Lesson Plan: Major Landforms: Mountains and Climate
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TO BE DONE in BOOK} A
CLASS6 DATE: 16.05.2020 CHAPTER 2. LANDFORMS EXERCISE WITH QUESTION ANSWERS AND MAP WORK. 1. TICK THE RIGHT OPTION {TO BE DONE IN BOOK} a. Aravallis. b. Intermontane plateau. c. Faulting. d. Deposition. 2. FILL IN THE BLANKS {TO BE DONE IN BOOK} a. Pointed. b. Minerals. c. Fault zone. d. Old fold. 3. Differentiate between: {TO BE DONE IN NOTEBOOK} a. Old Fold Mountain Young Fold Mountain These mountains have been subjected to the They are newly formed and having forces of denudation for a long geological heights higher than old fold mountain. period. They are much lower with rounded peaks They have pointed peaks, steeper and and gentle slopes. deeper slopes. Eg: Aravalli in India. Eg: The Himalayas in India. b. Rift Valley Block mountain The lowland mass remaining after the The uplifted land mass remaining after faulting are known as Rift valley. the faulting are known as Block mountains It is bordered by fault zones and separated Block mountains are steep sided and flat by land masses. topped. Eg: Great Rift Valley of Africa. Eg: Vindhyas in India. c. Erosional Plains Depositional Plains This type of plains are formed as result of It is formed as a result of deposition of erosion and weathering. sediments. These plains have been flattened by the These plains are made by depositing the erosion of soil and rocks away from a soil and rocks on a lower surface. higher feature. Eg:- Upper Mississippi valley of USA. Eg:- The Indo-Gangetic Plains in India. d. Intermontane Plateaus Piedmont Plateaus They are the highest and the most extensive They are relatively low rolling hills with type. -
Lesson 3 Forces That Build the Land Main Idea
Lesson 3 Forces That Build the Land Main Idea Many landforms result from changes and movements in Earth’s crust. Objectives Identify types of landforms and the processes that form them. Describe what happens when an earthquake occurs. Vocabulary fault focus aftershock seismic wave epicenter seismograph magnitude vent What forces change Earth’s crust? At transform boundaries, the pieces of rock rub together in a force called shearing, like the blades of a pair of scissors, causing the rock to break. At convergent boundaries, plates collide and this force is called compression, squeezing the rock together. At divergent boundaries, plates separate causing tension, making the crust longer and thinner eventually breaking and creating a fault. Faults are usually located along the boundaries between tectonic plates. Three Kinds of Faults Shearing forms strike-slip faults. Tension forms normal faults. The rock above the fault moves down. Compression forms reverse faults. The rock above the fault moves up. Uplifted Landforms Folded mountains are mostly made up of rock layers folded by being squeezed together. Fault-block mountains are made by huge, tilted blocks of rock separated from the surrounding rock by faults. The Colorado Plateau was formed when rock layers were pushed upward. The Colorado River eventually formed the Grand Canyon. Quick Check Infer Why are faults often produced along plate boundaries? Forces act on the crust most directly at plate boundaries, because these locations are where plates are moving, relative to each other. Critical Thinking Why do some mountains form as folded mountains and others form as fault-block mountains? Compression forces form folded mountains, and tension forms fault- block mountains. -
Part 3: Normal Faults and Extensional Tectonics
12.113 Structural Geology Part 3: Normal faults and extensional tectonics Fall 2005 Contents 1 Reading assignment 1 2 Growth strata 1 3 Models of extensional faults 2 3.1 Listric faults . 2 3.2 Planar, rotating fault arrays . 2 3.3 Stratigraphic signature of normal faults and extension . 2 3.4 Core complexes . 6 4 Slides 7 1 Reading assignment Read Chapter 5. 2 Growth strata Although not particular to normal faults, relative uplift and subsidence on either side of a surface breaking fault leads to predictable patterns of erosion and sedi mentation. Sediments will fill the available space created by slip on a fault. Not only do the characteristic patterns of stratal thickening or thinning tell you about the 1 Figure 1: Model for a simple, planar fault style of faulting, but by dating the sediments, you can tell the age of the fault (since sediments were deposited during faulting) as well as the slip rates on the fault. 