetic studies have been carried out on Cretaceous to Eocene red bed formations from the Lanping-Simao Terrane in western Yunnan, China (Huang and Opdyke, 1993; Chen et al., 1995; Sato et al., 1999, 2001; Yang et al., 2001; Burchfiel et al., 2007; Geissman et al., 2011, in preparation) In terms of geographic location, this area is part of western Yunnan Province, China, yet in a tectonic context, the area is within the Shan Thai Block near the eastern syntaxis of the India–Eurasia collision belt (Fig 1); where locally intense internal deformation, involving folding and faulting of thick upper Paleozoic through lower Tertiary strata occurred in response to the India–Eurasia collision and displacement of components of southeast Asia (Wang and Burchfiel, 1997) A range of paleomagnetic results have been obtained from Cretaceous to Eocene red bed strata from different localities in this broad region, reflecting a heterogeneous deformation field Inferred clockwise rotations of local regions within the Lanping Simao belt are as large as 100◦ , and estimates of southward latitudinal displacement relative to both the Eurasia and the South China reference frames range from insignificant to, more typically, about 10◦ and no greater than 12◦ (Table 5, Figs and 6) The areas that are interpreted to have experienced large magnitudes of rotation likely reflect local deformation of upper-crustal elements during differential crustal shortening (MacDonald, 1980; Burchfiel et al., 2007) In some areas of the belt, such as near Lanping and Mengla, somewhat larger magnitudes of clockwise rotation are suggested by data from Eocene red beds, although lesser clockwise rotations have been estimated based on data from underlying Upper Cretaceous red beds (Fig 5) Similar, seemingly conflicting results have been obtained for inferred latitudinal displacements, with younger, overlying redbeds yielding larger values than older rocks (Fig 6) It is possible that these data sets may imply the complexity of local tectonic displacements Alternative interpretations involve the overall reliability of the age interpretation of the rocks and, more importantly, the age of their characteristic magnetization It is often difficult to determine a sufficiently accurate age of thick sequences of medium to coarse grained continental red beds because fossils are uncommon Age assignments for red bed sequences are often based on stratigraphic correlations, and, together with inaccuracies in interpreting the ages of magnetizations characteristic of the rocks, these can result in inaccurate tectonic interpretations of paleomagnetic data, leading to unreasonable conclusions, especially in strongly deformed rocks, like parts of Southeast Asia Paleomagnetic data from Upper Jurassic to Cretaceous continental red beds, exposed near the western margin of the Shan Thai Block near the Sagaing right-lateral strike-slip fault (Fig 1), show that the study area was rotated in a clockwise sense by nearly 30◦ (29.1 ± 5.2◦ ) and may have been translated northward by about 8◦ (7.8 ± 4.0◦ ) (Richter and Fuller, 1996) (Table 3, Figs and 5) A component of the inferred deformation of this area is likely a consequence of dextral displacement along the more than 1000 km long Sagaing fault system, that formed and during the India–Eurasia collision process and remains very active (Vigny et al., 2003; Tsutsumi and Sato, 2009) Under those circumstances where there is ample evidence of sufficient averaging of the geomagnetic field and that data can be accurately referenced to the paleohorizontal, paleomagnetic data can provide a powerful means of quantifying important components of the deformation matrix, specifically vertical axis rotation and latitudinal components of displacement Paleomagnetic data based on studies that have concentrated or targeted sampling in