Crustal Uplift and Subsidence Due to the Interaction Between Tectonic and Surface Processes – an Integrated 3D Numerical Approach for Spatial Quantification
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The Rock Cycle Compressed and Cemented to Form What the Original Rocks on Earth Were Like
| The Rock Cycle compressed and cemented to form what the original rocks on Earth were like. sedimentary rock, such as sandstone. IMMG has some excellent examples of Soluble material can be precipitated from these extraterrestrial visitors in our The continual set of processes affecting water to form sedimentary rocks such as meteorite exhibit. rocks is called the rock cycle. All existing limestone and gypsum. Sedimentary rocks rocks on Earth have been changed over can also be exposed at the surface and Various examples of the three different time by various geologic processes. Earth undergo erosion, providing materials for types of rocks are listed below. Specimens was formed about 4.6 billion years ago, and future sedimentary rocks. of some of these rocks can be found the oldest known rock unit is found in throughout the museum. Canada, dated at just over 4 billion years If sedimentary rocks become buried deep old. This rock material was altered by heat within the crust, they can be subjected to How many can you find? and pressure into the metamorphic rock high heat and pressure along with physical gneiss. stresses such as compression or extension, Igneous which transforms them into metamorphic rocks such as schist or gneiss Originally all of Earth’s crustal rocks had Basalt Gabbro Diorite an igneous origin. They start as semi- (“metamorphic” simply means “changed molten magma in the upper mantle and form”). Sometimes igneous rocks can be Rhyolite Syenite Andesite either rise to the surface as extrusive lava metamorphosed by similar processes (like Granite Granodiorite Obsidian (like basalt) in volcanoes and oceanic rifts, granite into gneiss). -
Short-Lived Increase in Erosion During the African Humid Period: Evidence from the Northern Kenya Rift ∗ Yannick Garcin A, , Taylor F
Earth and Planetary Science Letters 459 (2017) 58–69 Contents lists available at ScienceDirect Earth and Planetary Science Letters www.elsevier.com/locate/epsl Short-lived increase in erosion during the African Humid Period: Evidence from the northern Kenya Rift ∗ Yannick Garcin a, , Taylor F. Schildgen a,b, Verónica Torres Acosta a, Daniel Melnick a,c, Julien Guillemoteau a, Jane Willenbring b,d, Manfred R. Strecker a a Institut für Erd- und Umweltwissenschaften, Universität Potsdam, Germany b Helmholtz-Zentrum Potsdam, Deutsches GeoForschungsZentrum GFZ, Telegrafenberg Potsdam, Germany c Instituto de Ciencias de la Tierra, Universidad Austral de Chile, Casilla 567, Valdivia, Chile d Scripps Institution of Oceanography – Earth Division, University of California, San Diego, La Jolla, USA a r t i c l e i n f o a b s t r a c t Article history: The African Humid Period (AHP) between ∼15 and 5.5 cal. kyr BP caused major environmental change Received 2 June 2016 in East Africa, including filling of the Suguta Valley in the northern Kenya Rift with an extensive Received in revised form 4 November 2016 (∼2150 km2), deep (∼300 m) lake. Interfingering fluvio-lacustrine deposits of the Baragoi paleo-delta Accepted 8 November 2016 provide insights into the lake-level history and how erosion rates changed during this time, as revealed Available online 30 November 2016 by delta-volume estimates and the concentration of cosmogenic 10Be in fluvial sand. Erosion rates derived Editor: A. Yin −1 10 from delta-volume estimates range from 0.019 to 0.03 mm yr . Be-derived paleo-erosion rates at −1 Keywords: ∼11.8 cal. -
Deformation Characteristics of the Shear Zone and Movement of Block Stones in Soil–Rock Mixtures Based on Large-Sized Shear Test
applied sciences Article Deformation Characteristics of the Shear Zone and Movement of Block Stones in Soil–Rock Mixtures Based on Large-Sized Shear Test Zhiqing Li 1,2,3,*, Feng Hu 1,2,3, Shengwen Qi 1,2,3, Ruilin Hu 1,2,3, Yingxin Zhou 4 and Yawei Bai 5 1 Key Laboratory of Shale Gas and Geoengineering, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China; [email protected] (F.H.); [email protected] (S.Q.); [email protected] (R.H.) 2 College of Earth and Planetary Science, University of Chinese Academy of Sciences, Beijing 100049, China 3 Innovation Academy of Earth Science, Chinese Academy of Sciences, Beijing 100029, China 4 Yunnan Chuyao Expressway Construction Headquarters, Chuxiong 675000, China; [email protected] 5 Henan Yaoluanxi Expressway Construction Co. LTD, Luanchuan 471521, China; [email protected] * Correspondence: [email protected] or [email protected]; Tel.: +86-13671264387 Received: 27 July 2020; Accepted: 15 September 2020; Published: 17 September 2020 Abstract: Soil–rock mixtures (SRM) have the characteristics of distinct heterogeneity and an obvious structural effect, which make their physical and mechanical properties very complex. This study aimed to investigate the deformation properties and failure mode of the shear zone as well as the movement of block stones in SRM experimentally, not only considering SRM shear strength. The particle composition and proportion of specimens were based on field samples from an SRM slope along national highway 318 in Xigaze, Tibet. Shear zone deformation tests were carried out using an SRM-1000 large-sized geotechnical apparatus controlled by a motor servo, considering the effects of different stone contents by mass (0, 30%, 50%, 70%), vertical pressures (50, 100, 200, 300, and 400 kPa), and block stone sizes (9.5–19.0, 19.0–31.5, and 31.5–53.0 mm). -
