Proterozoic

1. a) What are the major global events that occurred in the Proterozoic? (3) Three global events occurred during the Proterozoic: The oxygen revolution: During the Proterozoic, biotic system were being established, which gave rise to biomass of the prokaryotic organisms like the “benthic and planktonic photosynthesizing organisms” Due to the vast developing diversity of environment, organisms could well adapt to these various environments, which increased the input of oxygen on Earth. Hence

The Earth has been around for a long time. Humans have been around for a long time. America has been around for a long time. However, these long times are on vastly different timescales, and are not even close to being comparable to each other. To human minds, however, it would seem as though anything beyond the scope of their lifetime blends into a series of events on a page. The years before their birth sticking together into an amalgam of history, distorted beyond recognition. We place prominence

The Rise of Oxygen in Earth’s Early Ocean and Atmosphere discuss the changes of oxygen throughout Earth’s history. Chronological events in history that characterize major changes in ocean or atmospheric conditions are supported by varying methods of research. Intervals between 3.0 and 0.8 billion years ago that have significant proven evidence or promising ongoing evidence are discussed. For the purpose of this paper, the main topics to summarize will be based on scientifically proven information

Throughout the Earth’s 4.6 billion years of existence, there have been multiple events that mark geographical changes as well as biological changes. Each massive event, (such as a mass extinction) marks the beginning of an eon. An example of an eon is the Hadean eon and the Archean eon. Next are eras, which represents smaller events such as the Paleozoic era. Next are periods which are even smaller such as the Cambrian period. Finally the epochs are the smallest time classifications which subdivide

(dated at about 542 million years ago). This long stretch of time involved the transformation of the earth from a barren planet to one full of life. Three eons collectively comprise the Precambrian. These include the Hadean, the Archean and the Proterozoic. The Hadean eon was the first eon in earth’s history and refers to the birth of the solar system that occurred between 4.6 billion to 4 billion years ago. It began with a solar nebula, which consisted

The Proterozoic Westboro Formation (ca. 800 Ma), composed of massive quartzites and interbedded schists, is interpreted as a passive margin assemblage deposited on Avalon before the microcontinent rifted from Gondwana. The Westboro experienced various pulses of deformation and metamorphism during the Proterozoic. Of notable interest are 1-to-3-meter wide, N-NE striking, shallow dipping mylonitic zones exposed in and around the Breakheart Reservation in Saugus, MA. At one location blocks of eroded

about as pre-Cambrian rocks are poorly exposed, many have been eroded or metamorphosed and fossils are seldom found. The Precambrian has been divided into 3 Eons: 1.Hadean (4600-3800 mya of which there is no rock record) 2.Archean 3800-2500 mya) 3.Proterozoic 2500-570 mya. The present atmosphere is greatly depleted in Ne, Xe and Kr which are inert gases that should be preserved in the atmosphere. This suggests that the earth’s initial atmosphere was lost

Introduction With the use of detrital zircon dating, and minor use of authigenic monazite dating, estimations of age constraints can be applied to the Proterozoic basins on the south Australian island, Tasmania. Zircon minerals occur as a trace component in many sedimentary rocks. Therefore due to its widespread occurrence and its relative resistance to both mechanical and chemical weathering, which enhances its chance of survival through processes of transportation, dating methods through zircon

The formation of Earth, 4.5 billion years ago till the evolution of hard-shelled animals, about 500 million years ago, is called the Precambrian period. There are many events during this time that are specific and affect the Precambrian life. The earth was formed and the first tectonic plate arose and began to move which caused many variations on the earth conditions during Precambrian that affected atmospheric composition and oceans. The level of oxygen arose in the atmosphere which enabled the

western US geologists have documented passive margin deposits as young as of upper Paleozoic age or younger. Therefore, Hildebrand (2009, 2013) hypothesis faces deficiency to explain the thrusting of Roberts Mountain and the emplacement of the Proterozoic rocks over the rocks of Lower Paleozoic age. Thus, the western Cordillera have been converted to an active margin prior to 124 Ma which is contradict with Hildebrand’s hypothesis (2009, 2013). Hildebrand, (2009, 2003) attempts to integrate both