tectonically active areas must be interpreted with caution, as they represent the cumulative sum of all components of deformation experienced by the rocks studied and thus may not be an accurate representation of the phase of deformation of interest (e.g., over a specific time interval) Rarely is it the case that a single set of observations from a relatively restricted locality an accurate reflection of the coherent motion of the entire lithospheric block Caution should be taken in the interpretation of paleomagnetically defined rotations and/or translations of specific areas, in particular in the context of the motion of features that encompass a considerably larger area than that examined in the paleomagnetic study Conclusions In the context of the history of late Mesozoic to present deformation of Vietnam and immediately adjacent areas, overall, the paleomagnetic data from Cretaceous and Paleogene sedimentary rocks from the South China Block and Indochina regions can be interpreted to indicate that the South China Block has been relatively stable with respect to the Eurasian continent at least since the Cretaceous Components of vertical axis rotation and latitudinal translation, dominantly in a south-directed sense, have contributed to the deformation of crustal to lithosphere scale elements of Southeast Asia We suspect that results from some localities reflect more localized deformation of elements confined to the upper crust, rather than involving an entire lithosphere section The India–Eurasia collision strongly deformed the Indochina–Shan Thai Block, in particular in the areas near the collision belt During the Cenozoic, Indochina and parts of Sundaland experienced complex internal deformation and clearly did not behave as a coherent block, as suggested by extrusion models The Red River fault system, which is juxtaposed on or adjacent to the long-lived left lateral Ailao Shan shear zone, may not entirely demarcate the South China Block and the Indochina Block Some of the available paleomagnetic data are interpreted to suggest that at least some terranes located southwest of the fault system have not been significantly rotated nor translated southward relative to the South China block since the Cretaceous However, the preponderance of paleomagnetic results from much of the Lanping Simao belt in western Yunnan Province, China, in consistent with a modest amount of southward displacement, and variable clockwise rotation, with the observed range in rotation magnitudes possibly reflecting more localized deformation unrelated to that affecting the remainder of the lithosphere in this region A mobile, more lithosphere scale boundary between the South China and Indochina blocks in the extrusion model is possibly located, at the latitude of northwest Vietnam, southwest of the Red River fault Although the data upon which this is based are very sparse, the inferred very modest southward displacement of the southern part of Vietnam may be consistent with the extrusion model, however, no clockwise rotation has been observed from this area Modest magnitude counterclockwise rotations appear to characterize the Borneo and Malaya peninsula areas, located farther to the south (Fuller et al., 1991), indicating that the complex tectonic evolution of the Southeast Asian region cannot be completely explained by any single, simple tectonic model Acknowledgements The research has been supported by a grant for the basic research project (No 105.03.05.09) from National Foundation for Science and Technology Development (Nafosted) of Vietnam to Cung Thuong Chi In addition, Geissman acknowledges support from National Science Foundation awards EAR9706300 and EAR0537604 Mr Scott Muggleton assisted Geissman with field sampling in northern Vietnam; and the collaboration with Dr N.V Pho over this time period is greatly