EESB15H3 Lecture Notes - Lecture 17: Ordovician Radiation, Sea Level, Panthalassa
11 Dec 2017
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Document Summary
Radiation of the main phyla of marine invertebrates. Low sea levels during times of orogeny. The iapetus, rheic, panthalassa, and tethys oceans. Statistical way of describing the variability of biological diversity throughout history. Gobe: dramatic increase in the families of marine invertebrates. Mass extinction at the end of the ordovician. Small with low biomass, high population density. Stronger niche partitioning, more varied life strategies. Radiated in the ordovician during the great ordovician biodiversification event, but are not relatively rare. Granite is mostly made of quartz, plagioclase, and k-feldspar. Regulates long term concentrations of carbon dioxide on geologic timescales. Feldspars turn into clay minerals and ions that are wash into oceans. Figure 3: cambrian record in ontario - the potsdam sandstone. The potsdam sandstone has evidence of cambrian sediments. Preserved in the ottawa embayment, a failed rodinia rift valley. Laurentia was covered by an epicontinental/epeiric sea. Transcontinental arch was a connection of basins. Preserved stratigraphy is youngest at the center.
