DOCSLIB.ORG

Newly Identified Strike-Slip Plate Boundary in the Northeastern Arabian Sea

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Newly Identified Strike-Slip Plate Boundary in the Northeastern Arabian Sea Newly identified strike-slip plate boundary in the northeastern Arabian Sea Nina Kukowski* Thies Schillhorn Ernst R. Flueh Katrin Huhn* GEOMAR Forschungszentrum für Marine Geowissenschaften der Christian-Albrechts-Universität zu Kiel, Wischhofstrasse 1-3, D-24148 Kiel, Germany ABSTRACT The first regional swath-bathymetry survey of the Makran accretionary wedge revealed a sinistral strike-slip fault, named herein the Sonne fault, obliquely crossing the wedge and contin- uing into the abyssal plane. This fault separates the western part of the Makran subduction zone where plate boundary events are absent from the eastern part that does show plate boundary seismicity; most events are concentrated along the Sonne fault. Little Murray Ridge (a basement high) and related magnetic anomalies are offset along the Sonne fault. Together, these observa- tions identify the newly discovered Sonne strike-slip fault as a plate boundary that has been active ~2 m.y. This finding suggests that what has been considered the northeasternmost part of the Arabian plate is actually a separate microplate, named herein the Ormara plate, the formation of which resulted from tearing of the Arabian plate along the Sonne fault. With this concept, the different dips of the downgoing plate below the western and eastern parts of the Makran margin and the related different distances between the trench and Quaternary arc volcanic centers can be unequivocally explained. Keywords: plate tectonics, northeastern Arabian Sea, Makran convergent margin, swath bathymetry. INTRODUCTION front occurs along the right-lateral Minab tear fault (Jacob and Quittmeyer, Convergence between the Arabian plate and the Eurasian plate causes 1979). To the east, the Makran subduction zone passes into the sinistral subduction at the Makran convergent margin, offshore Iran and Pakistan. Ornach Nal fault, the boundary between the Eurasian and the Indian plates, Among the Earth’s subduction zones, Makran has the thickest incoming which continues toward the Himalayan suture. The present-day regional sediment pile, as much as 7 km at the deformation front at long 62°E to plate tectonic situation is the result of a complex plate interaction in the past, 63°E. Reflection seismic profiles acquired during the 1970s and 1980s including several stages of convergence, separation, and reaccretion of revealed a huge accretionary wedge formed from a sediment pile of ~3.4 km microplates (Powell, 1979). A convergence zone east of Arabia and north of thickness scraped off from the Arabian plate while the lower sediment sec- the (proto) Owen Fracture Zone was already active prior to the collision tion is underplated or subducted (White and Louden, 1982; Platt et al., between India and Eurasia and probably represented the most continuous 1985; Minshull and White, 1989; Kopp et al., 2000). Early descriptions of tectonic element in the Makran region (Powell, 1979). the Makran prism assumed laterally continuous structures built of imbricate thrust slices (Platt, 1988). A detailed study of the Makran accretionary Zagros wedge—including multibeam swath mapping, wide-angle seismic surveys, 30˚N Thrust EURASIAN PLATE Sultan single-channel reflection seismic surveys, and gravity and magnetic sur- Minab Fault veys—was accomplished during cruise SO 123 (MAMUT: Makran Murray Taftan Bazman Pakistan India Traverse) of the German RV Sonne in autumn 1997 (Flueh et al., 1997). Iran Between the deformation front and landward of the mid-slope terrace, an Fault Nal Ornach Pasni Ormara area of more than 10 000 km2 was systematically mapped. The results Gwadar INDIAN PLATE 26˚N Makran revealed a more complicated image with a complex pattern of accretionary Subduction Zone 42 ridges of limited length and a sinistral strike-slip fault cutting across the 36.5 Murray wedge. In this paper we describe this strike-slip fault and present a thorough Ridge discussion of its regional tectonic significance, as we identify it as the upper relative plate motion (mm/yr) ARABIAN PLATE convergent plate boundary plate expression of a tear fault in the downgoing plate. 