appreciated We wish to thank Dr Mike Fuller for helpful comments on the manuscript Please cite this article in press as: Cung, T.C., Geissman, J.W., A review of the paleomagnetic data from Cretaceous to lower Tertiary rocks from Vietnam, Indochina and South China, and their implications for Cenozoic tectonism in Vietnam and adjacent areas J Geodyn (2013), doi:10.1016/j.jog.2011.11.008 G Model GEOD-1103; No of Pages 11 10 ARTICLE IN PRESS T.C Cung, J.W Geissman / Journal of Geodynamics xxx (2013) xxx–xxx References Besse, J., Courtillot, V., 1991 Revised and synthetic apparent polar wander paths of the African, Eurasian, North America and Indian Plates, and true polar wander since 200 Ma Journal of Geophysical Research B96, 4029–4050 Besse, J., Courtillot, V., 2002 Apparent and true polar wander and the geometry of the geomagnetic field over the last 200 Myr – art no 2300 Journal of Geophysical Research-Solid Earth 107 (B11), 2300 Bilardello, D., Kodama, K.P., 2009 Measuring remanence anisotropy of hematite in red beds: anisotropy of high field isothermal remanence magnetization (hf-AIR) Geophysical Journal International 178, 1260–1273 Bilardello, D., Kodama, K.P., 2010 Rock magnetic evidence for inclination shallowing in the early Carboniferous Deer Lake Group red beds of western Newfoundland Geophysical Journal International 181, 275–289 Burchfiel, B.C., Studnicki-Gizbert, C., Geissman, J.W., Wang, E., Lianzhong, C., 2007 How much strain can continental crust accommodate without developing obvious, through-going faults? In: Whence the Mountains? Inquiries into the Evolution of Orogenic Systems: A Volume in Honor of Raymond A Price Geological Society of America Special Paper 433 Geological Society of America, Boulder, pp 51–62 Butler, R., 1992 Paleomagnetism Blackwell Scientific Publications, Boston, USA Chan, L.S., 1991 Paleomagnetism of late Mesozoic granitic intrusions in Hong Kong: implications for Upper Cretaceous reference pole of South China Journal of Geophysical Research 96B, 327–335 Chen, H., Dobson, J., Heller, F., Hao, J., 1995 Paleomagnetic evidence for clockwise rotation of the Simao region since the Cretaceous: a consequence of India–Asia collision Earth and Planetary Science Letters 134, 203–217 Chen, Y., Courtillot, V., Cogne, J.P., Besse, J., Yang, Z., Enkin, R.J., 1993 The configuration of Asia prior to the collision of India: Cretaceous paleomagnetic constraints Journal of Geophysical Research B98, 21927–21941 Chi, C.T., Dorobek, S.L., 2004 Cretaceous palaeomagnetism of Indochina and surrounding regions: Cenozoic tectonic implications In: Malpas, J., Fletcher, C.J.N., Ali, J.R., Aitchison, J.C (Eds.), Aspects of the Tectonic Evolution of China, vol 226 Geological Society, London, Special Publication Chi, C.T., 2001 Results of paleomagnetic study on Jurassic sandstone and siltstone of the Ha Coi formation and their tectonic implications Journal of Geology, Series B 17–18, 35–44 Chi, C.T., Yem, N.T., Cuong, N.Q., 2000 Paleomagnetic results of Late Jurassic–Cretaceous extrusive and intrusive rocks from northwestern region of Vietnam Journal of Geology, Series A 256 (1–2), 1–8 (in Vietnamese) Chi, C.T., Cuong, N.Q., Yem, N.T., 1999 Paleomagnetic results of Cretaceous rock formations from South-east Asia region and from South China block: their tectonic implications Journal of Geology, Series A 252 (5–6), 8–17 (in Vietnamese) Chi, C.T., Yem, N.T., Bao, N.X., 1998 Paleomagnetic study of Late Jurassic-Cretaceous extrusive and intrusive igneous rocks from South Vietnam: tectonic implications for the Cenozoic tectonic history of Indochina Block Journal of Geology, Series A 249 (11–12), 1–8 (in Vietnamese) Chi, C.T., 1996 Paleomagnetism of Mesozoic and Cenozoic rocks from Vietnam: implications for the Tertiary tectonic history of Indochina and a test of the extrusion model