Weathering, Erosion, and Susceptibility to Weathering Henri Robert George Kenneth Hack
Weathering, erosion, and susceptibility to weathering Henri Robert George Kenneth Hack To cite this version: Henri Robert George Kenneth Hack. Weathering, erosion, and susceptibility to weathering. Kanji, Milton; He, Manchao; Ribeira e Sousa, Luis. Soft Rock Mechanics and Engineering, Springer Inter- national Publishing, pp.291-333, 2020, 9783030294779. 10.1007/978-3-030-29477-9. hal-03096505 HAL Id: hal-03096505 https://hal.archives-ouvertes.fr/hal-03096505 Submitted on 5 Jan 2021 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. Published in: Hack, H.R.G.K., 2020. Weathering, erosion and susceptibility to weathering. 1 In: Kanji, M., He, M., Ribeira E Sousa, L. (Eds), Soft Rock Mechanics and Engineering, 1 ed, Ch. 11. Springer Nature Switzerland AG, Cham, Switzerland. ISBN: 9783030294779. DOI: 10.1007/978303029477-9_11. pp. 291-333. Weathering, erosion, and susceptibility to weathering H. Robert G.K. Hack Engineering Geology, ESA, Faculty of Geo-Information Science and Earth Observation (ITC), University of Twente Enschede, The Netherlands e-mail: [email protected] phone: +31624505442 Abstract: Soft grounds are often the result of weathering. Weathering is the chemical and physical change in time of ground under influence of atmosphere, hydrosphere, cryosphere, biosphere, and nuclear radiation (temperature, rain, circulating groundwater, vegetation, etc.). -
Correlating Foreland Basin Subsidence with Eclogite Metamorphism
ATI..ANTic GEOLOGY 79 Loading the Laurentian margin: correlating foreland basin subsidence with eclogite metamorphism 2 3 4 John WF. Waldron•, R.A. Jamieson , G.S. Stockmal and L.A. Quinn 1Geology Department, Saint Mary '.S' University, Halifax, Nova Scotia B3H 3C3, Canada 'Department ofEarth Sciences, Dalhousie University, Halifax, Nova Scotia B3H 3J5, Canada 1Geological Survey of Canada (Calgary), 3303-33rd Street Northwest, Calgary, Alberta T2L 2A 7, Canada 'Department ofGeology, Brandon University, Brandon, Manitoba R7A 6A9, Canada Paleozoic loading of the former Laurentian continental de Lys Supergroup) are exposed in the Baie Verte Peninsula margin is recorded both in the subsidence history of the Ap and elsewhere. These units record Barrovian metamorphism palachian foreland basin and in metamorphic rocks now ex with peak temperatures around 700 to 750°C at 7 to 9 kbar; humed in internal parts of the Newfoundland Humber zone. isotopic data indicate that peak temperatures were reached in The Cambrian-Ordovician passive margin ofLaurentia Early Silurian time ('Salinian orogeny'), followed by rapid ex underwent a transition to a foreland basin setting beginning humation. Amphibolite facies metamorphism overprints an in Early Ordovician time. Middle Ordovician ('Taconian ') foreland earlier eclogite facies assemblage, for which minimum pres basin sediments (Table Head and Goose Tickle groups), in sures of 1.2 GPa at 500°C require burial of the Laurentian part derived from the Humber Arm Allochthon, are relatively margin beneath at least 40 km of overburden, which may have thin (ca. 250 m in offshore industry seismic data, thinning to included thrust sheets of continental margin rocks and the west). -
Exhumation Processes
Exhumation processes UWE RING1, MARK T. BRANDON2, SEAN D. WILLETT3 & GORDON S. LISTER4 1Institut fur Geowissenschaften,Johannes Gutenberg-Universitiit,55099 Mainz, Germany 2Department of Geology and Geophysics, Yale University, New Haven, CT 06520, USA 3Department of Geosciences, Pennsylvania State University, University Park, PA I 6802, USA Present address: Department of Geological Sciences, University of Washington, Seattle, WA 98125, USA 4Department of Earth Sciences, Monash University, Clayton, Victoria VIC 3168,Australia Abstract: Deep-seated metamorphic rocks are commonly found in the interior of many divergent and convergent orogens. Plate tectonics can account for high-pressure meta morphism by subduction and crustal thickening, but the return of these metamorphosed crustal rocks back to the surface is a more complicated problem. In particular, we seek to know how various processes, such as normal faulting, ductile thinning, and erosion, con tribute to the exhumation of metamorphic rocks, and what evidence can be used to distin guish between these different exhumation processes. In this paper, we provide a selective overview of the issues associated with the exhuma tion problem. We start with a discussion of the terms exhumation, denudation and erosion, and follow with a summary of relevant tectonic parameters. Then, we review the charac teristics of exhumation in differenttectonic settings. For instance, continental rifts, such as the severely extended Basin-and-Range province, appear to exhume only middle and upper crustal rocks, whereas continental collision zones expose rocks from 125 km and greater. Mantle rocks are locally exhumed in oceanic rifts and transform zones, probably due to the relatively thin crust associated with oceanic lithosphere. -
