ERTH 2401 Lecture Notes - Lecture 18: Marine Reptile, Proganochelys, Platecarpus

• School: Carleton University
• Department: Earth Sciences
• Course: ERTH 2401
• Professor: Claudia Schröder-Adams

Document Summary

Bottom of ocean was anoxic so they could not survive there. Attached themselves to the wood which was floating so they could stay in the oxygenated zone. Eventually the wood gets waterlogged and sinks to the bottom, and anoxic sea floor, and are buried in fine sediments, beautifully preserving: different water densities causes stratified water column, causing the inhibition of vertical water movement. No oxygen gets to the bottom, causing anoxic bottom waters: crinoids were very abundant through the paleozoic, also around through. Mesozoic, and now are very rare but still exist. Jurassic in southern germany: over 60 million years europe partly covered by water forming smaller basins, stagnant water reduced oxygen exchange. Causing anoxic bottom water: an important fossil deposit is posidonienschiefer, a dark slate, lower jurassic rich in well preserved fossils. They broke off into the plesiosauria lineage which lived until the end of the cretaceous: placodontia were also an early group, around in the triassic.