PhD Thesis Texas A&M University, College Station, Texas Dewey, J.F., Cande, S., Pitman III, W.C., 1989 Tectonic evolution of the India/Eurasia collision zone Eclogae Geologicae Helvetiae 82, 717–734 Donohoo-Hurley, L.L., 2011 Magnetic records from uppermost Triassic to earliest Jurassic Red Beds, Utah and Arizona, and from mid-Pleistocene lake beds, New Mexico Earth and Planetary Sciences Albuquerque, University of New Mexico PhD, p 149 Donohoo-Hurley, L.L., Geissman, J.W., Wawrzyniec, T.F., Roy, M., Inclination bias of the uppermost Triassic to lowermost Jurassic Moenave Formation, Utah and Arizona: how can time-equivalent data from the American Southwest be reconciled with those from eastern North America? in preparation England, P.C., Houseman, G.A., 1989 Extension during continental convergence, with application to the Tibetan Plateau Journal of Geophysical Research 94B, 17561–17579 England, P.C., Molnar, P., 1990 Right lateral shear and rotation as the explanation for strike-slip faulting in eastern Tibet Nature 344, 140–142 Enkin, R.J., Chen, Y., Courtillot, V., Besse, J., Xing, I., Zhang, Z., Zhuang, Z., Zhang, J., 1991a A Cretaceous pole from South China and the Mesozoic hairpin turn of the Eurasian apparent polar wander path Journal of Geophysical Research 96B, 4007–4027 Enkin, R.J., Courtillot, V., Xing, I., Zhang, Z., Zhuang, Z., 1991b The stationary Cretaceous paleomagnetic pole of Sichuan (South China Block) Tectonics 10, 547–559 Enkin, R.J., Yang, Z., Chen, Y., Courtillot, V., 1992 Paleomagnetic constraints on the geodynamic history of the major blocks of China from the Permian to the present Journal of Geophysical Research B97, 13953–13989 Fuller, M., Haston, R., Lin, J., Richter, B., Schmidtke, E., Almasco, J., 1991 Tertiary paleomagnetism of regions around the South China Sea Journal of Southeast Asian Earth Sciences 6, 161–184 Funahara, S., Nishiwaki, N., Miki, M., Murata, F., Otofuji, Y-I., Wang, Y.Z., 1992 Paleomagnetic study of Cretaceous rocks from the Yangtze block, central Yunnan, China: implications for the India–Asia collision Earth and Planetary Science Letters 113, 77–91 Funahara, S., Nishiwaki, N., Miki, M., Murat, F., Otofuji, Y-I., Wang, Y.Z., 1993 Clockwise rotation of the Red River fault inferred from paleomagnetic study of Cretaceous rocks in the Shan-Thai-Malay block of western Yunnan, China Earth and Planetary Science Letters 117, 29–42 Gilder, S., Coe, R., Wu, H., Kuang, G., Zhao, X., Wu, Q., Tang, X., 1993 Cretaceous and Tertiary paleomagnetic results from southeast-China and their tectonic implications Earth and Planetary Science Letters 117, 637–652 Gilder, S.A., Gill, J., Coe, R.S., Zhao, X., Liu, Z., Wang, G., Yuan, K., Liu, W., Kuang, G., Wu, H., 1996 Isotopic and paleomagnetic constraints on the Mesozoic tectonic evolution of South China Journal of Geophysical Research 101 (B7), 16137–16154 Gilder, S.A., LeLoup, P.H., Courtillot, V., Chen, Y., Coe, R., Zhao, X.X., Xiao, W.J., Halim, N., Cogne, J.P., Zhu, R., 1999 Tectonic evolution of the Tancheng-Lujiang (TanLu) Fault via Middle Triassic to Early Cenozoic paleomagnetic data Journal of Geophysical Research 104 (15), 365–375 Gillett, S.L., Geissman, J.W., 1993 Regional late Paleozoic remagnetization of shallow-water carbonate rocks in the Great Basin: the usefulness of micro-fold tests from late compaction fabrics In: Applications of Paleomagnetism to Sedimentary Geology SEPM (Society for Sedimentary Geology), pp 129–147 Hankard, F., Cogne, J.