3 Models of extensional faults The simplest model of a normal fault is a planar fault that does not change its dip with depth. Such a fault does not accommodate much extension. (Figure 1) 3.1 Listric faults A listric fault is a fault which shallows with depth. Compared to a simple planar model, such a fault accommodates a considerably greater amount of extension for the same amount of slip. Characteristics of listric faults are that, in order to maintain geometric compatibility, beds in the hanging wall have to rotate and dip towards the fault. Commonly, listric faults involve a number of en echelon faults that sole into a lowangle master detachment. -
THE JOURNAL of GEOLOGY March 1990
VOLUME 98 NUMBER 2 THE JOURNAL OF GEOLOGY March 1990 QUANTITATIVE FILLING MODEL FOR CONTINENTAL EXTENSIONAL BASINS WITH APPLICATIONS TO EARLY MESOZOIC RIFTS OF EASTERN NORTH AMERICA' ROY W. SCHLISCHE AND PAUL E. OLSEN Department of Geological Sciences and Lamont-Doherty Geological Observatory of Columbia University, Palisades, New York 10964 ABSTRACT In many half-graben, strata progressively onlap the hanging wall block of the basins, indicating that both the basins and their depositional surface areas were growing in size through time. Based on these con- straints, we have constructed a quantitative model for the stratigraphic evolution of extensional basins with the simplifying assumptions of constant volume input of sediments and water per unit time, as well as a uniform subsidence rate and a fixed outlet level. The model predicts (1) a transition from fluvial to lacustrine deposition, (2) systematically decreasing accumulation rates in lacustrine strata, and (3) a rapid increase in lake depth after the onset of lacustrine deposition, followed by a systematic decrease. When parameterized for the early Mesozoic basins of eastern North America, the model's predictions match trends observed in late Triassic-age rocks. Significant deviations from the model's predictions occur in Early Jurassic-age strata, in which markedly higher accumulation rates and greater lake depths point to an increased extension rate that led to increased asymmetry in these half-graben. The model makes it possible to extract from the sedimentary record those events in the history of an extensional basin that are due solely to the filling of a basin growing in size through time and those that are due to changes in tectonics, climate, or sediment and water budgets. -
Mountains Block Mountains
Mountains Block Mountains • Block mountains are created when large areas or blocks of earth are broken and displaced vertically. • The uplifted blocks are termed as horsts and the lowered blocks are called graben. • Block mountains are also called fault block mountains since they are formed due to faulting as a result of tensile and compressive forces. • Block mountains are surrounded by faults on either side of rift valleys or grabens. • The Great African Rift Valley (valley floor is graben), The Rhine Valley and the Vosges mountain in Europe are examples. Compression and Tension • When the earth’s crust bends folding occurs, but when it cracks, faulting takes place. • The faulted edges are very steep, e.g. the Vosges and Black Forest of the Rhineland. • Tension may also cause the central portion to be let down between two adjacent fault blocks forming a graben or rift valley, which will have steep walls. • The East African Rift Valley system is the best example. It is 3,000 miles long, stretching from East Africa through the Red Sea to Syria. • Compressional forces set up by earth movements may produce a thrust or reverse fault and shorten the crust. A block may be raised or lowered in relation to surrounding areas. • In general large-scale block mountains and rift valleys are due to tension rather than compression. • The faults may occur in series and be further complicated by tilting and other irregularities. • Denudation through the ages modifies faulted landforms. • Block mountains may originate when the middle block moves downward and becomes a rift valley while the surrounding blocks stand higher as block mountains. -
