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FLOODS, FOSSILS AND HERESIES “NO VESTIGE OF A BEGINNING, NO PROSPECT OF AN END”JAMES HUTTON James Hutton Father of Geology Pre Age of Enlightment ❧Bishop Ussher 1654 ❧Biblical Chronology Based on generations ❧Earth created on October 23, 4004 B.C at 9AM ● FOSSILS ❧ Recognizable evidence of pre-existing life ● ● ● ● ● ● ● Perfect preservation of organisms Impressions- casts and molds Shells- original or replaced Bones- original or replaced Plant structures- trunks, leaves Trace fossils- tracks, burrows, borings Fecal matter (coprolites) Da Vinci’s Insight ❧ In 1500 C.E Leonardo Da Vinci recognized that fossil shells in the layered rocks represented ancient marine life ❧ Observed that many fossil rich layers were separated by unfossiliferous layers thereby repudiating the concept of one flood ❧ Had the idea that seasonal events responsible Nicolas Steno ❧ Danish Naturalist and Physician working for the Duke of Tuscany ❧ Widely circulated writings ❧ Fossils formed together with the rocks in which they occur ❧ 1669 stated the most basic principles ❧ Stratification- horizontal layering ● Inferred that differences in strata reflected differences in conditions (temperature, wind, currents, storms) Principles Used to Determine Relative Age- Nicolas Steno ❧Original Horizontality● Because particles settle from fluids under gravity, stratification MUST be horizontal ❧Superposition ● Progressively younger from bottom => top ❧Lateral Continuity ● Strata originally extended in all directions until it thinned to zero or terminated at margin (basin of deposition) Unconformities A) Angular Unconformity B) Nonconformity C) Disconformity STRATIGRAHY ❧ The study of layers of sedimentary rocks ❧ The study of rocks lithostratigraphy ❧ The study of fossil content biostratigraphy Correlation of Lower Cambrian rock units in western Montana C, B, G and A are trilobite index fossils Sedimentary Facies developed in the sea adjacent to a land area Front face shows shifting of facies through time Sedimentation during a regression: Coarsening Upward Sequence Walther’s Law- The vertical progression of facies will be the same as the corresponding lateral facies change A rise or fall in sea level will affect a far greater area along a low coastline than along coastlines composed of highlands that rise steeply adjacent to the sea The Vail sea-level Curve: Changes in Global sea-level through time Standard Geologic Time Scale ❧ Established in the 19th century- Developed by J Phillips 1840 based on work by Sedgwick & Murchinson ❧ Based on Fossil Assemblages ❧ Eons, Eras, Periods, and Epochs ● PHANEROZOIC since 544 m.y.b.p • Paleozoic Era 544-245 m.y.b.p • Mesozoic Era 245-65 m.y.b.p • Cenozoic Era 65 m.y.b.p.-present – Tertiary & Quaternary Periods » Recent (Holocene) Epoch last 10,000 years ❧Precambrian- All time before Paleozoic http://www.athro.com/geo/timecalc.html [...]... [fossils] and assigned to each its class and peculiar stratum” ❧ 1815 Publication of the 1st geologic map of England intended for the development of canals, quarries and mines as well as natural resources William Smith’s "Strata Identified by Organized Fossils" ❧ Soon after the first issue of his great geological map of England in 1815, William Smith published the Strata Identified by Organized Fossils. .. of Fossils ❧ John Woodward 1723, Correlation of strata in England and European mainland based on “great numbers of shells” ❧ Geologic Mapping ● 1746, crude geologic map showed continuity of chalk beneath the English Channel ● William Smith, canal engineer ❧ The Map that Changed the World, ❧ 1796 wrote “wonderful order and regularity with which nature has disposed of these singular productions [fossils] ... users manual with illustrations to identify fossils ❧ But Smith’s work went beyond the mere illustration of fossils Smith had deciphered the hieroglyphics of nature-the distinctive inscriptions borne by the different strata With the Strata Identified and its colored plates in hand, anyone would be able to compare the plates with fossils collected in the field and immediately identify the strata from... strata-which lay above and which lay below, as Smith had determined it was then known All this, Smith wrote, "without the necessity of deep reading, or the previous acquirement of difficult arts." Georges Cuvier and Alexandre Brongniart- Paris Basin ❧ Development of geologic map of Paris Basin ❧ The strata of the Paris Basin were close to horizontal As of ❧ 1811, Cuvier and Brongniart employed fossils but only... change through time- Charles Darwin Unified Hypotheses of the Earth ❧ Cosmogonists ● Human search for understanding ● Understanding God through his work (Nature) and his word (Scripture) ● All inclusive hypotheses to explain origin of universe, earth and life • Earth originally hot, cooled, water and atmosphere began segregated, interior still hot ❧ Buffon ❧ Geologic Chronology Buffon ❧ 18th century thinker... which they meant the distribution of what Werner had called the "external" characteristics of the mineral and fossil contents, shapes, colors, and textures of the strata within the Paris basin ❧ Today call this lithology They determined the order of the strata from their superposition, their lithology and by tracing them across the basin ❧ Cuvier firmly established the fact of the extinction of past lifeforms... of creation, “a year is to God as a thousand years to man” Geologic Chronology ❧ Buffon’s speculative chronology- 6 distinct epochs ❧ Recognition of rock divisions (coal measures in England by 1719) ❧ J Lehmann distinguishes gently dipping stratified fossiliferous rocks from more ‘primitive’ deposits ❧ 1759 Arduino distinguished Primitive, Secondary, Tertiary and Volcanic Neptunism ❧ A.G Werner (1787)... retreating ocean ● Neptunist ● Primitive, Transition, Secondary and Alluvial ● Considered earth to be static ❧ Basalt Controversy ● Volcanic rock ● Seen to crystallized from lava ● Could not be from a neptunian origin James Hutton and Plutonism ❧ Dynamic Earth ❧ Earth ever changing ❧ Modern earth processes capable of having produced landscape given enough time ❧ Geologic processes act slowly ❧ Interpretation... of the extinction of past lifeforms Correlation ❧ Physical Continuity of Lithologic Units ❧ Similarity of Rock Types ❧ Superposition ❧ Correlation by Fossils ● ● ● Principle of Faunal Succession Index Fossil Fossil Assemblage Correlation ❧ Correlation by Fossils ● Principle of Faunal Succession • Wm Smith & Georges Cuvier • Organism succeed one another in lithologic strata • One organism will NOT be... rocks of widely different ages ● Index Fossil Easily recognizable/Easily identifiable • Wide geographic distribution • Of limited life span as a species • ● Fossil Assemblage Explanation of Change Among Fossils ❧ Catastrophism ● ● ● Cuvier firmly established the fact of the extinction of past lifeforms Believed in wholesale catastrophic events caused extinctions With each catastrophe life move progressively
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