-P., Kravchinsky, V., 2005 A new Late Cretaceous paleomagnetic pole for the west of Amuria block (Khurmen Uul, Mongolia) Earth and Planetary Science Letters 236, 359–373 Hu, L., Li, P., Ma, X., 1990 A magnetostratigraphic study of Cretaceous redbeds from Shanghan, western Fujian, China (in Chinese) Geology of Fujian 1, 33–42 Huang, K., Opdyke, N.D., 1992a Paleomagnetism of Cretaceous to lower Tertiary rocks from southwestern Sichuan: a revisit Earth and Planetary Science Letters 112, 29–40 Huang, K., Opdyke, N.D., 1993 Paleomagnetic results from Cretaceous and Jurassic rocks of south and southwest Yunnan: evidence for large clockwise rotation in the Indochina and Shan-Thai-Malay terranes Earth and Planetary Science Letters 117, 507–524 Hsu, V., 1987 Paleomagnetic results from one of the red basins in South China EOS Trans AGU 68, 295 Hsu, K.J., Shuh, S., Li, J., Chen, H., Pen, H., Sengor, A.M.C., 1988 Mesozoic overthrust tectonics in south China Geology 16, 418–421 Jackson, J., Molnar, P., 1990 Active faulting and block rotation in the western Transverse Ranges, California Journal of Geophysical Research 95 (B13), 22073–22078 Kent, D.V., Xu, G., Huang, K., Zhang, W.Y., Opdyke, N.D., 1986 Paleomagnetism of Upper Cretaceous rocks from South China Earth and Planetary Science Letters 79, 179–184 Kent, D.V., Olsen, P.E., 2008 Early Jurassic magnetostratigraphy and paleolatitudes from the Hartford continental rift basin (eastern North America): testing for polarity bias and abrupt polar wander in association with the Central Atlantic magmatic province Journal of Geophysical Research 113, B06105, doi:06110.01029/02007JB005407 Leloup, P., Arnaud, N., Lacassin, R., Kienast, J., Harrison, T., Trong, T., Replumaz, A., Tapponnier, P., 2001 New constraints on the structure, thermochronology, and timing of the Ailao Shan-Red River shear zone, SE Asia Journal of Geophysical Research 106 (B4), 6683–6732 Li, Z., Metcalfe, I., Wang, X.F., 1995 Vertical-axis block rotation in southeast China: new paleomagnetic results from Hainan Island Geophysical Research Letters 22, 3071–3074 Lin, J., 1984 The apparent polar wander paths for the North and South China blocks PhD Thesis University of California, Santa Barbara Lowrie, W., Hirt, A., Kligfield, R., 1986 Effects of tectonic deformation on the remanent magnetization of rocks Tectonics 5, 713–722 MacDonald, W.D., 1980 Net tectonic rotation, apparent tectonic rotation, and the structural tilt correction in paleomagnetic studies Journal of Geophysical Research B85, 3659–3669 McCabe, C., Elmore, R.D., 1989 The occurrence and origin of late Paleozoic remagnetization in the sedimentary rocks of North America Review of Geophysics 27, 471–494 Minyuk, P.S., Stone, D.B., 2009 Paleomagnetic determination of paleolatitude and rotation of Bering Islands (Komandorsky Islands) Russia: comparison with rotations in the Aleutian Islands and Kamtchatka Stephan Mueller Special Publication Series 4, 329–348 Otofuji, Y-I., Inoue, Y., Funahara, S., Murata, F., Zheng, X., 1990 Paleomagnetic study of eastern Tibet – deformation of the Three Rivers region Geophysical Journal International 103, 85–94 Otofuji, Y-I., Liu, Y., Yokoyama, M., Tamai, M., Yin, J., 1998 Tectonic deformation of the southwestern part of the Yangtze craton inferred from paleomagnetism Earth and Planetary Science Letters 156, 47–60 Pares, J.M., Van der Pluijm, B.A., Dinares-Turell, J., 1999 Evolution of magnetic fabrics during incipient deformation of mudrocks (Pyrenees, northern Spain) Tectonophysics 307, 1–14 Peltzer, G., Tapponnier, P., 1988 Formation and evolution of strike-slip faults, rifts, and basins during the India–Asia collision: an experimental approach Journal of Geophysical Research 93B, 15085–15117 Pueyo, E.L., Pocovi, A., Millan, H., Sussman, A.J., 2004 Map-view models for correcting and and calculating shortening estimates in rotated thrust faults using paleomagnetic data Boulder, Geological Society of America Special Paper 383, 57–71 Replumaz, A., Tapponnier, P., 2003 Reconstruction of the deformed collision zone between India and Asia by backward motion of lithosphere blocks Journal of Geophysical Research 108, doi:10.1029/2001JB000661 Richter, B., Fuller, M., 