Southern North Sea Basin Essay

It can be argued by some geologists that significantly more time is lost at bedding planes than is recorded by the accumulation of sediment and its later lithification into a sedimentary rock. In the present paper, the continuity of the sedimentary record is investigated. It is hypothesized that sedimentary strata preserved predominately records episodic sedimentation events and gaps represented by bedding planes symbolize more time than the preserved strata. The incompleteness of the geologic record and the role of rare events was studied using data gathered from a variety of sedimentary outcrops and cores. The author addressed his hypothesis using this collected data in terms of sediment preservation and represented preservation as a function of two modes of geomorphic processes: Magnitude and frequency. The author tested his hypothesis using relatively modern storm events to represent sedimentation, showing how daily processes can distort the geologic record, and by using ancient examples to illustrate how some storms can be preserved in spectacular condition.

One of the major things noticeable from the cross section is that quite a few of the rock layers are over turned, where the older rock layers are above the newer rock layers. This is seen in the contact between the Quartz Monzonite of Papoose Flat and the Campito Formation which is also a disconformity. Next there is some fault zones separating the Camptio, Poleta, and Harkless formations. We then see some more overturned layers with the contacts between Saline Spring Valley Formation (lower and upper members) above the Mule Spring Formation along with some inferred folding. With a normal fault separating the inferred folding event, we see where the overturning occurs. In between the Cambrian layers we see Tertiary Basalt nonconformities also being folded, thus with that we know that the folding event was more recent than the formation of the Basalt. Next there is a large Basalt field with a spot of the Harkless formation. Again we see over tuning as the Basalt field ends there are the Devonian and Mississippian rock Layers on top of the basalt. Separating these overturned layers from the Harkless Formation and the Saline valley Formation (upper member), which are not overturned, is a thrust fault. From this information, there was a major stress event sometime after the Tertiary period causing the rock layers to fold and overturn. And from this stress event and from the folding, normal and thrust faults are formed. Finally we see that there were alluvial and landslide deposits from the Quaternary after the folding, faulting, and over

Below these Carboniferous rocks, Devonian rocks are also exposed. These rocks can be found along the northern edge and southeastern margin of the plateau, where strata is nearly vertical. These two geologic systems have also been subdivided into numerous formations categorized according to their lithologic aspect and the fossil fauna and flora which they

The western Cordilleran orogenic belt had been depicted as a passive margin after Neoproterozoic to Early Cambrian rifting. Afterwards, the passive margin converted to an active margin most probably about Late Devonian to Late Cretaceous through the subduction of the exotic allochthons beneath the North American plate. The late Jurassic to Cretaceous subduction of (Sevier and Laramide Orogeny) representing as a period of the back thrust, intraplate thrusting, behind a magmatic arc on the upper plate near or on its westernmost margin from the latest

The South Brae oilfield is mainly Kimmeridgian to mid-Volgian in age, however on some accounts it may possibly be of Oxfordian (Turner et al, 1987). The oilfield is heavily developed along the western, fault-bounded margin of the South Viking Graben approximately 161 miles NE of Aberdeen flanking Fladen Ground Spur (see Fig.1). The Upper Jurassic rifting of the South Viking Graben encountered, pronounced movement along the western bounding fault as syn-rift extension proceeded (Harris & Fowler, 1987, Gregory et al, 2007). Syn‐tectonic deposition throughout the Jurassic ensued the formation of a distinct sediment wedge thinning eastwards into the basin, outlining the main phase of fault movement down the boundary fault (Roberts, 1991). As a result, the Brae oilfields are a series of

These Paleozoic rocks are steeply plunging sandstones and siltstones, with a little event of limestone at Lilydale - the Early Devonian Lilydale Limestone. The Silurian rocks were stored in profound water, while the Devonian rocks, which are exceptionally fossiliferous, appear to have been stored in shallower water. These Silurian and Devonian rocks were folded into a progression of anticlines

Another rifting phase started in the early Jurassic around Pliensbachian or Toarcian (Chongzhi et al., 2013; Geoscience, 2014; Tindale, Newell, Keall, & Smith, 1998). Exmouth, Barrow, Dampier and Beagle Sub-basins were created until Middle Jurassic (He, 2002; Tortopoglu, 2015) and oceanic crust was laid down to form the Argo Abyssal Plain in Late Jurassic around 164-160 Ma during the Callovian to Oxfordian then followed by the Gascoyne and Cuvier Abyssal Plain in Early Cretaceous around 125 Ma (Fullerton, Sager, & Handschumacher, 1989; Müller, Mihut, & Baldwin, 1998). Passive margin was established in North West Shelf. Rifting phase of the basin transformed into sagging phase post breakup thermal subsidence when Gondwana breakup took place during Valanginian early Cretaceous around 134Ma. During the Campanian late Cretaceous, rifting along the Australian southern margin triggered the basin inversions and wrench reactivation of basin structures on NW Shelf. These movements arose the Barrow Island above sea level and formed Novara, Resolution and Exmouth Plateau Arch in Barrow, Dampier Sub-Basins and Investigator Sub-Basin (Figure 1) (Longley et al., 2002; Sinhabaedya,

The Crato Formation lithologies were most likely deposited when there was a marine transgression; which is what the Cretaceous period is renowned for (Hu et al. 2012). The build-up of laminated limestones and different lithologies in the stratigraphic column could suggest that it was a lagoon depositional environment (Martill and Frey, 1998).

