Uplift of Earth's Crust
Total Page:16
File Type:pdf, Size:1020Kb
Load more
Recommended publications
-
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. -
Bare Bedrock Erosion Rates in the Central Appalachians, Virginia
W&M ScholarWorks Undergraduate Honors Theses Theses, Dissertations, & Master Projects 5-2009 Bare Bedrock Erosion Rates in the Central Appalachians, Virginia Jennifer Whitten College of William and Mary Follow this and additional works at: https://scholarworks.wm.edu/honorstheses Part of the Geology Commons Recommended Citation Whitten, Jennifer, "Bare Bedrock Erosion Rates in the Central Appalachians, Virginia" (2009). Undergraduate Honors Theses. Paper 326. https://scholarworks.wm.edu/honorstheses/326 This Honors Thesis is brought to you for free and open access by the Theses, Dissertations, & Master Projects at W&M ScholarWorks. It has been accepted for inclusion in Undergraduate Honors Theses by an authorized administrator of W&M ScholarWorks. For more information, please contact [email protected]. BARE BEDROCK EROSION RATES IN THE CENTRAL APPALACHIANS, VIRGINIA A thesis submitted in partial fulfillment of the requirement for the degree of Bachelors of Science in Geology from The College of William and Mary by Jennifer Whitten Accepted for ___________________________________ (Honors, High Honors, Highest Honors) ________________________________________ Gregory Hancock, Director ________________________________________ Christopher Bailey ________________________________________ James Kaste ________________________________________ Scott Southworth Williamsburg, VA April 30, 2009 Table of Contents Abstract......................................................................................................................................................3 -
Ocean Basin Bathymetry & Plate Tectonics
13 September 2018 MAR 110 HW- 3: - OP & PT 1 Homework #3 Ocean Basin Bathymetry & Plate Tectonics 3-1. THE OCEAN BASIN The world’s oceans cover 72% of the Earth’s surface. The bathymetry (depth distribution) of the interconnected ocean basins has been sculpted by the process known as plate tectonics. For example, the bathymetric profile (or cross-section) of the North Atlantic Ocean basin in Figure 3- 1 has many features of a typical ocean basins which is bordered by a continental margin at the ocean’s edge. Starting at the coast, there is a slight deepening of the sea floor as we cross the continental shelf. At the shelf break, the sea floor plunges more steeply down the continental slope; which transitions into the less steep continental rise; which itself transitions into the relatively flat abyssal plain. The continental shelf is the seaward edge of the continent - extending from the beach to the shelf break, with typical depths ranging from 130 m to 200 m. The seafloor of the continental shelf is gently sloping with undulating surfaces - sometimes interrupted by hills and valleys (see Figure 3- 2). Sediments - derived from the weathering of the continental mountain rocks - are delivered by rivers to the continental shelf and beyond. Over wide continental shelves, the sea floor slopes are 1° to 2°, which is virtually flat. Over narrower continental shelves, the sea floor slopes are somewhat steeper. The continental slope connects the continental shelf to the deep ocean with typical depths of 2 to 3 km. While the bottom slope of a typical continental slope region appears steep in the 13 September 2018 MAR 110 HW- 3: - OP & PT 2 vertically-exaggerated valleys pictured (see Figure 3-2), they are typically quite gentle with modest angles of only 4° to 6°. -
Sedimentological Constraints on the Initial Uplift of the West Bogda Mountains in Mid-Permian