1996 Palaeomagnetism of the Sibumasu and Indochina blocks: Implications for the extrusion tectonic model In: Hall, R., Blundell, D (Eds.), Tectonic Evolution of Southeast Asia, vol 106 Geological Society, London, Special Publication, pp 203–224 Please cite this article in press as: Cung, T.C., Geissman, J.W., A review of the paleomagnetic data from Cretaceous to lower Tertiary rocks from Vietnam, Indochina and South China, and their implications for Cenozoic tectonism in Vietnam and adjacent areas J Geodyn (2013), doi:10.1016/j.jog.2011.11.008 G Model GEOD-1103; No of Pages 11 ARTICLE IN PRESS T.C Cung, J.W Geissman / Journal of Geodynamics xxx (2013) xxx–xxx Ron, H., Freund, R., Garfunkel, Z., Nur, A., 1984 Block rotation by strike-slip faulting Structural and paleomagnetic evidence Journal of Geophysical Research 89, 6256–6270 Roperch, P., Fornari, M., Herail, G., Parraguez, G., 2000 Tectonic rotations within the Bolivian Altiplano: Implications for the geodynamic evolution of the central Andes during the Late Tertiary Journal of Geophysical Research 105, 795–820 Sato, K., Liu, Y., Zhu, Z., Yang, Z., Otofuji, Y.-I., 1999 Paleomagnetic study of middle Cretaceous rocks from Yunlong, western Yunnan, China: evidence of southward displacement of Indochina Earth and Planetary Science Letters 165, 1–15 Sato, K., Liu, Y., Zhu, Z., Yang, Z., Otofuji, Y.-I., 2001 Tertiary paleomagnetic data from northwestern Yunnan, China: further evidence for large clockwise rotation of the Indochina block and its tectonic implications Earth and Planetary Science Letters 185, 185–198 Stamatakos, J., Hirt, A., 1994 Palaeomagnetic considerations of the development of the Pennsylvania Salient in the central Appalachians Tectonophysics 231 (4), 237–255 Sun, Z., Yang, Z., Yang, T., Pei, J., Yu, Q., 2006 New Late Cretaceous and Paleogene paleomagnetic results from South China and their Geodynamic implications Journal of Geophysical Research 111, B03101, doi:03110.01029/02004JB003455 Sussman, A.J., Butler, R.F., Dinares-Turell, J., Verges, J., 2004 Vertical axis rotation of a foreland fold and implications for orogenic curvature: and example from the Southern Pyrenees, Spain Earth and Planetary Science Letters 218, 435–449 Takemoto, K., Halim, N., Otofuji, Y.-I., Tran, V.T., Le, V.D., Hada, S., 2005 New paleomagnetic constraints on the extrusion of Indochina: Late Cretaceous results from the Song Da terrane, northern Vietnam Earth and Planetary Science Letters 229, 273–285 Tapponnier, P., Peltzer, G., Le Dain, A.Y., Armijo, R., 1982 Propagating extrusion tectonics in Asia: new insights from simple experiments with plasticine Geology 10, 611–616 Tapponnier, P., Peltzer, G., Armijo, R., 1986 On the mechanism of the collision between India and Asia In: Coward, M.P., Ries, A.C (Eds.), Collision Tectonics, vol 19 Geological Society, London, Special Publication, pp 115–157 Tauxe, L., Kent, D.V., 2004 A simplified statistical model for the geomagnetic field and the detection of shallow bias in paleomagnetic inclinations: was the ancient magnetic field dipolar? In: Channell, J.E.T (Ed.), Timescales of the Paleomagnetic Field, vol 145 American Geophysical Union, Washington, DC, pp 101–116 Taylor, B., Hayes, D.E., 1980 The tectonic evolution of the South China Basin In: Hayes, D.E (Ed.), The Tectonic and Geologic Evolution of Southeast Asian Seas and Islands Part Geophysical Monograph Series, vol 23 AGU, Washington, DC, pp 89–104 Taylor, B., Hayes, D.E., 1983 Origin and history of the South China Sea Basin In: Hayes, D.E (Ed.), The Tectonic and Geologic Evolution of Southeast Asian Seas and Islands Part Geophysical Monograph Series, vol 27 AGU, Washington, DC, p 23-56 Tsuneki, Y., Morinaga, H., Liu, Y., 2009 New palaeomagnetic data supporting the extent of the stable body of the South China Block since the Cretaceous