Quantification of Erosion and Uplift in a Rising Orogen—A Large-Scale Perspective
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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). -
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. -
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. -
The Easternmost Occurrence of Mammut Pacificus (Proboscidea: Mammutidae), Based on a Partial Skull from Eastern Montana, USA
The easternmost occurrence of Mammut pacificus (Proboscidea: Mammutidae), based on a partial skull from eastern Montana, USA Andrew T. McDonald1, Amy L. Atwater2, Alton C. Dooley Jr1 and Charlotte J.H. Hohman2,3 1 Western Science Center, Hemet, CA, United States of America 2 Museum of the Rockies, Montana State University, Bozeman, MT, United States of America 3 Department of Earth Sciences, Montana State University, Bozeman, MT, United States of America ABSTRACT Mammut pacificus is a recently described species of mastodon from the Pleistocene of California and Idaho. We report the easternmost occurrence of this taxon based upon the palate with right and left M3 of an adult male from the Irvingtonian of eastern Montana. The undamaged right M3 exhibits the extreme narrowness that characterizes M. pacificus rather than M. americanum. The Montana specimen dates to an interglacial interval between pre-Illinoian and Illinoian glaciation, perhaps indicating that M. pacificus was extirpated in the region due to habitat shifts associated with glacial encroachment. Subjects Biogeography, Evolutionary Studies, Paleontology, Zoology Keywords Mammut pacificus, Mammutidae, Montana, Irvingtonian, Pleistocene INTRODUCTION Submitted 7 May 2020 The recent recognition of the Pacific mastodon (Mammut pacificus (Dooley Jr et al., 2019)) Accepted 3 September 2020 as a new species distinct from and contemporaneous with the American mastodon Published 16 November 2020 (M. americanum) revealed an unrealized complexity in North American mammutid Corresponding author evolution during the Pleistocene. Dooley Jr et al. (2019) distinguished M. pacificus from Andrew T. McDonald, [email protected] M. americanum by a suite of dental and skeletal features: (1) upper third molars (M3) Academic editor and lower third molars (m3) much narrower relative to length in M. -
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. -
Fluvial Response to Rapid Episodic Erosion by Earthquake and Typhoons, Tachia River, Central Taiwan
Geomorphology 175–176 (2012) 126–138 Contents lists available at SciVerse ScienceDirect Geomorphology journal homepage: www.elsevier.com/locate/geomorph Fluvial response to rapid episodic erosion by earthquake and typhoons, Tachia River, central Taiwan Michelle Y.-F. Huang ⁎, David R. Montgomery Department of Earth and Space Sciences, University of Washington, Seattle, WA 98195-1310, USA article info abstract Article history: Analysis of typhoon- and earthquake-triggered landsliding and fluvial response in the Tachia River, central Received 28 January 2012 Taiwan, documents highly episodic sediment supply over decade to century timescales. Landslide data Received in revised form 2 July 2012 from the Chi-Chi earthquake (1999) and subsequent typhoons (2001, 2004, and 2005) quantify the sediment Accepted 5 July 2012 supply from these events. Fluvial response was investigated by decadal-scale and century-scale longitudinal Available online 16 July 2012 river profile data spanning 1904 to 2008 and by sediment delivery recorded in suspended sediment load and reservoir sedimentation data. Our results show that the different time periods of satellite images and aerial Keywords: fi Landslide photographs used in previous studies make it dif cult to unambiguously identify the causes of landslides pre- Earthquake viously attributed by some studies to the effects of the Chi-Chi earthquake rather than subsequent high inten- Typhoon sity precipitation. In response to significant variability in sediment delivery from hillslopes, century-scale Erosion profile variation data indicate substantial bed surface elevation change of 2.6±6.7 m, and decade-scale Channel response bed surface elevation change of 1.1±3.3 m. Since 1993, the downstream reaches incised in response to bedload sediment trapping by reservoirs while headwater reaches aggraded in response to increased sedi- ment delivery from uplands. -
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. -
Glacial Isostatic Adjustment and Sea-Level Change – State of the Art Report Technical Report TR-09-11
