The geology of Sicily has a long and complicated history originating during the Mesozoic. The features that compose the present-day Mediterranean is a result from two major processes: the subduction of the African plate underneath the Eurasian plate, and the closure of the Mediterranean Sea. Deposits of carbonate sediment and marine organisms that were deposited from the Tethys Sea (Late Triassic to Early Cretaceous), make up the oldest exposed rocks of western Sicily. During this time, the area’s structural setting was largely dominated by transtentional plate movements which resulted in fault block morphologies with alternating horst and graben structures and east-west trending normal fault systems (Hsu and Bernoulli, 1978; Nigro and Renda, 2002). The structural setting had a strong impact on the depositional environments including: shallow-water elongate platforms, seamounts, and deep water basins. The depositional environments at the time were largely influenced by tectonic setting changing multiple times during the Late Jurassic into the Late Cretaceous. Between the Late Jurassic and Early Cretaceous the regions tectonic setting changed from a transtentional system to a strike-slip system. This period is characterized by deep limestone deposits and shallow to intertidal seamounts and platform calcarenites (Catalano et al., 1998; Cirilli et al., 1999; Bellanca et al., 2002). In the Late Cretaceous, there’s a change from the strike-slip phase into an extensional phase, along with the normal faults of the African paleomargin becoming reactivated, possibly due to the change in motion between the African and European plates (Tortorici et al., 2001). Basin sedimentation continued into the Late Cretaceous following the normal fa... ... middle of paper ... ...f the streams and drainage basins were found using the Calculate Geometry tool in ArcMap. This information gave us the minimum, maximum, average, and total stream lengths, along with the area of the drainage basins. Once this information was obtained it was used to calculate morphometric relationships (table 1). The sinuosity of the BRV was determined through a custom built tool in ArcMap that took the length of the stream over the length of the valley. After the morphometric parameters were calculated, a multi-ring buffer was performed around the Stretto. This essentially created rings of a specified distance (500 m in this case) around a point of interest (the Stretto). The purpose here was to gain a better understanding of the actual distance from the Stretto to the BRV in order to see how feasible it would have been to travel by foot to the BRV for resources.
The shelf-edge includes carbonate-to-clastic facies transition and tectonic uplift and erosion of the carbonates followed by deposition of the clastics. The Saint Peter Sandstone is a well-sorted, almost pure quartz arenite deposited during a major mid-Ordovician low stand. Clastics spread across an exposed carbonate platform by transportation. This is shown by the well-rounded, frosted texture of the quartz grains.
The sediments of the Kimmeridge Clay Formation were deposited during Late Jurassic between around 160 and 145 million years ago. The outcrop and subcrop from Kimmeridge Clay in England extends from Dorset to North Yorkshire but due to the lack of exposure inland, all stratigraphic studies of the formation has occurred in the costal sections between Weymouth and Swanage in Dorset ( Figure 1) (Cox and Gallios, 1981)
A compressive tectonic activity of the orogenic belt carried on in the eastern portion of the basin into the late Tertiary and the northern structural margin of the basin was part of a rifted margin of an oceanic basin. Through seismic sequence analysis the normal faulting in this area is believed to be active from the middle Jurassic to the early cretaceous. The North Slope developed on a south facing continental margin which was Paleozoic to Mesozoic in age. Both the rifting in the north and the compression in the south margin make the North Slope foreland basin. The evolution of the basin is known from the fragments that were preserved in the Brooks Range orogene and archives many kilometers of crustal shortening in the early stage. Later on during the Aptian to the Holocene on records a miniscule amount of crustal shortening that were created by an adjacent orogeny during earlier basin development. There are shifting sites of deformation are thought to be produced by northeastward filling of the basin. The basin as we see it today is thought to have begun to form in the Aptian time. There was major subsidence which is a change in deformation had depressed the south facing shelf. The eastern end of the basin subsided during the Tertiary time more than likely due
Study the method for constructing a topographic profile in Figure 6-4. Using this approach, construct a topographic profile on Figure 6-6. Before completing the profile,
During the Jurassic period, Pangea began to break up and by the time of the Late Cretaceous, ~94 Mya, the Atlantic Ocean began to open and Pangea continued to break apart. Due to this breakage of continents, there were extreme volcanic activity and much evidence can be seen of this all around the world today. In Anglesey, there are many igneous dykes and sills that have intruded older rocks that have been dated back to this time. This movement of continents continued into the Cenozoic era which is the current and most recent geological era consisting of the past 65 million years. It was during this time that Anglesey reached its current, present day
The rate of seafloor spreading was minimal during the Ordovician Period but thanks to high oceanic ridges, the seafloor became elevated and many parts of the continents were flooded. Shallow seas within the continents were thus formed. Sea levels fluctuated constantly maybe due to the rates of plate motion, ice caps, etc. The major tectonic plates were moving during this period so volcanism was extensive, peaking twice during the early Paleozoic Era. Mountain building belts were created wherever plates converged as well.