www.nature.com/scientificreports OPEN Sedimentological constraints on the initial uplift of the West Bogda Mountains in Mid-Permian Received: 14 August 2017 Jian Wang1,2, Ying-chang Cao1,2, Xin-tong Wang1, Ke-yu Liu1,3, Zhu-kun Wang1 & Qi-song Xu1 Accepted: 9 January 2018 The Late Paleozoic is considered to be an important stage in the evolution of the Central Asian Orogenic Published: xx xx xxxx Belt (CAOB). The Bogda Mountains, a northeastern branch of the Tianshan Mountains, record the complete Paleozoic history of the Tianshan orogenic belt. The tectonic and sedimentary evolution of the west Bogda area and the timing of initial uplift of the West Bogda Mountains were investigated based on detailed sedimentological study of outcrops, including lithology, sedimentary structures, rock and isotopic compositions and paleocurrent directions. At the end of the Early Permian, the West Bogda Trough was closed and an island arc was formed. The sedimentary and subsidence center of the Middle Permian inherited that of the Early Permian. The west Bogda area became an inherited catchment area, and developed a widespread shallow, deep and then shallow lacustrine succession during the Mid- Permian. At the end of the Mid-Permian, strong intracontinental collision caused the initial uplift of the West Bogda Mountains. Sedimentological evidence further confrmed that the West Bogda Mountains was a rift basin in the Carboniferous-Early Permian, and subsequently entered the Late Paleozoic large- scale intracontinental orogeny in the region. The Central Asia Orogenic Belt (CAOB) is the largest accretionary orogen on Earth, which was formed by the amalgamation of multiple micro-continents, island arcs and accretionary wedges1–5. -
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. -
Appalachian County
APPALACHIANARC-DESIGNATED REGION DEVELOPMENT DISTRESSED COUNTIES County EconomicHIGHWAYFiscal Year SYSTEM Status2020 in Appalachia, Fiscal Year 2008 (ESeptemberective October 30, 2015 1, 2007 through September 30, 2008) APPALACHIAN REGION NEW YORK WISCONSIN NNEWEW YYORKORK ALBANY MICHIGAN OTSEGO CHENANGO 6-C SCHOHARIE WWISCONSINISCISCONSIONSINN MICHIGAN CORTLAND W SCHUYLER TOMPKINS 6-B ELMIRA T DELAWARE STEUBEN 6-A CHEMUNG TIOGA BROOMEBINGHAMTON M ICHIGAN JAMESTOWNALLEGANY M ICHIGAN CATTARAUGUST CHAUTAUQUA CHICAGO ERIE U-1 SUSQUEHANNA T U-1 UBRADFORD WAYNE ERIE WARREN MC KEAN KEAN TIOGA U POTTER 9-C LACKAWANNA 9-D CRAWFORD WYOMING ASHTABULA CAMERON P ENNSYLFORESTPENNSYLVANIACAMERON V ANIASCRANTON PFORESTENNSYLVANIASULLIVAN PIKE TOLEDO CLEVELAND8-D 9-A ELK VENANGO LYCOMING 9-B CLINTON LUZERNE MERCER WILLIAMSPORT TRUMBULL CLARION COLUMBIA MONROE 9-G MON- CARBON P ENNSYLVANIAP TOUR AKRON CLEARFIELD P ENNSYLVANIAJEFFERSON PUNION CENTRE MAHONING SCHUYLKILL P-1 SCHUYLKILL BUTLER ARMSTRONG O-1 STATE COLLEGESNYDER NORTH-NORTH- LAWRENCE O-1 STATE COLLEGEUMBERLAND UMBERLAND COLUMBIANA O BEAVER ALTOONA 9-E O MIFFLIN INDIANA CARROLL M M BLAIR JUNIATAM HARRISBURG M PERRY HOLMES CAMBRIA NJ ALLEGHENY HANCOCK HANCOCK JOHNSTOWN MM HUNTINGDON PITTSBURGHPITTSBURGH13-K WESTMORELAND A LLINOIS NDIANA HIO COSHOCTON VANI I TUSCARAWAS I O JEFFERSON HARRISON BROOKE I LLINOIS I NDIANA O HIO BROOKE 9-F O PENNSYL EW ILLINOIS INDIANA OHIOOHIO WASHINGTON COLUMBUS 8-C OHIO BEDFORD INDIANA GUERNSEY SOMERSET INDIANAPOLIS BELMONT FULTON ILLINOIS WHEELING GREENE FAYETTE -
Historical Significance of American Chestnut to Appalachian Culture and Ecology
Davis, D.E. 2005. Historical significance of American chestnut to Appalachian culture and ecology. In, proc. of conf. on restoration of American chestnut to forest lands, Steiner, K.C. and J.E. Carlson (eds.). HISTORICAL SIGNIFICANCE OF AMERICAN CHESTNUT TO APPALACHIAN CULTURE AND ECOLOGY Donald E. Davis Social Sciences Division, Dalton State College, Dalton, GA 30720 USA ([email protected]) Abstract: This paper explores the significance of the American chestnut on the ecology and culture of Appalachia. Until the third decade of the 20th century, the tree was the crowning glory of the Appalachian hardwood forest, in some isolated areas comprising half of the hardwood tree population. The wildlife of the region, particularly black bears, heavily depended on the tree for both sustenance and shelter. Native Americans in the mountains frequently made use of the nut, mixing chestnut meal with corn to make bread. White mountaineers gathered the nuts to sell or trade, and sometimes used parched chestnuts as a coffee substitute. The American chestnut played a major role in the economy of the Appalachian region, providing timber for dwellings and tannic acid for the leather industry. Finally, it is argued that the decline of Appalachian subsistence