Topic%2017_Paleogene - Paleogene Period Paleocene Epoch The...

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Paleogene Period Paleocene Epoch The Paleocene, "early dawn of the recent", is a geologic epoch that lasted from 65 Ma to 56 Ma (million years ago). It is the first epoch of the Paleogene Period in the modern Cenozoic era. As with most other older geologic periods, the strata that define the epoch's beginning and end are well identified but the exact date of the end is uncertain. The Paleocene epoch immediately followed the mass extinction event at the end of the Cretaceous, known as the K-T boundary (Cretaceous - Tertiary), which marks the demise of the dinosaurs. The die-off of the dinosaurs left unfilled ecological niches worldwide, and the name "Paleocene" comes from Greek and refers to the "old(er)" (palaios) – "new" ( kainos) fauna that arose during the epoch, before modern mammalian orders emerged in the Eocene. Match left with right: ___Period A. Paleogene ___Epoch B. Paleocene ___includes Paleocene Boundaries and subdivisions The K-T boundary that marks the separation between Cretaceous and Paleocene is visible in the geological record of much of the Earth by a discontinuity in the fossil fauna, with high iridium levels. There is also fossil evidence of abrupt changes in flora and fauna. There is some evidence that a substantial but very short-lived climatic change may have happened in the very early decades of the Paleocene. There are several theories about the cause of the K-T extinction event, with most evidence supporting the impact of a 10 km diameter asteroid forming the buried Chicxulub Crater on the coast of Yucatan, Mexico. The end of the Paleocene ( 55 Ma) was marked by one of the most significant periods of global change during the Cenozoic. The Paleocene-Eocene Thermal Maximum upset oceanic and atmospheric circulation and led to the extinction of numerous deep-sea forams and a major turnover in mammals on land. Match ___Beginning of Paleocene A. K-T extinction ___End of Paleocene B. PETM Climate The early Paleocene was slightly cooler than the preceding Cretaceous, though temperatures rose again late in the epoch. The climate was warm and humid world-wide, with subtropical vegetation growing in Greenland and Patagonia. The poles were cool and temperate; North America, Europe, Australia and southern South America were warm and temperate; equatorial areas had tropical climates; and north and south of the equatorial areas, climates were hot and arid. Relative to the Cretaceous and Eocene, the global climate of the Paleocene was (cool, warm ). Relative to Geological history in general, the paleocene was ( warm, cool). Paleogeography In many ways, the Paleocene continued processes that had begun during the late Cretaceous Period. During the Paleocene, the continents continued to drift toward their present positions. Supercontinent Laurasia had not yet separated into three continents - Europe and Greenland were still connected, North America and Asia were still intermittently joined by a land bridge, while Greenland and North America
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This note was uploaded on 08/23/2009 for the course GEOL 102 taught by Professor Kennethsprenke during the Fall '09 term at Idaho.

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Topic%2017_Paleogene - Paleogene Period Paleocene Epoch The...

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