GEOL 105 Study Guide - Midterm Guide: List Of Index Fossils, Periscope, Biostratigraphy

• School: College of Charleston
• Department: Geology and Environmental Geosciences
• Course: GEOL 105
• Professor: Dr. Robert Boessenecker

Document Summary

Cambrian (541-485 ma: earliest period of phanerozoic eon, extant phyla appear, earliest carnivorous animals, first skeletons, no land plants/animals-microbial crusts only, numerous fossil assemblages with excellent preservation of soft tissues. Base of the cambrian: cambrian series named by sedgwick in 1835 in wales, uk, originally defined as lowermost occurence of complex life-usually trilobites. Trace fossils-ichnology: fossilized behavior -most common type of fossil, traces given luteinized binomial names, tenet 1: multiple organisms can produce the same trace, tenet 2: a single individual can produce multiple traces. Archaeocyathids: first reefs: relationships unknown-either completely extinct phylum, or possibly early sponge, first reef-building organism" small patch reefs, diverse in early cambrian, decline during mid-late cambrian. Beach deposits: planar laminated sandstone: beds, ground surface is flat; no cross-bedding. Shoreface: low tide line to fair weather wave base: ripples, can deposit trough cross-bedding. Hummocky cross-bedded sandstone: deposited after a storm. Laminated siltstone: interbedded with shale and thin sandstone.