Metamorphism Associated with Extensional Rifting of Gondwana
Geological Society, London, Special Publications Basement and cover rock history in western Tethys: HT-LP metamorphism associated with extensional rifting of Gondwana Robert Hall Geological Society, London, Special Publications 1988; v. 37; p. 41-50 doi:10.1144/GSL.SP.1988.037.01.04 Email alerting click here to receive free email alerts when new articles cite this article service Permission click here to seek permission to re-use all or part of this article request Subscribe click here to subscribe to Geological Society, London, Special Publications or the Lyell Collection Notes Downloaded by Robert Hall on 26 November 2007 © 1988 Geological Society of London Basement and cover rock history in western Tethys: HT-LP metamorphism associated with extensional rifting of Gondwana Robert Hall ABSTRACT: High-temperature-low-pressure metamorphism of the deep crust is probable during continental lithospheric extension. The 75-65 Ma cooling ages of metamorphic and magmatic rocks preserved in overthrust crystalline slices in the southern Aegean are most plausibly explained by late Cretaceous extension of the Apulian continental margin, rather than by subduction-related magmatism. Metamorphism and magmatism at depth can be correlated with those stratigraphic features of the cover sequences that indicate extension. In particular, the puzzling 'premier flysch' of the region is interpreted as one consequence of peripheral uplift associated with stretching. Introduction observed in overthrust terrains, but evidence of the extensional history of the margin may also be discernible from interpretation of the sedimen- Many recent models for the evolution of passive tary sequences deposited within the former con- continental margins imply the possibility of a tinental margin. -
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. -
Geophysical Abstracts 156-159 January-December 1954
Geophysical Abstracts 156-159 January-December 1954 GEOLOGICAL SURVEY BULLETIN 1022 Abstracts of current literature pertaining to the physics of the solid earth and geophysicq,l exploration UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1955 UNITED STATESlDEPARTMENT OF THE INTERIOR Douglas McKay, Secretary GEOLOGICAL SURVEY W. ~· Wrather, Director CONTENTS [The letters in parentheses are those used to designate the chapters for separate publication] Page (A) Geophysical Abstracts 156, January-March------------------------ 1 (B) Geophysical Abstracts 157, April-June---------------------------- 71 (C) Geophysical Abstracts 158, July-September________________________ 135 (D) Geophysical Abstracts 159, October-December_____________________ 205 Under department orders, Geophysical Abstracts have been published at different times by the Bureau of Mines or the Geological Survey as noted below: 1-86, May 1929-June· 1936, Bureau of Mines Information Circulars. [Mimeo- graphed] 87, July-December 1936, Geological Survey Bulletin 887. 88-91, January-December 1937, Geological Survey Bulletin 895. 92-95, January-December 1938, Geological Survey Bulletin 909. 96-99, January-December 1939, Geological Survey Bulletin 915. 100-103, January-December 1940, Geological Survey Bulletin 925. 104-107, January-December 1941, Geological Survey Bulletin 932. 108-111, January-December 1942, Geological Survey Bulletin 939. 112-127, January 1943-December 1946, Bureau of Mines Information Circulars. [Mimeographed] 128-131, January-December 1947, Geological Survey Bulletin 957. 132-135, January-December 1948, Geological Survey Bulletin 959. 136-139, January-December 1949, Geological Survey Bulletin 966. 140-143, January-December 1950, Geological Survey Bulletin 976. 144-147, January-December 1951, Geological Survey Bulletin 981. 148-151, January-December 1952, Geological Survey Bulletin 991. 152-155, January-December 1953, Geological Survey Bulletin 1002. -
A Nonlinear Response of Sahel Rainfall to Atlantic Warming
