Mccormack, Mitchell (2012) All about devonian period and events. University Publications, Delhi, India. ISBN 9788132336983
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Abstract
The Devonian is a geologic period and system of the Paleozoic Era spanning from 416 to 359.2 million years ago (ICS, 2004, chart). It is named after Devon, England, where rocks from this period were first studied. During the Devonian Period the pectoral and pelvic fins of lobe-finned fish evolved into arthropods also became well-established. legs as they started to walk on land as tetrapods around 397 Ma. Various terrestrial The first seed-bearing plants spread across dry land, forming huge forests. In the oceans, primitive sharks became more numerous than in the Silurian and the late Ordovician, and the first ray-finned and lobe-finned bony fish evolved. The first ammonite mollusks appeared, and trilobites, the mollusc-like brachiopods, as well as great coral reefs were still common. The Late Devonian extinction severely affected marine life. The paleogeography was dominated by the supercontinent of Gondwana to the south, the continent of Siberia to the north, and the early formation of the small supercontinent of Euramerica in between. The period is named after Devon, a county in southwestern England, where Devonian outcrops are common. While the rock beds that define the start and end of the period are well identified, the exact dates are uncertain. According to the International Commission on Stratigraphy (Ogg. 2004), the Devonian extends from the end of the Silurian Period 4160 = 28 Mya, to the beginning of the Carboniferous Period 359.9 2.5 Mya (in North America, the beginning of the Mississippian subperiod of the Carboniferous) (ICS 2004). In nineteenth-century texts the Devonian has been called the “Old Red Age”, after the red and brown terrestrial deposits known in the United Kingdom as the Old Red Sandstone in which early fossil discoveries were found. Another common term is "Age of the Fishes", referring to the evolution of several major groups of fish that took place during the period.
| Item Type: | Book |
|---|---|
| Subjects: | Q Science > QE Geology |
| Divisions: | Electronic Books |
| Depositing User: | Esam @ Hisham Muhammad |
| Date Deposited: | 12 Feb 2023 06:49 |
| Last Modified: | 12 Feb 2023 06:49 |
| URI: | http://odlsystem2.utm.my/id/eprint/3989 |
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