and 11 some implications on magnetization acquisition of red beds Geophysical Journal International 178, 1327–1336 Tsutsumi, H., Sato, H., 1930 Tectonic geomorphology of the southernmost Sagaing Fault and surface rupture associated with the May, 1930, Pego (Bago) earthquake, Myanmar Bulletin of the Seismological Society of America 99, 2155–2168 Van der Voo, R., 1993 Paleomagnetism of the Atlantic, Tethys, and Iapetus Oceans, First ed Cambridge University Press, Cambridge, 411 pp Van der Voo, R., Torsvik, T.H., 2011 The history of remagnetization of sedimentary rocks: descriptions, developments, discoveries In: Elmore, R.D (Ed.), Remagnetization and Chemical Alteration of Sedimentary Rocks Geological Society of London, London Vigny, C., Socquet, A., Rangin, C., Chamot-Rooke, N., Pubellier, M., Bouin, M.N., Bertrand, G., Becker, M., 2003 Present day crustal deformation around Sagaing Fault, Myanmar Journal of Geophysical Research 108 (B11), 2533, doi:10.1029/2002JB001999 Wang, E., Burchfiel, B.C., 1997 Interpretation of Cenozoic Tectonics in the right-lateral accommodation zone between the Ailao Shan shear zone and the eastern Himalayan syntaxis International Geology Review 39, 191–219 Xu, J.W., 1993 Basic characteristics and tectonic evolution of the Tancheng-Lujiang fault zone In: Xu, J.W (Ed.), The Tancheng-Lujiang Wrench Fault System John Wiley, New York, pp 1–49 Yang, Z., Besse, J., 1993 Paleomagnetic study of Permian and Mesozoic sedimentary rocks from Northern Thailand supports the extrusion model for Indochina Earth and Planetary Science Letters 117, 525–552 Yang, Z., Yih, J., Sun, Z., Otofuji, Y.-I., Sato, K., 2001 Discrepant Cretaceous paleomagnetic poles between Eastern China and Indochina: a consequence of the extrusion of Indochina Tectonophysics 334, 101–113 Yoshioka, S., Liu, Y.Y., Sato, K., Inokuchi, H., Su, L., Zaman, H., Otofuji, Y.-I., 2003 Paleomagnetic evidence for post-Cretaceous internal deformation of the Chuan Dian Fragment in the Yangtze block: a consequence of indentation of India into Asia Tectonophysics 376, 61–74 Zhai, Y., Seguin, M.K., Zhou, Y., Dong, J., Zheng, Y., 1992 New paleomagnetic data from the Huanan block, China, and Cretaceous tectonics in eastern China Physics of the Earth and Planetary interiors 73, 163–188 Zhu, Z., Hao, T., Zhao, H., 1988 Paleomagnetic study on the tectonic motion of Pan-xi block and adjacent area during Yin Zhi-Yan Shan period Acta Geophysica Sinica 31, 420–431 (in Chinese) Zhu, Z., Morinaga, H., Gui, R., Xu, S., Liu, Y., 2006 Paleomagnetic constraints on the extent of the stable body of the South China Block since the Cretaceous: new data from the Yuanma Basin, China Earth and Planetary Science Letters 248, 533–544 Zijderveld, J.D.A., 1967 A.C Demagnetization of rocks: analysis of results In: Collinson, D.W., Creer, K.M., Runcorn, S.K (Eds.), Methods in Palaeomagnetism Elsevier, Amsterdam, pp 254, 286 Please cite this article in press as: Cung, T.C., Geissman, J.W., A review of the paleomagnetic data from Cretaceous to lower Tertiary rocks from Vietnam, Indochina and South China, and their implications for Cenozoic tectonism in Vietnam and adjacent areas J Geodyn (2013), doi:10.1016/j.jog.2011.11.008 ... data from Cretaceous to lower Tertiary rocks from Vietnam, Indochina and South China, and their implications for Cenozoic tectonism in Vietnam and adjacent areas J Geodyn (2013), doi:10.1016/j.jog.2011.11.008... data from Cretaceous to lower Tertiary rocks from Vietnam, Indochina and South China, and their implications for Cenozoic tectonism in Vietnam and adjacent areas J Geodyn (2013), doi:10.1016/j.jog.2011.11.008... data from Cretaceous to lower Tertiary rocks from Vietnam, Indochina and South China, and their implications for Cenozoic tectonism in Vietnam and adjacent areas J Geodyn (2013), doi:10.1016/j.jog.2011.11.008