Correlation of rock layers Earth Science 105 Geologic Time Chapter 11 Matching same age rocks In local area Across wide area In different regions Earth Science 11th ed Tarbuck Lutgens Grand Canyon Bryce Canyon Correlation of rock layers Zion Canyon Matching rocks of similar age in different regions Often relies upon fossils 1 Fossils evidence of past life Remains or traces of prehistoric life Types of fossils Petrified Formed by replacement Mold Cast Carbonization Impression Preservation in amber Indirect evidence Petrified Formed by replacement Cell material is removed and replaced with mineral matter Petrified Cavities and pores are filled with precipitated mineral matter Mold Shell or other structure is buried and then dissolved by underground water http www ammonoid com Manning html Shape is preserved in the surrounding sediment 2 Cast Hollow space of a mold is filled with mineral matter Impression Replica of the fossil s surface preserved in fine grained sediment Carbonization Organic matter becomes a thin residue of carbon This is a compression of the original organism Preservation in amber Hardened resin of ancient trees surrounds an organism Indirect Evidence Includes Tracks Burrows Coprolites fossil dung and stomach contents Gastroliths stomach stones used to grind food by some extinct reptiles Tracks Dinosaur footprint in fine grained limestone near Tuba City Arizona 3 Fossils and correlation Conditions favoring preservation Rapid burial Possession of hard parts Principle of faunal succession Principle of faunal succession Index fossils Geologic Time Scale Proposed by William Smith late 1700s Fossil organisms succeed one another in a definite and determinable order therefore any geologic time interval can be recognized by its fossil content Archean through Devonian http rst gsfc nasa gov Sect2 Sect2 1b html Carboniferous through Quaternary http rst gsfc nasa gov Sect2 Sect2 1b html 4 Cambrian Marine Life Trilobite http www ststephens it biology fossils html http www handprint com PS GEO geoevo html Crinoid 380 ma http www lsa umich edu exhibitmuseum exhibits temporary exhibits Ordovician Invertibrates Ordovician sea floor http www uwsp edu geo faculty hefferan Geol106 CLASS6 MAIN 20PAGE htm Silurian reef Silurian Reef http hoopermuseum earthsci carleton ca camex 1rpaleoreef html http www handprint com PS GEO geoevo html 5 Silurian Landscape http www nasa gov worldbook earth worldbook html Mid Paleozoic http www tufts edu as wright center cosmic evolution docs text text bio 4 html Carboniferous Fern Forests http www handprint com PS GEO geoevo html Devonian Sea http www handprint com PS GEO geoevo html Late Paleozoic http www tufts edu as wright center cosmic evolution docs text text bio 4 html Permian Reptiles http www handprint com PS GEO geoevo html 6 Permian Sea Geologic Time Scale http www handprint com PS GEO geoevo html Mesozoic Link to hypotheses of the Permian Extinction http en wikipedia org wiki Permian extinction http www tufts edu as wright center cosmic evolution docs text text bio 4 html Mesozoic http geography berkeley edu ProgramCourses CoursePagesFA2002 Geog40 Geog40 Week7 html Mesozoic http serc carleton edu introgeo earthhistory dinosaur html 7 Mesozoic http geography berkeley edu ProgramCourses CoursePagesFA2002 Geog40 Geog40 Week7 html Mesozoic Mammal Archeopteryx http www researchcasting ca sculpt 20miami htm Mesozoic Mammal Eomaia Repenomamus http www amnh org exhibitions dinosaurs diorama Jurassic http www worldbook com features dinosaurs html world mesozoic html http www amnh org science papers mesozoic mammal php Cretaceous http www worldbook com features dinosaurs html world mesozoic html 8 Mesozoic Sea http geography berkeley edu ProgramCourses CoursePagesFA2002 Geog40 Geog40 Week7 html Cretaceous Extinction Mesozoic sea http www uky edu AS Geology webdogs time mesozoic mesozoic htm Cenozoic mammals Perhaps 60 of species died Result of radical change in environment Perhaps Earth encountered a large meteorite 10 km in diameter 90 000 km hr Equivalent to 100 megatons of TNT exploding http www handprint com PS GEO geoevo html Cenozoic http www handprint com PS GEO geoevo html Cenozoic http www uky edu AS Geology webdogs time cenozoic cenozoic htm 9 Cenozoic Index fossils Widespread geographically Existed for a short range of geologic time http www copyrightexpired com Heinrich Harder cenozoic html Use of Index Fossils LABS MEET NEXT WEEK Bring your lab manual to every lab class Do the pre lab activity even if your instructor does not assign it Bring a calculator your textbook something to write with Next week we will be in NS 017 downstairs at the south end LAB TERMS Stratification Bed Stratigraphy Original horizontality Superposition Unconformity misspelled in lab book Cross cutting relationships Lateral continuity 10
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