22˚N Oman divergent plate boundary PLATE AND REGIONAL TECTONIC FRAME transform fault The Makran subduction zone results from the convergence of the OFZ Quaternary volcanic centers Eurasian plate and the Arabian plate (Fig. 1). West of Makran, the Zagros 54˚E 58˚E 62˚E 66˚E 70˚E thrust marks the continental collision between the Arabian and Eurasian plate. The transition between the Zagros thrust and the Makran deformation Figure 1. Simplified map of present-day plate tectonic framework of Arabian-Indian-Eurasian convergence zone. Dark-shaded rectangle is area covered with swath mapping during cruise SO 123 (cf. Fig. 2). *Present address: GeoForschungsZentrum Potsdam, Telegrafenberg, D-14473 Arrows indicate rate and direction of convergence. For details and refer- Potsdam, Germany. E-mail: [email protected]. ences see text; for all individual Quaternary volcanoes, see Figure 3. Geology; April 2000; v. 28; no. 4; p. 355–358; 5 figures. 355 Lut Helmand 24˚48'N 24˚42'N 24˚36'N 24˚30'N 24˚24'N 24˚18'N 63˚36'E 24˚12'N Sultan erosive canyons 29˚N Taftan 63˚24'E Bazman N 63˚12'E 63˚00'E Pakistan 27˚N Iran 62˚48'E 63˚36'E Pasni Ormara 62˚36'E 63˚24'E Gwadar 0 62˚24'E 63˚12'E -300 25˚N Sonne fault -600 62˚12'E 63˚00'E 0 -900 62˚48'E -1200 Little Murray Ridge -1000 segments strike lines Northern -1500 W 23˚N 62˚36'E a -2000 -1800 t e Dalrymple TroughSouthernMurray Ridge r 62˚24'E -2200 59˚E 61˚E 63˚E 65˚E 67˚E -3000 D e -2500 p Figure 3. Regional tectonic map of Arabian-Indian-Eurasian convergence 62˚12'E 24˚48'N 24˚42'N t 24˚36'N -2800 zone showing distribution of earthquakes (circles; compiled from Byrne 24˚30'N 24˚24'N h 24˚18'N 24˚12'N et al., 1992; Jackson et al., 1995; and U.S. National Earthquake Infor- -3100 A accretionary ridges [m] mation Center data set) and Quaternary onshore volcanoes (triangles; on lower slope -3400 compiled from White, 1984; Dykstra and Birnie, 1979; Afa–ghi and Sa–lek, 1977). Onshore topography is from satellite altimetry; submarine topog- raphy is combined from satellite altimetry and RV Sonne cruise data set. 25˚ 00'N meandering canyons Son 280 Iran Pakistan n e most landward fa 26˚N Gwadar ult accretionary ridge ▲ ▲ ▲ ▲ ▲ ▲ ▲ ▲ ▲ 140 ▲ ▲ ▲ ▲ ▲ ▲ ▲ ▲ ▲ ▲ ▲ ▲ ▲ ▲ ▲ ▲ ▲ ▲ [nT] ▲ ▲ ▲ ▲ ▲ ▲ ▲ ▲ ▲ ▲ ▲ ▲ ▲ ▲ ▲ ▲ ▲ ▲ ▲ 0 ▲ ▲ ▲ ▲ ▲ ▲ ▲ ▲ ▲ ▲ Little Murray Ridge ▲ ▲ ▲ ▲ ▲ ▲ 24˚ 30'N ▲ 24˚N ▲ ▲ ▲ ▲ ▲ ▲ ▲ ▲ ▲ ▲ ▲ magnetic anomaly ▲ ▲ ▲ ▲ ▲ ▲ ▲ ▲ ▲▲ ▲▲ ▲ ▲ ▲▲ ▲▲ ▲ ▲▲ ▲▲ ▲ ▲ ▲ ▲ ▲ ▲ ▲ ▲ ▲ ▲ ▲ ▲ -140 ▲ ▲ ▲ ▲ ▲ deformation front ▲ 1. accretionary ridge ▲ ▲ ▲ ▲ ▲ ▲ ▲ ▲▲ ▲ mid slope terrace deformation front lower slope B 60˚E 62˚E 64˚E 66˚E -280 62˚30'E 63˚00'E 63˚30'E Figure 4. Map of magnetic anomalies in northeastern Arabian Sea. Note Figure 2. A:Three-dimensional perspective, shaded bathymetric image offset in linear anomaly caused by Little Murray Ridge (after Edwards of Makran accretionary wedge, showing Sonne strike-slip fault and ero- et al., 2000). Symbols as in Figure 1. sive canyons crossing wedge. B:Tectonic interpretation showing offset of accretionary ridges and extensional jog of Sonne fault, which may result from some rotation of Ormara plate. constrained. The available seismological data (Byrne et al., 1992) and the different trench to volcano distances in the western and eastern parts of the The age of the subducting oceanic crust facing the Makran wedge is Makran subduction zone imply that the western part of the Arabian slab dips not well determined. Alternative plate reconstructions assume it to be at a steeper angle than its eastern part. Jurassic or older (Whitmarsh, 1979), or of Eocene age (Mountain and Prell, 1990). Ongoing subduction at least since the Late Cretaceous, probably MORPHOLOGY OF THE MAKRAN ACCRETIONARY WEDGE with a continuously thick sediment input, has led to the formation of an AND IDENTIFICATION OF A STRIKE-SLIP FAULT accretionary prism more than 350 