Glacial isostatic adjustment and sea-level change – State of the art report Glacial isostatic adjustment and sea-level change Technical Report TR-09-11 Glacial isostatic adjustment and sea-level change State of the art report Pippa Whitehouse, Durham University April 2009 Svensk Kärnbränslehantering AB Swedish Nuclear Fuel and Waste Management Co Box 250, SE-101 24 Stockholm Phone +46 8 459 84 00 TR-09-11 ISSN 1404-0344 CM Gruppen AB, Bromma, 2009 Tänd ett lager: P, R eller TR. Glacial isostatic adjustment and sea-level change State of the art report Pippa Whitehouse, Durham University April 2009 This report concerns a study which was conducted for SKB. The conclusions and viewpoints presented in the report are those of the author and do not necessarily coincide with those of the client. A pdf version of this document can be downloaded from www.skb.se. Preface This document contains information on the process of glacial isostatic adjustment (GIA) and how this affects sea-level and shore-line displacement, and the methods which are employed by researchers to study and understand these processes. The information will be used in e.g. the report “Climate and climate-related issues for the safety assessment SR-Site”. Stockholm, April 2009 Jens-Ove Näslund Person in charge of the SKB climate programme Contents 1 Introduction 7 1.1 Structure and purpose of this report 7 1.2 A brief introduction to GIA 7 1.2.1 Overview/general description 7 1.2.2 Governing factors 8 1.2.3 Observations of glacial isostatic adjustment 9 1.2.4 Time scales 9 2 Glacial -
Layer Cake Geology
LAYER CAKE GEOLOGY John R. Wagner Department of Earth Sciences Clemson University Clemson, S.C. 29634-1908 Level: Grades 4 - 6 Can be modified for use with Grades 2 - 3. Estimated Time Required: 50 - 60 minutes Anticipated Learning Outcomes • Students will understand the mechanisms by which folds and faults occur within the earth's crust. • Students will recognize the difference in behavior between brittle and ductile rocks. • Students will predict the structure likely to result from application of various forces to layered rocks. • Students will interpret "core samples" to determine rock structures beneath the land surface. • Students will learn the meaning of the following geologic terms: fold, fault, brittle, ductile, fracture, and core samples. Background No prior knowledge of geology is required. However, the teacher should introduce the two basic concepts of layered rock: superposition (oldest layer at bottom, youngest at top) and original horizontality (sediments deposited in horizontal layers until some force changes their tilt or orientation). Materials • Multiple-layer cake prepared according to the following instructions: 1. Use moist pound cake (or other dense, coherent cake) mix. (One mix is sufficient for whole class activity if layers are made thin enough.) 2. Bake four to six thin cakes, (each between 0.5 and 2.0 cm thick), each a different color (mix in food coloring before baking). Use square or rectangular pans. 3. Stack the cakes in any order. Apply icing (of any kind) between the layers but not on the top or sides of the cake. • Knife for cutting cake • Three transparent plastic tubes (diameter between 1 and 2 centimeters) at least as long as the cake is high. -
Isostasy and Flexure of the Lithosphere
Isostasy and Flexure of the Lithosphere A. B. WATTS Department of Earth Sciences, Oxford University Oxford, United Kingdom PUBLISHED BY THE PRESS SYNDICATE OF THE UNIVERSITY OF CAMBRIDGE The Pitt Building, Trumpington Street, Cambridge, United Kingdom CAMBRIDGE UNIVERSITY PRESS The Edinburgh Building, Cambridge, United Kingdom http://www.cup.cam.ac.uk 40 West 20th Street, New York, NY 10011–4211, USA http://www.cup.org 10 Stamford Road, Oakleigh, Melbourne 3166, Australia Ruiz de Alarco´ n 13, 28014 Madrid, Spain # Cambridge University Press 2001 This book is in copyright. Subject to statutory exception and to the provisions of relevant collective licensing agreements, no reproduction of any part may take place without the written permission of Cambridge University Press. First published 2001 Printed in the United States of America Typeface Times Ten PS 10/12.5 System 3B2 [KW] A catalogue record for this book is available from the British Library Library of Congress Cataloging-in-Publication Data Watts, A. B. (Anthony Brian), 1945– Isostasy and flexure of the lithosphere / A. B. Watts. p. cm. Includes bibliographical references and index. ISBN 0-521-62272 – ISBN 0-521-00600-7 (pb) 1. Isostasy. 2. Earth – Crust. I. Title. QE511.W38 2001 551 – dc21 00-065146 ISBN 0 521 62272 7 hardback ISBN 0 521 00600 7 paperback Contents Preface page xi Acknowledgments xiii Notation xvii 1 The Development of the Concept of Isostasy 1 1.1 Introduction 1 1.2 First Isostatic Ideas 2 1.3 The Deflection of the Vertical in India 9 1.4 Isostasy According to Airy -