South African Great Escarpment
Sentinel Vision EVT-227 South African Great Escarpment 19 April 2018 Sentinel-1 CSAR IW acquired on 30 August 2017 from 17:17:27 to 17:18:42 UTC Sentinel-2 MSI acquired on 03 September 2017 at 08:19:59 UTC ... Se ntinel-1 CSAR IW acquired on 08 September 2017 from 16:53:05 to 16:53:30 UTC Sentinel-3 SLSTR RBT acquired from 04 January 2018 to 07:59:47 UTC Author(s): Sentinel Vision team, VisioTerra, France - [email protected] 2D Layerstack Keyword(s): Land, mountains, geology, faults, subduction, plateau, orogeny, South Africa Fig. 1 - S2 (03.09.2017) - 11,8,2 colour composite - Zoom on Cape Town region evidencing Table Mountain. 3D view 2D view Table Mountain, Sandstone layers form the ramparts overlying a basement of Precambrian slates and granite - source: Cape Town University Department of Geological Sciences of Cape Town University describes the Geology of the Cape Peninsula: "The late-Precambrian age Malmesbury Group is the oldest rock formation in the area, consisting of alternating layers of dark grey fine-grained greywacke sandstone and slate, seen along the rocky Sea Point and Bloubergstrand shorelines. These sediments were originally deposited on an ancient continental slope by submarine slumping and turbidity currents. The sequence was subsequently metamorphosed by heat and pressure and folded tightly in a NW direction so that the rock layers are now almost vertical. The Peninsula Granite is a huge batholith that was intruded into the Malmesbury Group about 630 million years ago as molten rock (magma) and crystallized deep in the earth, but has since then been exposed by prolonged erosion. -
A Parametric Method to Model 3D Displacements Around Faults with Volumetric Vector Fields G
A parametric method to model 3D displacements around faults with volumetric vector fields G. Laurent, G. Caumon, A. Bouziat, M. Jessell To cite this version: G. Laurent, G. Caumon, A. Bouziat, M. Jessell. A parametric method to model 3D displace- ments around faults with volumetric vector fields. Tectonophysics, Elsevier, 2013, 590, pp.83-93. 10.1016/j.tecto.2013.01.015. hal-01301478 HAL Id: hal-01301478 https://hal.archives-ouvertes.fr/hal-01301478 Submitted on 23 Jul 2019 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. A parametric method to model 3D displacements around faults with volumetric vector fieldsI Gautier Laurenta,b,∗, Guillaume Caumona,b, Antoine Bouziata,b,1, Mark Jessellc, Gautier Laurenta,b,∗, Guillaume Caumona,b, Antoine Bouziata,b,1, Mark Jessellc aUniversit´ede Lorraine, CRPG UPR 2300, Vandoeuvre-l`es-Nancy,54501, France bCNRS, CRPG, UPR 2300, Vandoeuvre-l`es-Nancy, 54501, France cIRD, UR 234, GET, OMP, Universit´eToulouse III, 14 Avenue Edouard Belin, 31400 Toulouse, FRANCE Abstract This paper presents a 3D parametric fault representation for modeling the displacement field associated with faults in accordance with their geometry. The displacements are modeled in a canonical fault space where the near-field displacement is defined by a small set of parameters consisting of the maximum displacement amplitude and the profiles of attenuation in the surrounding space. -
Garlock Fault: an Intracontinental Transform Structure, Southern California
GREGORY A. DAVIS Department of Geological Sciences, University of Southern California, Los Angeles, California 90007 B. C. BURCHFIEL Department of Geology, Rice University, Houston, Texas 77001 Garlock Fault: An Intracontinental Transform Structure, Southern California ABSTRACT Sierra Nevada. Westward shifting of the north- ern block of the Garlock has probably contrib- The northeast- to east-striking Garlock fault uted to the westward bending or deflection of of southern California is a major strike-slip the San Andreas fault where the two faults fault with a left-lateral displacement of at least meet. 48 to 64 km. It is also an important physio- Many earlier workers have considered that graphic boundary since it separates along its the left-lateral Garlock fault is conjugate to length the Tehachapi-Sierra Nevada and Basin the right-lateral San Andreas fault in a regional and Range provinces of pronounced topogra- strain pattern