The Mesozoic (or Middle life) Era The Mesozoic (or Middle life) Era started with the mass extinction of the Paleozoic Era, and ended with the extinction of the Cretaceous period (Levin). It includes the Triassic period from 251 to 200 mya, followed by the Jurassic period, from 200 to 145 mya, and finished with the Cretaceous period, from 145 to 65 mya (Levin). Pangea When the new era began, the supercontinent Pangea started to split into two, our modern North America being part of Laurasia first, then of Laurentia, when it split even more (Levin). The division of Pangea lasted around 150 my, into the Cenozoic Era (Levin). Tectonic events, orogenies, and resulting resources The Mesozoic era was a time of key tectonic and orogenic events …show more content…
in the formation of North America. In the East, the breakup of Pangea produced rifting and crustal expansion when Laurasia separated from what is now Africa (Levin). The Newark rocks are an evidence of it. In the West, a subduction zone existed and the region endured compressional forces there as the Laurasia plate was slipping under the Pacific one. Exotic terranes and volcanic islands collided with the continental plate and attached there too (accretion). These collisions produced orogenies such as the Sonoma orogeny in the Cordillera, in the west during the Triassic period. When the Sonoma orogeny pushed east, it formed the Nevadan orogeny in the Jurassic and Cretaceous Periods. The Jurassic period also saw the Sevier orogeny that became our modern Sierra Nevada Mountains. Finally, the Laramide orogeny made our Rocky Mountains (Levin). The tectonic events of the Mesozoic era produced a vast assortment of resources used today, whether it is the 19th century gold mines of California contained in Sierra Nevada batholiths; copper, zinc or silver from Idaho and Montana rocks; uranium deposited in the era’s continental sedimentary rocks in Colorado or Utah; or fossil fuels like coal, oil or natural gas stored from Colorado to Texas, Virginia or Alaska (Levin). Paleogeographic interpretations for North America in the Mesozoic Era. During the Triassic period: At that time, in the East of North America, the Appalachian were very high and volcanic eruptions were intense because of the rifting occurring (the palisades of the Hudson River) but starting to erode (clastic sediments with marine fossils in the Newark supergroup rocks). On the western side of the mountain range were lowlands with sedimentary rocks with fossils of fish, invertebrates and marine reptiles (Levin). In the western part of North America, the accretion is seen through volcanic and graywackes deposits. These are traces of the geologic past of the region with shallow water sandstones and limestones, proofs of a past continental sea; and eastward, continental beds deposits. When the sea regressed, the following erosion formed an unconformity (Levin). During the Jurassic period: In the Jurassic period, the craton was inundated by low seas, with deposits of shale and sand. The western part of North America witnessed regression and transgression of marine environment. The Navaro sandstones show proof of wind deposits in a coastal environment. The Jurassic also had the Sundance sea flooding the continent, with deposits of sand and silts rich in fossils of marine reptiles. As it regressed, it left a swamp, and the Morrison formation deposits, perfect environment for dinosaur fossils. The eastern part of the continent comprised the lower Appalachians and non marine deposits; in the south, limestones and evaporates were deposited, with beds of gypsum and salt in the region of the current Gulf of Mexico.
During the Cretaceous period: The Cretaceous period takes its name from the Latin word for chalk because that specific selection of limestone was deposited very widely at the time. The Niobrara formation was formed then, with a plethora of marine fossils. (Levin) The sea level was higher then and present day North America was under a huge epicontinental sea. Modern day Florida was under shallow water with deposits of carbonates over shales and sandstones. On the Atlantic Ocean side, the coastal plains started to cave in to become our current continental shelf, east of the eroding Appalachian. The reefs growing in the period’s warm climate led to a huge storage of various organic debris that were to become our current reserves of gas, oil and coal. (Levin) In the west, the Dakota sandstones are reminiscent of the transgression and regression of the Epicontinental Sea. Tectonic deformations and erosion continued as we see in folded and faulted rocks in the Rocky Mountains. Bentonite, present in that part of North America, proves the active volcanism of the time.
(Levin) Work cited: Levin, Harold. The Earth Through Time. 10th ed. Hoboken: Wiley, 2013. Print. Pictures chapter 13
Van Staal, C.R., Whalen, J.B., Valverde-Vaquero, P., Zagorevski, A., and Rogers, N. (2009) Pre-Carboniferous, Episodic Accretion-Related, Orogenesis along the Laurentian Margin of the Northern Appalachians. Geological Society, London, Special Publications, vol. 327, p. 271-316.
The Starved Rock Member of the Saint Peter Sandstone is preserved as a northeast-southwest trending belt of strata that is ...
...e morphed it into the quartzite that is seen surrounding the butte (4). Rocks that undergo this process are called metamorphic rock, which is the same as the rock seen years ago by dinosaurs and other extinct creatures. The quartzite rocks were formerly seafloor sediment that was forced upwards, and then surrounded by lava basalt flows. Once erupted through fissures and floods through out most of the area, lava flow eventually created enough basalt to form a thickness of about 1.8 kilometers (1). All of this basalt flow eventually led to the covering of most mountains, leaving the buttes uncovered. The igneous lava flows and loess is reasons that the Palouse consists of such sprawling hills, and rich soil for farming (2). In result of the lava flows, the Precambrian rock Quartzite was formed. And lastly covered by the glacial loess, which were carried by the wind.