British Colombia in Canada, much like California in the United States, used to be a shallow sea and home to much sea life and is now home to thousands of marine animal fossils. For this reason it is believed that Dinosaur Provincial Park consisted of a lot of sands and muds that are characteristic of costal plains (Sues, Henderson, & Tanke, 2010, pg. 1292). When Sues, Henderson, and Tanke (2010) where going about measuring fossil shifts and the amount of fossils that have been lost they took into account the amount of soil that erodes away every year, the vertical and horizontal distribution fossils found within the park, and large landmarks such as rivers and glaciers that could effect fossils in the area (pg.1293). Accounting for these factors

The central idea of this article is the study of the Storr Lochs Monster and how its study can be applied to more fossils being found and studied in Scotland and in the Middle Jurassic Period. The author states that very few fossils can hunted down and studied in Scotland, and in the rest of the world fossils from the Middle Jurassic Period, when this creature lived, are very rare. Steve Brusatte, the Paleontologist from Scotland, said "We know that quite a lot was happening during the Middle Jurassic Period" he also said "It's frustrating because it seems like an active period in evolution but one with very few fossils" and also inputted that he hopes after the study of the Storr Lochs monster that an increase in Scottish paleontology can

Deposition of sediments began in the basin during the Cambrian era, but subsidence and basin filling occurred the most during the Ordovician,

Cape Lieper and Cape Ingersoll formations: They are part of Ryder Gletscher Group. They are mainly composed of dolomites and other carbonates rocks and they overlie Dallas Bugt Formation with thicknesses of up to 40m (Higgins et al, 1991). Other smaller formations within the Ryder Gletscher Group include Lower-Middle Cambrian wulff River and Cape Wood formations and they are mainly dominated by irregular bedded micritic limestone with thickness of up to 150m (Higgins et al, 1991). Cape Kent Formation of Lower Cambrian which was probably formed in a high-energy depositional environment in shallow water contains oolitic limestone with thickness of up to 10m

The Brent group is capped by the Humber group which can be sub-divided into the Heather and Kimmeridge Clay Formations, both of which are deep marine mudstones. Separating the formations and atop of the Brent group are unconformities attributed to the extension of the North Viking Graben and rotation of the Strathspey fault block during the late Jurassic. The thickness of this unit varies across the field; at the crest where erosion was greatest it can be less than 20 ft thick but increases to 300 ft towards the western hanging wall of the Ninian-Hutton Fault (Knox and Cordey,

These techniques led to the discovery of the boundary between the two eras. A single thin layer of clay found within predominantly limestone rocks established this. By comparing the marine life found in, above, and below the clay, the marine life, like the dinosaurs, had been terribly affected by the extinction event. The percentage of life in the upper layers was dramatically lower than that in the lower. This was far more compelling than what was suggested by dinosaur’s fossils.

The study of subduction initiation can be categorised into five model classes, the first exploring the formation of a subduction zone at a passive margin. Cloetingh et al. [1982, 1984, 1989] examined the environments that lead to the formation of a subduction zone from a passive margin. Their results revealed that subduction was achieved due to sediment loading if the oceanic plate was younger than ∼20 Myr. There results also suggested that the aging of the plate was detrimental rather than beneficial to the initiation of subduction. Regenauer-Lieb et al. [2001] also studied the formation of a subduction zone due to sediment loading at a passive margin. They suggested that water weakening of olivine promoted failure of the lithosphere and onset of subduction along Atlantic type continental margins. Nikolaeva et al. [2010] investigated the factors that control passive margins. Their results showed that incipient subduction at passive margins occurred with thin continental crust, elevated lithosphere temperatures and when negative buoyancy of the lithosphere is achieve (>20 Myr). Baes et al. [2010] analysed subduction transform edge propagator (STEP) faults, originating from a tear in the oceanic slab, using a thermal-mechanical model. Their results show that STEP fault-perpendicular convergence results in a dipping shear zone in any tectonic setting, resulting in a subduction zone at an oceanic-continental boundary after persistent convergence. Their results show that the