Snyder Hill Fieldtrip Report
地质学代写 There are numerous Palaeozoic age outcrops spread in the southern part of Basin and Range province of Arizona. These rocks and fossils..
Snyder Hill Fieldtrip Report 地质学代写
There are numerous Palaeozoic age outcrops spread in the southern part of Basin and Range province of Arizona. These rocks and fossils are a good source of geological research. Nonetheless, the rocks in the Permian in Southern Arizona are not well covered in geologic publications. An inquiry was needed to establish the type of fossils in Snyder Hill and their lithologic changes due to prevailing environmental conditions.
盆地的南部和亚利桑那州的兰治省分布着许多古生代露头。 这些岩石和化石是地质研究的良好来源。 尽管如此，地质出版物并未很好地覆盖亚利桑那州南部二叠纪的岩石。 需要进行调查，以确定斯奈德山的化石类型以及由于普遍的环境条件而引起的岩性变化。
A field study was conducted to acquaint the researchers with the types of fossils in the areas and at the same time be able to illustrate the various minerals and mode of their preservation in the three strata of the outcrop.
Geography Setting and Description of Outcrop in the Snyder Hill 地质学代写
The outcrop is at the southwest of the Tucson Mountains and between State Highway 86 between Kinney Road and Ryan Field (Bryant 1955). According to Bryant (1955), the outcrop consisted of Concha limestone on the lower formation and the Rain valley Formation on the upper side that made a cliff of 15 by 20 meters. According to Bryant and McClymonds (1961),
the lower part was made up of limestone and chert rocks. The rocks were dark grey and mostly made of silica, limestone and dolomite. The outcrop had massive bedding of up to 1 meter. The area was relatively rich with well-preserved fossils including Brachiopods, Echinoids, Sponges, Crinoids, gastropods, bivalves, and bryozoans.
On the other hand, the middle part of the outcrop was 10 meters thick with a ledge formation. It had medium-thick bedding that mostly consisted of limestone and silica. The main types of rocks were limestone, chert, and siltstone, which made the whole part have a light grey colour. The rocks were fine and coarse. 地质学代写
The region is relatively rich with poorly preserved fossils including Brachiopods, 地质学代写
gastropods, brachiopods, sponge, and thoron nautiloid.The upper part is the Rain Valley. It forms a cliff with a thickness of about three by 5 meters. It has thin bedding and samples indicated that traces of minerals like limestone, dolomite and silica. The types of minerals showed the principal rock types were limestone,
dolomite and chert and together made the outcrop part look light grey or brownish. The rocks were also coarse. There were few types of lowly preserved fossils in this part included echinoids, brachiopods, gastropods.Geological Setting Through Time and Regional Geology
The climatic conditions of deposition were warm tropical marine conditions (Rasmussen 2012). Evidence for the marine environment comes from organisms like sea urchins that only occur in marine environments. On the other hand, evidence for the warm tropical climate comes from limestone which is found throughout the outcropping limestone today mostly form in tropical seas. 地质学代写
腹足动物，腕足动物，海绵和托龙鹦鹉螺。上部是雨谷。它形成了一个悬崖，其厚度约为三乘五米。它的被褥很薄，样品显示出痕量的矿物，例如石灰石，白云石和二氧化硅。矿物类型表明，主要岩石类型为石灰岩， 白云石和石一起使露头部分看起来是浅灰色或棕褐色。岩石也很粗糙。这部分的低保存化石种类很少，包括棘突类，腕足类，腹足类。 沉积的气候条件是温暖的热带海洋条件（Rasmussen 2012）。海洋环境的证据来自仅在海洋环境中发生的海胆等生物。另一方面，温暖的热带气候的证据来自石灰岩，而石灰岩在整个露头的石灰岩中都发现了，这些石灰岩大多形成于热带海域
Moreover, various regions of the outcrop have different environments of deposition.
The deep grey colour in the middle part was a result of lower deposition and high content of minerals. The region lithologic features are as a result of a high energy environment with a high level of oxygen. The relatively high energy also accelerates the rate of weathering that expose inner layers of the rocks.
The deep grey of the lower part of the outcrop was an indication of a higher percentage of deposition and concentration of identified minerals. The upper part’s lithologic indicated low deposition and energy.
中部的深灰色是较低的沉积和较高的矿物质含量的结果。 区域岩性特征是高能量环境和高氧水平的结果。 相对较高的能量还加快了暴露岩石内层的风化速率。
The field study added to the existing knowledge about the Snyder Hill outcrop. Little was known on the lithologic of rocks and minerals along its stratigraphic sequence as well as how the environmental conditions have influenced the deposition. The findings, therefore, to the diverse knowledge of geology about southern Arizona.
现场研究增加了有关Snyder Hill露头的现有知识。 人们对沿地层序的岩石和矿物的岩性以及环境条件如何影响沉积知之甚少。 因此，这一发现使人们对亚利桑那州南部的地质学有了多种认识。
Bryant, D.L., 1955. Stratigraphy of the Permian System in southern Arizona. Unpublished M.S. Thesis, University of Arizona, Department of Geology, p. 1-3, 45-51.
Bryant, D.L., and N.E. McClymonds. 1961. Permian Concha Limestone and Rainvalley Formation, southeastern Arizona. AAPG Bulletin, v. 45; no. 8; p. 1324-1333.
Rasmussen, J.C., 2012. The geologic history of Arizona. Rocks & Minerals, v. 87, no. 1, p. 56-63.