km wide with a small taper of about 5° in The Makran accretionary wedge is built by a succession of remarkably the offshore part of the wedge. Currently, only the frontal 100–150 km are steep accretionary ridges of limited length (Fig. 2). Because of the thick sedi- submarine, while the largest part is subaerial. The recent convergence rate ment cover, there is no distinct trench. In the western part of the surveyed area, is about 40 mm/yr, showing a west to east increase of about 15% from a smooth bulge in the western part of the surveyed area is a newly forming ac- 36.5 mm/yr close to the Minab fault to 42 mm/yr in easternmost Makran cretionary ridge in a nascent stage. Its seaward edge marks the actual defor- (DeMets et al., 1990, Fig. 1). The deformation front extends approximately mation front. The first accretionary ridge has a throw of as much as 1200 m. perpendicular to the direction of convergence. Commonly, all following ridges have remarkably steep flanks with slopes of Seismicity in the Makran subduction zone is surprisingly low com- between 9° and 14°, whereas the regional slope is very small (1.5°–2.1°). pared to that at other active margins. However, the Mw 8.1 event in 1945 Actual deformation is taking place along steeply dipping thrusts at the seaward near Pasni revealed the potential for very large interplate thrust earthquakes flanks of all ridges. In between, continuous sedimentation is indicated by (Byrne et al., 1992). Thus, the geometry of the downgoing slab is not well undisturbed layering observed in 3.5 kHz echo soundings (Flueh et al., 1997). 356 GEOLOGY,April 2000 The most prominent tectonic feature, however, is a sinistral strike-slip tion of the offset; farther southeast, the strike line intersects Murray Ridge fault (named the Sonne fault after the research vessel surveying the area) just at the transition between the southern and northern segments.
Load more

Recommended publications
  • Africa-Arabia-Eurasia Plate Interactions and Implications for the Dynamics of Mediterranean Subduction and Red Sea Rifting
    This page added by the GeoPRISMS office. Africa-Arabia-Eurasia plate interactions and implications for the dynamics of Mediterranean subduction and Red Sea rifting Authors: R. Reilinger, B. Hager, L. Royden, C. Burchfiel, R. Van der Hilst Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA USA, [email protected], Tel: (617)253 -7860 This page added by the GeoPRISMS office. Our proposed GeoPRISMS Initiative is based on the premise that understanding the mechanics of plate motions (i.e., the force balance on the plates) is necessary to develop realistic models for plate interactions, including processes at subduction and extensional (rifting) plate boundaries. Important advances are being made with new geologic and geophysical techniques and observations that are providing fundamental insights into the dynamics of these plate tectonic processes. Our proposed research addresses directly the following questions identified in the GeoPRISMS SCD Draft Science Plan: 4.2 (How does deformation across the subduction plate boundary evolve in space and time, through the seismic cycle and beyond?), 4.6 (What are the physical and chemical conditions that control subduction zone initiation and the development of mature arc systems?), and 4.7 (What are the critical feedbacks between surface processes and subduction zone mechanics and dynamics?). It has long been recognized that the Greater Mediterranean region provides a natural laboratory to study a wide range of geodynamic processes (Figure 1) including ocean subduction and continent- continent collision (Hellenic arc, Arabia-Eurasia collision), lithospheric delamination (E Turkey High Plateau, Alboran Sea/High Atlas), back-arc extension (Mediterranean basins, including Alboran, Central Mediterranean, Aegean), “escape” tectonics and associated continental transform faulting (Anatolia, North and East Anatolian faults), and active continental and ocean rifting (East African and northern Red Sea rifting, central Red Sea and Gulf of Aden young ocean rifting).