of north-south shortening and phy to the north from the Mojave Desert east-west extension, the latter expressed in part block of more subdued topography to the as an eastward displacement of the Mojave south. Previous authors have considered the block away from the junction of the San 260-km-long fault to be terminated at its Andreas and Garlock faults. In contrast, we western and eastern ends by the northwest- regard the origin of the Garlock fault as being striking San Andreas and Death Valley fault directly related to the extensional origin of the zones, respectively. Basin and Range province in areas north of the We interpret the Garlock fault as an intra- Garlock. -
Spatial Characteristics and Controlling Factors of the Strike-Slip Fault Zones in the Northern Slope of Tazhong Uplift, Tarim Ba
Spatial Characteristics and Controlling Factors of the Strike-slip Fault Zones in the Northern Slope of Tazhong Uplift, Tarim Basin: Insight from 3D Seismic Data Xiaoying Han 1, 2, 3, Liangjie Tang 1, 2 *, Shang Deng 4, Zicheng Cao 5 1. State Key Laboratory of Petroleum Resource and Prospecting, China University of Petroleum, Beijing 102249, China 2. Basin & Reservoir Research Center, China University of Petroleum, Beijing 102249, China 3. College of Mining Engineering, North China University of Science and Technology, Tangshan, 063009, China 4. Petroleum Exploration and Production Research Institute, SINOPEC, Beijing 100083, China 5. Exploration and Production Research Institute of Northwest Oilfield Branch Company, SINOPEC, Urumqi 830000, China *Corresponding author: Liangjie Tang E-mail address: [email protected] Telephone: +86 13701288636 Postal address: No18 Fuxue Road, Changping District, Beijing China University of Petroleum-Beijing, Beijing 102249, China Abstract: The detailed characteristics of the Paleozoic strike-slip fault zones developed in the northern slope of Tazhong uplift are closely related to hydrocarbon explorations. In this study, five major strike-slip fault zones that cut through the Cambrian-Middle Devonian units are identified, by using 3D seismic data. Each of the strike-slip fault zones is characterized by two styles of deformation, namely deeper strike-slip faults and shallower en-echelon faults. By counting the reverse separation of the horizon along the deeper faults, activity intensity on the deeper strike-slip faults in the south is stronger than that on the northern ones. The angle between the strike of the shallower en-echelon normal faults and the principal displacement zone (PDZ) below them is likely to have a tendency to decrease slightly from the south to the north, which may indicate that activity intensity on the shallower southern en-echelon faults is stronger than that on the northern ones. -
The Role of Subducting Plate Rheology in Outer-Rise Seismicity: Implications for Japan and South American Subduction Systems
Syracuse University SURFACE Syracuse University Honors Program Capstone Syracuse University Honors Program Capstone Projects Projects Spring 5-1-2015 The role of subducting plate rheology in outer-rise seismicity: Implications for Japan and South American subduction systems Karolina Lubecka Follow this and additional works at: https://surface.syr.edu/honors_capstone Part of the Geology Commons, Geophysics and Seismology Commons, and the Tectonics and Structure Commons Recommended Citation Lubecka, Karolina, "The role of subducting plate rheology in outer-rise seismicity: Implications for Japan and South American subduction systems" (2015). Syracuse University Honors Program Capstone Projects. 830. https://surface.syr.edu/honors_capstone/830 This Honors Capstone Project is brought to you for free and open access by the Syracuse University Honors Program Capstone Projects at SURFACE. It has been accepted for inclusion in Syracuse University Honors Program Capstone Projects by an authorized administrator of SURFACE. For more information, please contact [email protected]. The role of subducting plate rheology in outer-rise seismicity: Implications for Japan and South American subduction systems A Capstone Project Submitted in Partial Fulfillment of the Requirements of the Renée Crown University Honors Program at Syracuse University Karolina Lubecka Candidate for B.S. Degree and Renée Crown University Honors May 2015 Honors Capstone Project in Earth Science Capstone Project Advisor: _______________________ Dr. Robert Moucha Capstone Project Reader: _______________________ Dr. Gregory Hoke Honors Director: _______________________ Stephen Kuusisto, Director Date: May 5, 2015 i Abstract The outer rise is a subtle ridge on the seafloor located near an oceanic trench where a down-going lithospheric plate begins to bend and thus fault prior to subducting at the subduction zone. -
