The Role Of Active Faults On Fracture Development

With our observation of the Shawangunk formation, we see a sedimentary rock formation containing a range of grain size. Such sizes range from pebbles (3cm-5cm), fine-grain sand, and medium-grain sand. There is some grading towards the bottom left of the outcrop known as a reverse grading with some small cross beds present (Figure 2). The grading occurs towards a slight part of the outcrop where we see the grading beginning as fine grain sediments and working up to coarser grain. With moderate sorting we see variations of degree of sorting per bed. As the degree of sorting varies as does the sphericity. The sediment bedding is well seen ranging in sizes of +/--20 cm to 40 cm. This outcrop has thick beds as one can see the basic units with cracks in between each (Figure 3). With mostly tabular beds consisting of sub-angular, and sub-rounded sediments, this outcrop also consists of some ventricular beds (Figure 4). When looking at figure 4, we have a small space of a ventricular bed present. This is because the bed comes in, pinches thicker bedding,

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

The text is formatted as a journal article and has been peer reviewed. It was published on August 31, 2015, in Europhyiscs Letters, a journal founded in 1986 by the European Physical Society. The article references multiple sources that are also academically reliable.

Neotectonic frames show comparable arrangements. Therefore, with respect to any given region the peaks of A-tents indicate comparable directions. New fault scarps have a tendency to be correlated with the territorial lineament

The land rose up and created a precipitous eastern edge of the batholith and a gentle western edge. 10 million years ago, uplift, which is the vertical rise of Earth’s surface due to natural causes, started to occur and accelerated quickly. Soon, the Sierra Nevada Mountain Range that we know today towered 14,000 feet in elevation. Throughout uplift, cracks formed in the granite of the mountains. They formed due to the pressure that came with the uplift. The erosion that stripped away most of the overlying rocks caused the remaining rock to expand and crack. These cracks are still forming today and they provide a template for future erosion.

Complete this week’s lab by filling in your responses to the questions from Geoscience Laboratory. Select answers are provided for you in red font to assist you with your lab work. Although you are only required to respond to the questions in this worksheet, you are encouraged to answer others from the text on your own.

On the first side of the outcrop the rock when examined was greenish and had small black grains indicative of diorite with hornblende giving the green color. The rock was similar to the outcrop encountered at Hollow rock which also had several fractures parallel although not as many, and that outcrop was also highly weathered. On the other side of the outcrop, the rock was incredibly different. This side was not weathered beyond recognition but

In the eastern part of the plateau most of the carbonate strata is Fredericksburg and Washita rock (Barker and Ardis 1996, 5). The plateau is dominated by a flat undistinguished plain, with the exception of the caprock mesas, the broad alluvial fans and the Balcones fault zone (Barker and Ardis 1996, 5). During the Paleozoic era the Ouachita Orogeny tectonic event occurred depositing marine sea deposits of upper Permian sediments and evaporates into the Permian basin, which is above parts of the Edwards-Trinity plateau aquifer (Anaya 2001, 107). Another prominent structural feature is the Llano uplift which is comprised of Precambrian rock mostly granite, located in the northern Hill Country area (Anaya 2001, 107). The Balcones fault zone was created from tensional stress from the uplift and deposition of sediments into the Gulf of Mexico, along the Ouachita belt, forming the faults by displacing the sediment 900 to 1200 feet (Anaya 2001, 109). The Edwards-Trinity plateau has two regional confining layers, Navarro-Del Rio, which confines the Edwards aquifer, and the Hammett that confines the Trinity and the Edward-Trinity aquifers (Barker and Ardis 1996, 2). The Navarro-Del Rio confining unit is regionally continuous within the Balcones Fault Zone; it is comprised of Buda limestone, Navarro Group,

All of the volcanic and metasedimentary rocks are metamorphosed, whose grades are extending from greenschist to upper amphibolite, characterized by low-pressure but high-temperature (Isachsen & Bowring, 1994). The influence of basement fracture zone is reflected in the homoclinal and abruptly alternated trends of the volcanic belts, which is more frequently found in the southwestern domain of the province, while north belts show angular patterns (Fyson & Helmstaedt, 1988; Padgham,1992; Padgham & Fyson, 1992). Except for the sharp dips of the volcanics, regional-scale folds, foliations and cleavages over several successions shown in the metasedimentary rocks are studied to understand the deformation and metamorphism (Isachsen & Bowring, 1994). Fyson & Helmstaedt (1988) compare three major types of folds which are ranked by their ages and sizes from oldest, most extensive F0 to minor-sized, cleavage-foliation-associated S3 folds with intermediate type F1 between them and they suggest that the parallel trend and they suggest both foliation and folds are results of syntectonic

They are called transversal when pressure builds and the rock breaks the energy of the break

These rocks grade abruptly northward into a marine geo-synclinal facies up to as much as 6,000 feet thick in the Las Vegas sub-basin. The Magdalena Group is missing from the Cimarron arch, but it most likely present in the western part of the northern Raton Basin. Orogenic debris of the Sangre de Cristo Formation of Pennsylvanian and Early Permian age was derived mainly from the San Luis uplift, filled the Rowe-Mora and Central Colorado basins, and lapped onto Precambrian rocks of the other bounding uplifts. The Sangre de Cristo Formation is 700-3,500 feet thick at the south, and 6,000-9,500 feet thick at the north (Baltz 1965).

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

There are only three structural elements within Timber Hill, with the first being the northwest-striking anticline that exhibits very low angle dips on either side of the axial plane. This anticline has a symmetrical shape and folds the Renova Formation. The more significant structural unit is the northwest-southeast striking normal fault that drops the hanging wall by approximately 600 ft. The decline of the hanging wall produced a space above the Sixmile Formation where the Quaternary Talus accumulated. The third structure is a monocline fold that formed on top of the Timber Hill Basalt. This fold formed as a result of an offset produced by the normal

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,

Scientist are struggling to come up with a widely accepted model that will explain the role of non-vertical strike-slip fault segments, crustal movement and deformation within Pacific –North American plate boundary. Multiple methods of analysis are being used; some of which are described below.