A Look into the Past
Depositional conditions and structural deformation
The Austin Glen formation, which may be found at the Johnson Iorio Memorial Park, encompasses an abundance of clastic sedimentary rocks. More specifically, thin black shale and thick greywacke compose this formation. The thin black shale may be described as fine-grained and its color derives from lack of oxidation. This indicates the rock formed in deep ocean conditions. The shale layers are thin, and are approximately two to three centimeters wide. On the other hand, the greywacke shale, which is about fifteen centimeters, is thicker than the black shale. The greywacke is coarse grained, and a sandstone. The black shale and greywacke alternate between layers
The High Falls was deposited first, then the Binnewater, and, finally, the Rondout formation. The oldest formation, or the High Falls, consisted of thin red and brown mudstone. Through observation, it may be described as red shale. The rock is this color due to the presence of hematite and iron oxide. Therefore, it can be inferred this rock formed in a floodplain, where it was in an oxygenated system. Rivers must have deposited mud to form the red shale that is fine-grained. Proceeding the High Falls formation, the Binnewater formation consisted of a light tan rock that was a few centimeters thick. This was a clastic sedimentary rock with coarse texture. When tested with hydrochloric acid, the sedimentary rock reacted, therefore it may be defined as a quartz sandstone. The cement holding the rock together allows for a reaction. This layer formed in marine conditions. Finally, the Rondout Formation, or the youngest layer, consisted of a chemical sedimentary rock. This layer was grey and approximately five centimeters thick. It may be identified as dolostone due to its ability to react with hydrochloric acid in the powdered form. Dolostone has a microcrystalline texture. This layer formed in the environment of a shallow ocean. Additionally, this structure may be seen as a monocline. In other words, a shorter inclined limb connects two nearly horizontal limbs. Finally, this structure is approximately
These formations are part of the Helderberg group that may be aged approximately 416 to 359 million years old. The Becraft is on the bottom, therefore making it the oldest layer due to the principle of superposition. It contains fossiliferous limestone, which is a clastic sedimentary rock containing fossils. The color may be described as light grey, and it is the thickest layer of the three. The Alsen formation contains fossiliferous limestone as well. Based on this information, it may be inferred the environment where the layers formed was a warm shallow ocean. Like quartz conglomerate and the powered form of dolostone, fossiliferous limestone reacts with hydrochloric acid. Dissimilar to the Becraft and Alsen formation, the Port Ewen formation contained black shale and chert. While the other layers were formed in a shallow ocean, this layer was formed in a deep ocean. There is more fossiliferous limestone than black shale and chert. Chert has a microcrystalline texture, and similarly to the first structure, black shale is fine-grained. The Kingston area creates an anticline. An anticline is a fold where the limbs dip away from the hinge (Patwardhan). More specifically, these formations dip west then east with no bend or limbs. The older beds occupy the center of an anticline. Finally, the hinge is not horizontal. This means this is a plunging fold, and one side is higher than the
...J.C. (2004) Mylonites and Brittle Shear Zones Along the Western Edge of the Avalon Terrane West of Boston, NEIGC Field Trip Guide.
The Kimmeridge Clay Formation is the penultimate formation of the onshore British Jurrasic Succession. William Smith was the first to document this distinct formation on his map of 1815, and to name as the Oaktree Soil. In 1817, he gave the name Oaktree Clay for the layers of clay between the “Portland Rock” and “Coral Rag and Pisolite” but in 1816 Webster was the first to describe in details the formation and changed to the name now known as kimmeridge Clay Formation after the English village of Kimmeridge on Dorset’s “Jurassic Coast” a place frequently visited by fossil hunters. (Cox and Gallois, 1981).