culture is directly linked to the loss of the American chestnut. INTRODUCTION Few single events in North American environmental history compare with the loss of the American chestnut. “The devastation of the American chestnut by the chestnut blight," wrote William MacDonald more than two decades ago, "represents one of the greatest recorded changes in natural plant population caused by an introduced organism." MacDonald, a professor of plant pathology at West Virginia University and the current acting treasurer of the American Chestnut Foundation, estimates that chestnut-dominated forests once covered 200 million acres of land from Maine to Mississippi (MacDonald 1978; Brown and Davis 1995). -
Asthenosphere–Lithospheric Mantle Interaction in an Extensional Regime
Chemical Geology 233 (2006) 309–327 www.elsevier.com/locate/chemgeo Asthenosphere–lithospheric mantle interaction in an extensional regime: Implication from the geochemistry of Cenozoic basalts from Taihang Mountains, North China Craton ⁎ Yan-Jie Tang , Hong-Fu Zhang, Ji-Feng Ying State Key Laboratory of Lithospheric Evolution, Institute of Geology and Geophysics, Chinese Academy of Sciences, P.O. Box 9825, Beijing 100029, PR China Received 25 July 2005; received in revised form 27 March 2006; accepted 30 March 2006 Abstract Compositions of Cenozoic basalts from the Fansi (26.3–24.3 Ma), Xiyang–Pingding (7.9–7.3 Ma) and Zuoquan (∼5.6 Ma) volcanic fields in the Taihang Mountains provide insight into the nature of their mantle sources and evidence for asthenosphere– lithospheric mantle interaction beneath the North China Craton. These basalts are mainly alkaline (SiO2 =44–50 wt.%, Na2O+ K2O=3.9–6.0 wt.%) and have OIB-like characteristics, as shown in trace element distribution patterns, incompatible elemental (Ba/Nb=6–22, La/Nb=0.5–1.0, Ce/Pb=15–30, Nb/U=29–50) and isotopic ratios (87Sr/86Sr=0.7038–0.7054, 143Nd/ 144 Nd=0.5124–0.5129). Based on TiO2 contents, the Fansi lavas can be classified into two groups: high-Ti and low-Ti. The Fansi high-Ti and Xiyang–Pingding basalts were dominantly derived from an asthenospheric source, while the Zuoquan and Fansi low-Ti basalts show isotopic imprints (higher 87Sr/86Sr and lower 143Nd/144Nd ratios) compatible with some contributions of sub- continental lithospheric mantle. The variation in geochemical compositions of these basalts resulted from the low degree partial melting of asthenosphere and the interaction of asthenosphere-derived magma with old heterogeneous lithospheric mantle in an extensional regime, possibly related to the far effect of the India–Eurasia collision. -
A Geomorphic Classification System
A Geomorphic Classification System U.S.D.A. Forest Service Geomorphology Working Group Haskins, Donald M.1, Correll, Cynthia S.2, Foster, Richard A.3, Chatoian, John M.4, Fincher, James M.5, Strenger, Steven 6, Keys, James E. Jr.7, Maxwell, James R.8 and King, Thomas 9 February 1998 Version 1.4 1 Forest Geologist, Shasta-Trinity National Forests, Pacific Southwest Region, Redding, CA; 2 Soil Scientist, Range Staff, Washington Office, Prineville, OR; 3 Area Soil Scientist, Chatham Area, Tongass National Forest, Alaska Region, Sitka, AK; 4 Regional Geologist, Pacific Southwest Region, San Francisco, CA; 5 Integrated Resource Inventory Program Manager, Alaska Region, Juneau, AK; 6 Supervisory Soil Scientist, Southwest Region, Albuquerque, NM; 7 Interagency Liaison for Washington Office ECOMAP Group, Southern Region, Atlanta, GA; 8 Water Program Leader, Rocky Mountain Region, Golden, CO; and 9 Geology Program Manager, Washington Office, Washington, DC. A Geomorphic Classification System 1 Table of Contents Abstract .......................................................................................................................................... 5 I. INTRODUCTION................................................................................................................. 6 History of Classification Efforts in the Forest Service ............................................................... 6 History of Development .............................................................................................................. 7 Goals