    [Show full text]
  • The Central Asia Collision Zone: Numerical Modelling of the Lithospheric Structure and the Present-Day Kinematics
    Th e Central Asia collision zone: numerical modelling of the lithospheric structure and the present - day kinematics Lavinia Tunini A questa tesi doctoral està subjecta a l a llicència Reconeixement - NoComercial – SenseObraDerivada 3.0. Espanya de Creative Commons . Esta tesis doctoral está sujeta a la licencia Reconocimiento - NoComercial – SinObraDerivada 3.0. España de Creative Commons . Th is doctoral thesis is license d under the Creative Commons Attribution - NonCommercial - NoDerivs 3.0. Spain License . The Central Asia collision zone: numerical modelling of the lithospheric structure and the present-day kinematics Ph.D. thesis presented at the Faculty of Geology of the University of Barcelona to obtain the Degree of Doctor in Earth Sciences Ph.D. student: Lavinia Tunini 1 Supervisors: Tutor: Dra. Ivone Jiménez-Munt 1 Prof. Dr. Juan José Ledo Fernández 2 Prof. Dr. Manel Fernàndez Ortiga 1 1 Institute of Earth Sciences Jaume Almera 2 Department of Geodynamics and Geophysics of the University of Barcelona This thesis has been prepared at the Institute of Earth Sciences Jaume Almera Consejo Superior de Investigaciones Científicas (CSIC) March 2015 Alla mia famiglia La natura non ha fretta, eppure tutto si realizza. – Lao Tzu Agradecimientos En mano tenéis un trabajo de casi 4 años, 173 páginas que no hubieran podido salir a luz sin el apoyo de quienes me han ayudado durante este camino, permitiendo acabar la Tesis antes que la Tesis acabase conmigo. En primer lugar quiero agradecer mis directores de tesis, Ivone Jiménez-Munt y Manel Fernàndez. Gracias por haberme dado la oportunidad de entrar en el proyecto ATIZA, de aprender de la modelización numérica, de participar a múltiples congresos y presentaciones, y, mientras, compartir unas cervezas.
    [Show full text]
  • A Study on Tectonic and Sedimentology in Order to Fault Rupture Potential in Coasts the Makran Sea
    Open Journal of Geology, 2017, 7, 1269-1286 http://www.scirp.org/journal/ojg ISSN Online: 2161-7589 ISSN Print: 2161-7570 A Study on Tectonic and Sedimentology in Order to Fault Rupture Potential in Coasts the Makran Sea Mohyeddin Ahrari-Roudi Oceanography Department, Marine Sciences Faculty, Chabahar Maritime University, Chabahar, Iran How to cite this paper: Ahrari-Roudi, M. Abstract (2017) A Study on Tectonic and Sedimen- tology in Order to Fault Rupture Potential Makran zone is one of the largest accretionary wedges in the world. This re- in Coasts the Makran Sea. Open Journal of search had used methods such as studies of Office and library, field observa- Geology, 7, 1269-1286. tion and surveying that several field visits, sampling, registered structural evi- https://doi.org/10.4236/ojg.2017.79084 dence, Laboratory studies, Data analysis, interpretation and conclusions. The Received: July 29, 2017 most important objective of this study is assessment of Tectonics and hazard Accepted: August 29, 2017 Potential in Coasts the Oman Sea based on tectonics and sedimentology. The Published: September 1, 2017 northward movement and subduction of Oman oceanic lithosphere beneath Iranian micro-plate at a very shallow angle and at high rate is responsible for Copyright © 2017 by author and Scientific Research Publishing Inc. active orogenesis and uplift. Detailed seismological and geological informa- This work is licensed under the Creative tion in planning is extremely essential to avoid any disaster. It is to be re- Commons Attribution International membered that seismicity does not remain fixed in an area but migrates slow- License (CC BY 4.0).