The geological arrangement was largely influenced by the Western Interior Seaway, which swept through the continent millions of years ago. It was during this time when frequent alterations in climate caused the waters to surface and withdraw. The Dakota Sandstone deposited within the sedimentary profile of Mesa Verde is in large part due to these events.
The main theme in Rising from the Plains is the formation of the Rocky Mountains. “Topography grows, shrinks, compresses, spreads, disintegrates, and disappears” (McPhee 27). The physical features of the Earth are temporary and are always changing. The
Did you know, in the state of Oklahoma it is against the law to either hunt or catch whales? Sounds sort of ridiculous when you think logically about it, but according to paleontologists it isn’t that far fetched. Over 65 million years ago Kansas, including the whole Midwest Region of North America from the Arctic Circle to the Gulf of Mexico, was covered by the Sea. Due to the continental uplifts of the mountain ranges in North America during the Pangaea stage, the once shallow sea of Kansas became shut off from the sea-water flow and dried out to what we know it as today. The biome of Kansas over the last 65 million years has become extremely dry and flat, which would account for a once shallow inland sea. For example; Salt Lake City was once in the mist of a glacier that filled the inside “hole” of the City, causing the surface of it to be extremely flat excluding the surrounding mountains.
Paleolithic is often referred to as the Old Stone Age. "Paleo" means old and "lithic" means stone. The Neolithic time period is often referred to as the New Stone Age. "Neo" means new and "lithic" also means stone. The Paleolithic culture or way of life began about 2.5 to 2 million years ago. The Paleolithic Period ended at different times in different parts of the world, generally around 12,000 years ago in Europe and the Middle East. When the Paleolithic period ended, the Neolithic period took over and began 12,000 years ago somewhere in the Middle East, and later in other parts of the world. It is characterized by the beginning of farming, the domestication of animals, the development of crafts such as pottery and weaving, and the making of polished stone tools. Life changed dramatically between Paleolithic and Neolithic times.
"Sedimentary Rocks." Backyard Nature with Jim Conrad. N.p., 18 May 2015. Web. 25 Oct. 2015.
Americas by 14,000 ago” (O’Brien 12), after large portions of North America encountered the last ice age, which
The climate of the Pennsylvanian period is very different from that of ours today. The climate can best be described as being similar to a rainforest. “The Pennsylvanian was the time of the great ‘Coal Swamp Forests’ which dominated the equatorial regions of the planet.” (Kazlev) There were extensive swampy regions that stretched across countries. Much of the world was underwater and is what allowed some of the species that emerged to be so successful. Even though ...
Dinosaurs held their own, according to studies, for at least 150 million years. After becoming extinct and finding fossilized remains dinosaurs have become a way in which we not only measure the changes that have occurred as the planet evolved, but also how we express ourselves today.
Through all these changes America was able to emerge as their own. America now has been divided into many countries, but two continents (North and South America). The Americas have been divided culturally too (Anglo-Saxon America and Latin America). These formations of continents can be seen through the Christian cosmology. Then the “discovery” of America caused many things to change; such as the map and the transformation of the global economy. Finally the consequences of the West holding so much power created change in the rest of the world to occur.
The areas dominated by the Maya are known today as the southern Mexican states: Chiapas, Campeche, Yucatan, Quintana Roo, and Tabasco. The Maya civilization spread all the way through the nations of Guatemala, Belize, El Salvador, and Honduras. A very large expanse of city-states that ruled the area linked by trade routes.
The Permian Period occurred around 298 million years ago. It stretched from the Carboniferous Era to the Triassic. Sir Roderick Murchison in the early 1800’s noticed a differentiation among the overlay of the rock formation in the Ural Mountains in Russia. These rocks differed from the older Carboniferous rocks in Britain, and seemed younger than the Triassic rocks of Europe. Murchison named this differentiation after the prehistoric kingdom of Perm, thus the Permian Period.
The Paleolithic Period began 2.5 million years ago. This period is said to have began when the first evidence of tools constructed and used by humans were found. This period is often referred to as the Old Stone Age. It is characterized by the us of stone tools. These were some of the first tools used by humans, mostly used to hunt their food. However, tools such as spears and bones, used after killing an animal, were also used as hunting tools. The Paleolithic Period covers almost 95 % of the human prehistory. This is dated as far back as 3.3 million years ago when stone tools were made to about 6,000 years ago when the first writing system was created. During the Paleolithic Period, groups of people began to stick together. This is what became some of the first tribes. They traveled and hunted in groups of people, instead of just a few traveling together. They often would follow food, including the giant woolly mammoth. Then, “fifteen thousand years ago, Homo sapiens took advantage of land bridges exposed by lowered sea levels and spread to Indonesia, New Guinea, Australia, and, finally, the Americas,” (1). The groups of Hunter-Gatherers usually made houses of wood or hide. They weren’t very large