The sediments on the Arrastre wash were deposited in the alluvial environment, in other words, by a river that passed through the region during the Cretaceous. Moreover, they were initially horizontal, but stresses, which could be caused by the increase in pressure and temperature or even the movement of the tectonic plates, forced the layers to fold. In addition to the folds, it was possible to observe the ripple marks on the floor of the Ripple Wash, which gives the direction in which the river was flowing, and joints on certain
The Permian Period was the last period of the Paleozoic Era. During this geological time period’s earlier stages glaciation was extensive. Middle Permian began to warm, and by the late Permian the environment was hot and dry. The environmental conditions were so extreme that the marine and terrestrial life forms were greatly affected. According to research the drastic climate change could have been caused by the formation of Pangaea. In 1912 Alfred Wegener while studying his theory of the continental drift, discovered Pangaea’s very existence. A combination of all of Earth’s landmasses joined together and covered 1/3 of Earth’s surface. Pangaea was f...
...t of laurasia, just like most of the other plates. North America,Europe, and Green land all used to be connect because of Pangea ( as mentioned earlier). But when everything started to separate, first europe, then green land, and lastly the North American plate. After pangea was no more and the plates all started moving, the continents started going their own ways, there fore putting the continents where they are today.
... used to be a sea (Beaumont,1978). As mountain-building forces continued for several million years it created a big fold or anticline as it squeezed the rocks. These same pressures continued and overturned the fold which eventually caused them to break along a great low-angle fault (Beaumont,1978). The western limb of the fold was driven upward and eastern placing older layers of rock on top of younger ones. The younger layers of rock include cretaceous shales and sandstones. The slice of crust has been moved more than 15 miles toward the east, the surface it moved through is called the Lewis Overthrust. (Dyson,1957). Years of erosion finally exposed the fault which was buried throughout its early years. Erosion then separated several remnants, Chief Mountain is the best known which consists of Altyn limestone, exposed on its base is the Lewis Overthrust fault.
The Burgess Shale formation is characteristically informative of significant events in the evolutionary path of multiple organisms. Its abundance of exquisitely preserved Lagerstätte has inspired paleontologists to refer to this mode of preservation as ‘Burgess Shale-type’ (Williams, 2009).
Zhou, Z., Barrett, P., & Hilton, J. "An exceptionally preserved Lower Cretaceous ecosystem." 421. 20 February 2003: 807-814. 4 April 2004 <www.nature.com/nature>.
"Sedimentary Rocks and the Rock Cycle." South Carolina Geological Survey, n.d. Web. 2 Dec. 2013.
The determination of the textural maturity of a sediment is independent to its composition as it is influenced largely to its depositional processes, although it can be altered by diagenetic processes (Tucker 2001, 11).
Khramov (1985) was the pioneer who used both volcanic and sedimentary rocks to develop a single geochronogica...