Devonian

The early Devonian period is largely considered to be a world of a diverse array of lobe-finned fish, including lungfish, coelacanths, and bony fish. Over the course of time, vertebrates made evolutionary strides with provided them with the ability to travel on land. Coelacanths developed a single boned shoulder girdle, lungfish developed paired fins, and sauripterus developed the major structures on the arm (humerus, radius, and ulna). As these developments progressed and environmental pressures

The Devonian period initiating approximately 416 Mya and culminating 359 Mya represents a geologic time period, which characterizes a major part of the Paleozoic Era. Traversing between the Silurian period (444 - 416 Mya), and Carboniferous period (359 – 299 Mya) the Devonian period epitomizes substantial modifications in the world's ecology and geography. In the early Devonian period, also known as the Lochkovian, Pragian and Emsian epoch, due to substantial tectonic activity, resulted in the

At the start of the Devonian Period, about 419.2 million years ago, our planet was undergoing major change. The union of the paleo-continents of Laurentia and Baltica (made up of what is now parts of modern day North America, northern Europe, Russia, and Greenland) occurred near the beginning of the Devonian Period and formed a supercontinent that straddled the Equator. That landmass has been called Laurussia, or Euramerica. There was a great deal of red sediment created when North America collided

Precambrian Era The Precambrian era laster 4600-541 million years ago. During this time, there were no plant life on the planet. Most of the things that were on the planet were rocks. The most common type of rock was Isua greenstone. Most rocks have been eroded away, subducted, or metamorphosed. During this time, the atmospheres and oceans were formed, plate tectonics began to build up continental masses. The air during this time was mostly made up of water vapor, carbon dioxide, and nitrogen.

Melbourne has a bedrock of Middle Paleozoic age which is included within the Devonian and Silurian periods (354-441 million years prior). These rocks are overlain in wide zones which also include much more youthful rocks, and were generally part of the Tertiary and Quaternary ages (2-65 mya). Rocks of Early Silurian (441 mya) were discovered to be the most established within the bedrock. Particular in the outcrops located in the north-east around Warrandyte (Anderson Creek Formation), and on the

Abstract Late Devonian paleoclimate proxy records indicate substantial sea level variations, however a thorough understanding of the Late Devonian climate and the causes of these fluctuations remain uncertain. Numerous theories, including glaciation, bolide impacts, global anoxia, and the spreading of land plants are attributed to these events. This paper attempts to test the plausibility of the glaciation hypothesis by applying Late Devonian boundary conditions to a general circulation model (GCM)

Isotope anomalies across the Frasnian-Famennian extinction boundary: Implications for resolving Late Devonian mysteries Abstract The cause of the Late Devonian mass extinction near the Frasnian-Famennian boundary remains uncertain. Anomalies of stable isotope values have been observed at the Frasnian-Famennian boundary commonly, indicating the abrupt changes of environments during the crisis. These changes include marine anoxia possibly triggered by land plant evolutions, global cooling, and global

when a great number of species goes into extinction globally. The Late Devonian mass extinction is one the ‘Big Five’ mass extinction in history of earth which occurred 374.5Ma ago. This extinction event saw at least 70% of species perished; where main victim of this extinction event were the major reef builders, stromotopoids, rugose and tabulate corals (McGHee 2012). Causes of this mass extinction event during the late Devonian gathered a wide variety of debate throughout the years whereby researchers

During the Devonian period, most of the oceans were filled with stromatoporoids, brachiopods and corals. The Devonian period gave rises to some of the first tetrapods, amphibians, sharks, insects and boney fish. The first real land plants were also formed, giving rise to the first forest. The first plants were only about a foot tall and had no roots or leaves. By the late Devonian, plants had formed roots and leaves. The late Devonian Extinction was about 359 million years ago, and about 20 percent

members), Mule Spring Limestone, Monola Formation (lower and upper members), and the Bonanaza King dolomite (dominantly limestone and undivided). These Cambrian rocks are followed by rock layers from the Devonian period, thus meaning that an unconformity occurred between the layers. The Devonian dolomite rock layers include the Hidden Valley dolomite and the Lost Burro Formation (cherty dolomite). These are followed by the Mississippian