Discussion Questions on Geology - Paper Example

Question 1: Age of the Earth

The age of the planet earth is the most controversial matter in the creation (biblically) or evolution (historically) debate. Currently, the thought of earth coming into existence 6000 years ago is often ridiculed by the atheists as well as Christians. Archbishop of Ireland in the 17th century, James Ussher, is greatly criticized for stating that the earth was created in 4004BC. Initially, people had accepted the theory of Ussher, but later they changed their belief through trusting the latest findings by mortal dating techniques. The latter results indicated that the world was created billions of years ago. Ussher claimed that the first day of creation was 23rd of October; this was an extreme suggestion considering no substantial evidence was present to support it. The allegations were based on the brilliant idea that Ussher used the Genesis 5 and 11 along with other Bible verses, he only connected the record to the final expatriation of Judah in 584 BC.

The theory of catastrophism has been revitalized through the detection of enormous meteorite impact structures and proof of mass extinctions in the fossil chronology. The most remarkable events were the asteroid impact separating the Cretaceous and Tertiary Periods approximately 65 million years ago which corresponds with the dinosaurs extinction. The result developed a thin coat of clay which is a rare element on Earth but very concentrated in meteorites and minerals that only develops due to his pressure.

The James Huttons Uniformitarianism ultimately replaced catastrophism, which stated that the world had a very history that could be comprehended by the presence of present noticeable processes such as weathering of rocks and erosion of sediment. This concept is mainly focused on emphasizing that the present is a result of the past. I think the earth is aged 11-13 billion years according to the Actualism concept.

Question 2: Mineral and Rocks

A mineral refers to a naturally existing inorganic solid which constitute a typical internal atomic organization and a distinctive chemical composition. The five features of the mineral are: naturally existing, inorganic, solid, unique chemical composition and ordered internal structure. The unique chemical composition is the phenomena where the chemical constitution of minerals differs within a precise, limited kind. The ordered internal structure is the state that the atoms in a mineral are organized in a systematic and repeating design.

In the comparison of minerals and rocks there several factors that differentiate them; scientific study (mineralogy-minerals, petrology-rocks), chemical composition, classification, uses among others. Rocks contain two or more minerals, the defining factor for the formation of a mineral in a rock mass is the chemical constitution, some minerals when essential elements are present in the rock. On the contrary mineral composition differs from one mineral to the other; some have high levels of carbonate while others elevated levels of oxides. The rocks are categorized depending on the mineral and chemical composition, consistency of the integral particles and processes for their formation while the mineral is classified about chemical composition

Igneous rocks are formed from the cooling of the molten materials (magma). Magma is located beneath the earth crust and is exposed to significant pressure and temperatures (12000C). As a result of the high temperatures and pressure variation, the magma shoots on the surface in the pattern of a volcanic eruption to form volcanic or extrusive igneous rocks. Intrusive rocks result from slow cooling of magma under the earths crust and solidify to form a rock like granite. Extrusive rock results from the spillage of molten material over the earths surface for example basalt.

Question 3: Volcanos

The internal of the earth is very hot and continually the heat leftover leaks towards the earths exterior. During its escape, its warms the radioactive materials which provide the energy for the volcanic action and heats the rocks inside the earths surface which gradually shifts to the surface in other cases the magma continues to move upward. The three main types of volcanoes are stratovolcanoes (e.g., Mt. Tambora), shield volcanoes (Newberry) and cinder cones (Paricutin). Stratovolcanoes also knew as a composite are formed at the subduction zones, where their eruptions are classically explosive and effusive. The magma is enriched with volatiles since the magma erupts as water is collected in water-soaked minerals and permeable basalt rock. The release of water pushes the molten material to the surface. The cinder cones are formed from the volcanic debris consists of pyroclastic material, those piles nearby and downwind the volcanic outlet. Shield volcano results from frequent lava flows forming a gently sloping surface and are created horizontally.

The eruptions of volcanoes affect the climate because they produce an assortment of gases and particles into the air. Some of these constituents for example ash and sulfur dioxide have a cooling result since they reflect the sunlight away from the universe. Others substances such carbon dioxide caused warming through the addition to the greenhouse effect. The increase of this warming material tremendously increases the temperatures of the earth which may affect the farming practices. Currently, there are an array of tools that are used to predict volcanic eruptions using the ones that have already erupted however the volcanos are different from each other. Therefore prediction of a volcanic eruption is not efficient.

Question 4: Weathering

Weathering is a phenomenon that refers to the disintegration or variations of rock in its natural or initial location at or close to the earths surface via physical, chemical and organic processes caused or altered by the wind. Weathering processes are significant in the rock formation since the big rock are fragmented to smaller rocks, the smaller rock is disintegrated to the minerals that constitute the rocks. Ultimately the primary minerals from the smaller rocks from the secondary minerals.

Sedimentary rocks result from the windswept other rocks fragments or remains of animals and plants. These particles pile in the low-lying regions (lakes, deserts or oceans) and are then reversed to rocks by compression of the overlying materials. The sedimentary rocks cover approximately seventy-five percent of the surface since they have a variety of fragments that lead to their formation.

Sedimentary can be used scientifically to given information on the history of the earth. Firstly the old current directions are firm from the ripple marks, flute marks, cross bedding and from the existence of coal deposits. Secondly, diverse past environments are designated by fossils: animals with four limbs and plants define ancient land parts; fish and other invertebrates disclose old water bodies parts. Economically, sedimentary rock is the source of energy source (natural gas, uranium, and oil), sand and gravel for construction purposes, limestone to manufacture cement, quartz sand to produce glass. Additionally, sedimentary rocks created salts, rock gypsum (make plaster) and rocks containing phosphate make fertilizer.

Question 5: Sedimentary Environment

The sedimentary environment is a part of the surface of the earth, for example, a lake or stream, where large volumes of deposits collect. The conditions of residue accumulation belong to the following setting: coastal, terrestrial and marine environments. Terrestrial environments are a result of water, wind and ice erosion, transportation and accumulation of residues on the land. There are mainly five terrestrial environments: volcanic, glacial, desert, lake and stream (are the most extensive terrestrial settings). Coastal environments occur where the land connects to the terrestrial and marine processes which result in multifaceted sedimentary environments. The marine environments include the continental shelf and deep oceanic environments. Continental shelf results from significant distance from the shore or reduced sediments movements with surging water depth.

Sedimentary structures refer to observable geographies within the sedimentary rock that arises at the time of deposition and signifies manifestations of the physical and biological activities that functioned in depositional environments. They include stratification occurs due to the stacking over each other of sediment layer and occurs in the measurements of hundred meters or submillimeter. Cross bedding is another feature that takes place at numerous scales and is noticeable in sandstone and conglomerates. Graded bedding is associated with turbidity currents which originate on the slope amid deep sea basins and continental shelves. Others features include ripple marks and mud cracks.

Sedimentary structures are useful since their (primary structures) abundance and size signifying the probability of transportation and depositional agents. Other structures like cross-bedding show orientations that are steadily related to the current movement direction. Fossil refers to the naturally conserved remains or traces of living things that existed in the geological past. Examples include Archaeopteryx lithographica (bird), Hylonomus lyelli (reptile) and Elginerpeton pancheni (tetrapod). Its possible for living things with the hard skeleton to become a fossil after one dies because the earthly through the action of scavenging animal and scattering by waves and current.