The Paleozoic metasediments seen in the Northern Appalachian cross section below

Question

The Paleozoic metasediments seen in the Northern Appalachian cross section below, were originally sediments that eroded from a large mountain range to the East. These sediments were metamorphosed when Europe and North America collided to form the Appalachian Mountains in the Late Paleozoic. If we were to construct a Late Paleozoic lithofacies map (see Lab 4) of this area, we would see an ocean to the west, and a large mountain range to the east, very different from the geography we see today. Using this information and the cross section below, answer questions 5-8. East West Taconic Mountains Connecticut Valley Pzc Pzi Hayden-McNeil, LLC Pe-Preca brian base en rock Lat, P€-Preca mbrian basement rock E:a:| -Triassic conglomerates and sandstones Pzc - Paleozoic carbonate rocks |^^A| -Triassic basaltic sills and dikes 52g P/ms - Paleozoie metasediments PZms - Paleozoic metasediments Pz Paleozoic diorite batholiths

Explanation / Answer

In North America, the era began with deep sedimentary basins along the eastern, southeastern, and western sides of the continent, while the interior was dry land. As the era proceeded, the marginal seas periodically washed over the stable interior, leaving sedimentary deposits to mark their incursions. During the early part of the era, the area of exposed Precambrian, or shield, rocks in central Canada were eroding, supplying sediment to the basins from the interior. Beginning in the Ordovician Period, mountain building intermittently proceeded in the eastern part of the Appalachian region throughout the rest of the era, bringing in new sediments. Sediments washing from the Acadian Mountains filled the western part of the Appalachian basins to form the famous coal swamps of the Carboniferous Period. In North America, carboniferous is not generally used. Instead, the time is divided between Mississippian and Pennsylvanian periods because of differences in the sedimentary rock deposited during that time. The Mississippian is characterized by limey sediments deposited in shallow seas, typically with abundant crinoidal fossils as in the Burlington Formation. The Pennsylvanian typically is characterized by terrestrial sediments such as sands, shale and most importantly coal. Most of our oil and gas are obtained from Pennsylvanian sediments. Where this has been stripped, as in the Ozark domal region, oil is not typically available.

Paleoclimatic studies and evidence of glaciers indicate that central Africa was most likely in the polar regions during the early Paleozoic. During the early Paleozoic, the huge continent Gondwanaland had either formed or was forming. By mid-Paleozoic, the collision of North America and Europe produced the Acadian-Caledonian uplifts, and a subduction plate uplifted eastern Australia. By the late Paleozoic, continental collisions formed the supercontinent Pangaea and resulted in some of the great mountain chains, including the Appalachians, Urals, and mountains of Tasmania.

There are three major types of rock: igneous, sedimentary, and metamorphic. The rock cycle is an important concept in geology which illustrates the relationships between these three types of rock, and magma. When a rock crystallizes from melt (magma and/or lava), it is an igneous rock. This rock can be weathered and eroded, and then redeposited and lithified into a sedimentary rock, or be turned into a metamorphic rock due to heat and pressure that change the mineral content of the rock which gives it a characteristic fabric. The sedimentary rock can then be subsequently turned into a metamorphic rock due to heat and pressure and is then weathered, eroded, deposited, and lithified, ultimately becoming a sedimentary rock. Sedimentary rock may also be re-eroded and redeposited, and metamorphic rock may also undergo additional metamorphism. All three types of rocks may be re-melted; when this happens, a new magma is formed, from which an igneous rock may once again crystallize.

The majority of research in geology is associated with the study of rock, as rock provides the primary record of the majority of the geologic history of the Earth.

Basaltic Sills:-

The Silurian spans from 443 million years to 419 million years ago. The Silurian saw the healing of the earth that recovered from the snowball earth. This period saw the mass evolution of fish, as jaw-less fish became more numerous, jawed fish evolved, and the first freshwater fish evolved, though arthropods, such as sea scorpions, were still apex predators. Fully terrestrial life evolved, which included early arachnids, fungi, and centipedes. Also, the evolution of vascular plants (Cooksonia) allowed plants to gain a foothold on land. These early plants are the forerunners of all plant life on land. During this time, there are four continents: Gondwana (Africa, South America, Australia, Antarctica, Siberia), Laurentia (North America), Baltica (Northern Europe), and Avalonia (Western Europe). The recent rise in sea levels provided many new species to thrive in water.

Dikes:-

Sedimentary dikes or clastic dikes are vertical bodies of sedimentary rock that cut off other rock layers. They can form in two ways:

Related Questions

Navigate

• Browse (All)
• Browse T
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.