Clay Minerals and Detrital Material in Paleocene–Eocene Biogenic Siliceous Rocks (Sw Western Siberia): Implications for Volcanic and Depositional Environment Record
geosciences Article Clay Minerals and Detrital Material in Paleocene–Eocene Biogenic Siliceous Rocks (Sw Western Siberia): Implications for Volcanic and Depositional Environment Record Pavel Smirnov 1,2,*, Oksana Deryagina 1,3, Nadezhda Afanasieva 4, Maxim Rudmin 5 and Hans-Jürgen Gursky 2 1 Laboratory of Sedimentology and Paleobiosphere Evolution, University of Tyumen, Volodarskogo St. 6, 625003 Tyumen, Russia; [email protected] 2 Institute of Geology and Paleontology, Clausthal University of Technology, Adolph-Roemer-Straße 2A, 38678 Clausthal-Zellerfeld, Germany; [email protected] 3 Laboratory of lithological and petrophysical studies of rocks, West Siberian Geological Center, Surgutskaya St. 11/2, 625002 Tyumen, Russia 4 Institute of Geology and Petroleum Technology, Kazan Federal University, Kremlevskaya St. 4/5, 420008 Kazan Russia; [email protected] 5 Division for Geology, National Research Tomsk Polytechnic University, Lenina St. 30, 634050 Tomsk, Russia; [email protected] * Correspondence: [email protected]; Tel.: +7-922-483-80-90 Received: 10 February 2020; Accepted: 27 April 2020; Published: 29 April 2020 Abstract: The paper presents the results of a study on clay minerals and detrital material of biosiliceous rocks (Paleocene–Eocene) from three sections in the Transuralian region. The authigenic processes in sediments resulted in the formation of dioctahedral clay minerals (illite, smectite) and insignificant amounts of sulfide phases (pyrite, hydrotroillite). Detrital minerals from the studied diatomites and diatomaceous clays often have a subangular and semi-rounded habit that is evidence of a low degree alteration of the sedimentary material in the provenance areas. The high degree of preservation of the bioclastic debris and the transformation of the limited volcanogenic substratum in clay minerals apparently was possible by initial burial diagenesis. -
Estimating Regional Flood Discharge During Palaeocene-Eocene Global
www.nature.com/scientificreports OPEN Estimating regional food discharge during Palaeocene-Eocene global warming Received: 8 January 2018 Chen Chen1, Laure Guerit1,2, Brady Z. Foreman 3, Hima J. Hassenruck-Gudipati4, Accepted: 6 August 2018 Thierry Adatte5, Louis Honegger1, Marc Perret1, Appy Sluijs6 & Sébastien Castelltort 1 Published: xx xx xxxx Among the most urgent challenges in future climate change scenarios is accurately predicting the magnitude to which precipitation extremes will intensify. Analogous changes have been reported for an episode of millennial-scale 5 °C warming, termed the Palaeocene-Eocene Thermal Maximum (PETM; 56 Ma), providing independent constraints on hydrological response to global warming. However, quantifying hydrologic extremes during geologic global warming analogs has proven difcult. Here we show that water discharge increased by at least 1.35 and potentially up to 14 times during the early phase of the PETM in northern Spain. We base these estimates on analyses of channel dimensions, sediment grain size, and palaeochannel gradients across the early PETM, which is regionally marked by an abrupt transition from overbank palaeosol deposits to conglomeratic fuvial sequences. We infer that extreme foods and channel mobility quickly denuded surrounding soil-mantled landscapes, plausibly enhanced by regional vegetation decline, and exported enormous quantities of terrigenous material towards the ocean. These results support hypotheses that extreme rainfall events and associated risks of fooding increase with global warming at similar, but potentially at much higher, magnitudes than currently predicted. Alluvial deposits within the Tremp-Graus Basin of northern Spain (~35°N palaeolatitude) show a change from strata dominated by overbank palaeosols to an anomalously thick and widespread, conglomeratic fuvial unit that coincides with the early phase of the PETM1–3.