The Don Valley Brickwork consists of many different layers of geological deposits, allowing us to observe and have a better understanding of how the sediments we see today are formed. The most bottom layer in the Brickworks are from the Georgian Bay Formation, and consists of grey- shale bedrocks. Fossils are often found in this layer and it is estimated that this deposit of sediments is around 445 million years old. Above the bedrocks is a thin layer of grey clay sand and gavels left behind by the Illinoian Glacier. This layer is called the York Till and occurred around 135,000 years ago. The next layer consists of a sandy deposit called the Don Formation, which is formed by the Sangamonian Interglacial Stage. Many plant and animal fossils are found in this layer due to warmer climate around 120,000 years ago. Above it lies the Scarborough Formation, which consist of clay and sand. This sediment likely occurred 115 - 106,000 years ago. The next layer above is the Poetry Road Formation, and consist of sand and gravel. This layer is likely formed during the early Wisconsin glacial substage around 106- 75,000 years ago. Higher is the Sunnybrook Drift which was formed 60 – 75,000 years ago. And on the surface, is the Halton Till, which was left behind by the final push of the Wisconsin Glacier.
Sedimentary rock from the older Silurian Period is further from the river banks (Geological map of Victoria, 1973). Mudstone, inter-bedded shale and greywacke depositions indicate the Maribyrnong River may have previously taken a different shape, and younger sediments have replaced the older sediments in more recent geological periods.
The site visited on this day was informally known as the Bedrock Knob (NTS grid reference: 120 342). It is in an area where patches of limestone and exposed bedrock are common. The bedrock is part of the Preca...
...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.
This sedimentary rock has hardened over the many years with sand shells, small pebbles, grains of sand and rocks of various sizes. In comparison to our 4.5 billion year old Earth, these sand shells might as well be brand new, when in reality they could be up to 1,000 years old. If the sandstone were to be replaced with calcite it would completely change the subclass of rock, it would then be chemical & organic limestone. The variation in sand stone is due to different rates of deposition and change in patterns of the sediment movement (Mc Knight, p. 384). These tightly compacted varying stones and shells will be weathered away by wind and waves over time and could eventually be reduced to a rock the size of your hand.
Ehlen, Judy, and R.C. Whisonant. 2008. "Military geology of Antietam battlefield, Maryland, USA—geology, terrain, and casualties." Geology Today 20-27.
Henry, C.D., Tyler, N., 1998, Geology of Big Bend Ranch State Park, Texas: Texas Parks and Wildlife Press, 72 pp.
Morton, J. W. (n.d.). Metamorphosed melange terrane in the eastern piedmont of north carolina. Retrieved from http://geology.geoscienceworld.org/content/14/7/551.abstract
Deviance is a natural part of and necessary for stability and social order in society, this according to functionalist theorist Emile Durkheim (MindEdge, Inc., 2016). Traditionally, society is generally successful in providing motivation for individuals to aspire for goals of some sort, whether through wealth, prestige or perceived power (Henslin, 2011). However, from a functional perspective, theories have been developed in identifying when lawful and equal access is not afforded to certain individuals in the process of obtaining such goals. This restriction and inequality to opportunity for access in the quest to achieve success is what is now referred to as structural strain theory, which was developed by sociologist Robert Merton (Henslin,
Natural stone arches are geological formations that occur when rock is exposed to substantial amounts of erosion , which over time forces the rock into the shape of an arch. Stone arches are among the most diverse of rock formations, not only because of the large area where they are known to be found, but also their complex ways of forming. Although many factors contribute to making natural stone arches so enthralling, one key role keeps and hones our constant attention: each and every stone arch every formed will fall. Despite the things we do know about stone arches, they are continuously changing and teaching us new things about them as well as the world around us.
Smithsonian National Museum of Natural History (2014). Burgess Shale Fossil Specimens. Retrieved May 2014, from http://paleobiology.si.edu/burgess/burgessSpecimens.html
There are several theories about how the Cambrian Explosion started. There were major changes in marine environments and chemistry from the late Precambrian into the Cambrian, and these also may have impacted the rise of mineralized skeletons among previously soft-bodied organisms. One theory as to what happened is that oxygen in the atmosphere, with the contribution of photosy...
By using the principle of superposition we can know that the layers toward the bottom are older than the layers toward the top. The rock body shown in the pictures attached, started out as one layer, as millions and millions of years passed more layers of sedimentary rock were placed on top of each other one after another, each layer was deposited at a later time than the one before it. The youngest layer is on the top, and the oldest layer is on the bottom. This principle was founded by the Danish anatomist Nicolas ...