7080 JOURNAL OF CLIMATE VOLUME 26 A Nonlinear Response of Sahel Rainfall to Atlantic Warming NARESH NEUPANE AND KERRY H. COOK Department of Geological Sciences, Jackson School of Geosciences, The University of Texas at Austin, Austin, Texas (Manuscript received 24 July 2012, in final form 2 February 2013) ABSTRACT The response over West Africa to uniform warming of the Atlantic Ocean is analyzed using idealized simulations with a regional climate model. With warming of 1 and 1.5 K, rainfall rates increase by 30%–50% over most of West Africa. With Atlantic warming of 2 K and higher, coastal precipitation increases but Sahel rainfall decreases substantially. This nonlinear response in Sahel rainfall is the focus of this analysis. Atlantic warming is accompanied by decreases in low-level geopotential heights in the Gulf of Guinea and in the large- scale meridional geopotential height gradient. This leads to easterly wind anomalies in the central Sahel. With Atlantic warming below 2 K, these easterly anomalies support moisture transport from the Gulf of Guinea and precipitation increases. With Atlantic warming over 2 K, the easterly anomalies reverse the westerly flow over the Sahel. The resulting dry air advection into the Sahel reduces precipitation. Increased low-level moisture provides moist static energy to initiate convection with Atlantic warming at 1.5 K and below, while decreased moisture and stable thermal profiles suppress convection with additional warming. In all simula- tions, the southerly monsoon flow onto the Guinean coast is maintained and precipitation in that region increases. The relevance of these results to the global warming problem is limited by the focus on Atlantic warming alone. -
6. Relative and Absolute Dating
6. Relative and Absolute Dating Adapted by Sean W. Lacey & Joyce M. McBeth (2018) University of Saskatchewan from Deline B, Harris R, & Tefend K. (2015) "Laboratory Manual for Introductory Geology". First Edition. Chapter 1 "Relative and Absolute Dating" by Bradley Deline, CC BY-SA 4.0. View Source. 6.1 INTRODUCTION To develop a history of how geologic events have acted on the Earth through time, we need to understand what and when geological processes have occurred through Earth's history. Geologists learn about what processes occur on Earth through studying the rock record and observing geologic processes in modern environments. To understand when these processes have acted during Earth's geologic time, geologists make observations about the relationships of rocks to one another in the rock record, using a process called relative dating. Geologists use this information to construct models for how these relationships developed. For example, if the rock record in an area contains sedimentary rocks that are folded, a model to explain those relationships would start with a region where sediments were deposited, followed by lithification of the sediments to form rock, then the rocks would be subjected to tectonic pressures that folded the rocks. Using relative dating techniques, we know those events occurred in that order, but not when they occurred precisely in time. To add specific dates for the events in the model, geologists can use absolute dating techniques to date the rocks (determine their age). Geologists develop models such as this at locations all across Canada, North America, and around the globe. Each location geologists study may only provide information on Earth history from a short window in time; collectively, however, the information in these models can be used to develop our understanding of processes that have acted on Earth since it first formed. -
The Nature of Lunar Isostasy
45th Lunar and Planetary Science Conference (2014) 1630.pdf THE NATURE OF LUNAR ISOSTASY. Michael M. Sori1 and Maria T. Zuber1. 1Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA ([email protected]). Introduction: One way planetary topography can A key assumption in investigating the role of Pratt be supported is isostatic compensation, in which isostasy by looking at the relationship between crustal overburden pressure of rock is balanced at some depth. density and topography is that the density one observes The regions of the Moon that are not associated with near the surface is representative of the underlying maria or basins are generally isostatically compensated crustal column. We justify that assumption here by [1], an observation that was made when the first noting that calculation of the effective density of the detailed lunar gravity maps were constructed [2] and lunar crust as a function of spherical harmonic degree has held with each subsequently more precise data set considered results in a linear trend [14], supporting the [e.g., 3]. notion of a single-layer crust. There are two models of isostasy commonly Results: We make scatter plots of crustal density considered. In the Airy isostasy model [4], crustal as a function of elevation. One such scatter plot, for thickness is varied such that overburden pressures are the South Pole-Aitken basin, is shown in Figure 1. equal at some depth of compensation. The crust is a Points are sampled in a grid every ~8 km. For each layer of uniform density overlaying a mantle of higher scatter plot, we make a least-squared fit to the data and uniform density.