ESS104H1 Lecture Notes - Lecture 7: Central Atlantic Magmatic Province, Phanerozoic, Gamma Ray
Document Summary
Reading: causes and prime causes of mass biotic extinctions in the phanerozoic by. Changes of scales in biotic communities provide grounds to define geological periods. Transitions between periods are marked by partial extinctions and appearances of some organisms and taxa. Great extinction events: catastrophic extinctions resulting in the disappearance of ore than 75% of species. Extinction of 57% of genera and 86% of species. Responsible: alternation of glacial and interglacial episodes in southern. Gondwana , penetration of cold waters into deep basins, alternation of transgressions and regressions, and development of anoxia. Thought to be connected with gamma radiation burst. a. b. c. d. e. The great devonian extinction a. b. c. d. e. f. Eliminated 35% of genera and 75% of species. Responsible: greenhouse and glacial environments (ice shield in. Gondwana), sea level fluctuations and variations in co2 concentrations, and the development of deep-sea anoxia and its distribution to shallow depths during transgressions.