The Late Bajocian-Bathonian Evolution of the Oseberg-Brage Area, Northern North Sea
Sedimentation history as an indicator of rift initiation and development: the Late Bajocian-Bathonian evolution of the Oseberg-Brage area, northern North Sea RODMAR RAVNÅS, KAREN BONDEVIK, WILLIAM HELLAND-HANSEN, LEIF LØMO, ALF RYSETH & RON J. STEEL Ravnås, R., Bondevik, K., Helland-Hansen, W., Lømo, L., Ryseth, A. & Steel, R. J.: Sedimentation history as an indicator of rift initiation and development: the Late Bajocian-Bathonian evolution of the Oseberg-Brage area, northem North Sea. Norsk Geologisk Tidsskrift, Vol. 77, pp. 205-232. Oslo 1997. ISSN 0029 -196X. The Tarbert Formation in the Oseberg-Brage area consists of shoreline sandstones and lower delta-plain heterolithics which basinward interdigitate with offshore sediments of the lower Heather Formation and landward with fluvio-deltaic deposits of the upper Ness Formation. The Late Bajocian-Tarbert and lower Heather Formations form three wedge-shaped, regressive-transgressive sequences which constitute offset, landward-stepping shoreline prisms. Initial gentle rotational extensional faulting occurred during the deposition of the uppermost Ness Formation and resulted in basinfloor subsidence and flooding across the Brent delta. Subsequent extensional faulting exerted the major control on the drainage development, basin physiography, the large-scale stacking pattem, i.e. the progradational-to-backstepping nature of the sequences, as well as on the contained facies tracts and higher-order stacking pattem in the regressive and transgressive segments. Progradation occurred during repetitive tectonic dormant stages, whereas the successive transgressive segments are coupled against intervening periods with higher rates of rotational faulting and overall basinal subsidence. Axial drainage dominated during the successive tectonic dormant stages. Transverse drainage increased in influence during the intermittent rotational tilt stages, but only as small, local (fault block) hanging-wall and footwall sedimentary lobes. -
4. Deep-Tow Observations at the East Pacific Rise, 8°45N, and Some Interpretations
4. DEEP-TOW OBSERVATIONS AT THE EAST PACIFIC RISE, 8°45N, AND SOME INTERPRETATIONS Peter Lonsdale and F. N. Spiess, University of California, San Diego, Marine Physical Laboratory, Scripps Institution of Oceanography, La Jolla, California ABSTRACT A near-bottom survey of a 24-km length of the East Pacific Rise (EPR) crest near the Leg 54 drill sites has established that the axial ridge is a 12- to 15-km-wide lava plateau, bounded by steep 300-meter-high slopes that in places are large outward-facing fault scarps. The plateau is bisected asymmetrically by a 1- to 2-km-wide crestal rift zone, with summit grabens, pillow walls, and axial peaks, which is the locus of dike injection and fissure eruption. About 900 sets of bottom photos of this rift zone and adjacent parts of the plateau show that the upper oceanic crust is composed of several dif- ferent types of pillow and sheet lava. Sheet lava is more abundant at this rise crest than on slow-spreading ridges or on some other fast- spreading rises. Beyond 2 km from the axis, most of the plateau has a patchy veneer of sediment, and its surface is increasingly broken by extensional faults and fissures. At the plateau's margins, secondary volcanism builds subcircular peaks and partly buries the fault scarps formed on the plateau and at its boundaries. Another deep-tow survey of a patch of young abyssal hills 20 to 30 km east of the spreading axis mapped a highly lineated terrain of inactive horsts and grabens. They were created by extension on inward- and outward- facing normal faults, in a zone 12 to 20 km from the axis.