    [Show full text]
  • Geological Evolution of the Red Sea: Historical Background, Review and Synthesis
    See discussions, stats, and author profiles for this publication at: https://www.researchgate.net/publication/277310102 Geological Evolution of the Red Sea: Historical Background, Review and Synthesis Chapter · January 2015 DOI: 10.1007/978-3-662-45201-1_3 CITATIONS READS 6 911 1 author: William Bosworth Apache Egypt Companies 70 PUBLICATIONS 2,954 CITATIONS SEE PROFILE Some of the authors of this publication are also working on these related projects: Near and Middle East and Eastern Africa: Tectonics, geodynamics, satellite gravimetry, magnetic (airborne and satellite), paleomagnetic reconstructions, thermics, seismics, seismology, 3D gravity- magnetic field modeling, GPS, different transformations and filtering, advanced integrated examination. View project Neotectonics of the Red Sea rift system View project All content following this page was uploaded by William Bosworth on 28 May 2015. The user has requested enhancement of the downloaded file. All in-text references underlined in blue are added to the original document and are linked to publications on ResearchGate, letting you access and read them immediately. Geological Evolution of the Red Sea: Historical Background, Review, and Synthesis William Bosworth Abstract The Red Sea is part of an extensive rift system that includes from south to north the oceanic Sheba Ridge, the Gulf of Aden, the Afar region, the Red Sea, the Gulf of Aqaba, the Gulf of Suez, and the Cairo basalt province. Historical interest in this area has stemmed from many causes with diverse objectives, but it is best known as a potential model for how continental lithosphere first ruptures and then evolves to oceanic spreading, a key segment of the Wilson cycle and plate tectonics.
    [Show full text]
  • Arabian Peninsula from Wikipedia, the Free Encyclopedia Jump to Navigationjump to Search "Arabia" and "Arabian" Redirect Here
    Arabian Peninsula From Wikipedia, the free encyclopedia Jump to navigationJump to search "Arabia" and "Arabian" redirect here. For other uses, see Arabia (disambiguation) and Arabian (disambiguation). Arabian Peninsula Area 3.2 million km2 (1.25 million mi²) Population 77,983,936 Demonym Arabian Countries Saudi Arabia Yemen Oman United Arab Emirates Kuwait Qatar Bahrain -shibhu l-jazīrati l ِش ْبهُ ا ْل َج ِزي َرةِ ا ْلعَ َربِيَّة :The Arabian Peninsula, or simply Arabia[1] (/əˈreɪbiə/; Arabic jazīratu l-ʿarab, 'Island of the Arabs'),[2] is َج ِزي َرةُ ا ْلعَ َرب ʿarabiyyah, 'Arabian peninsula' or a peninsula of Western Asia situated northeast of Africa on the Arabian plate. From a geographical perspective, it is considered a subcontinent of Asia.[3] It is the largest peninsula in the world, at 3,237,500 km2 (1,250,000 sq mi).[4][5][6][7][8] The peninsula consists of the countries Yemen, Oman, Qatar, Bahrain, Kuwait, Saudi Arabia and the United Arab Emirates.[9] The peninsula formed as a result of the rifting of the Red Sea between 56 and 23 million years ago, and is bordered by the Red Sea to the west and southwest, the Persian Gulf to the northeast, the Levant to the north and the Indian Ocean to the southeast. The peninsula plays a critical geopolitical role in the Arab world due to its vast reserves of oil and natural gas. The most populous cities on the Arabian Peninsula are Riyadh, Dubai, Jeddah, Abu Dhabi, Doha, Kuwait City, Sanaʽa, and Mecca. Before the modern era, it was divided into four distinct regions: Red Sea Coast (Tihamah), Central Plateau (Al-Yamama), Indian Ocean Coast (Hadhramaut) and Persian Gulf Coast (Al-Bahrain).
    [Show full text]
  • Seismic Anisotropy and the Mantle Dynamics Beneath the Arabian Plate
    Scholars' Mine Doctoral Dissertations Student Theses and Dissertations Fall 2018 Seismic anisotropy and the mantle dynamics beneath the Arabian plate Saleh Ismail Hassan Qaysi Follow this and additional works at: https://scholarsmine.mst.edu/doctoral_dissertations Part of the Geophysics and Seismology Commons Department: Geosciences and Geological and Petroleum Engineering Recommended Citation Qaysi, Saleh Ismail Hassan, "Seismic anisotropy and the mantle dynamics beneath the Arabian plate" (2018). Doctoral Dissertations. 2727. https://scholarsmine.mst.edu/doctoral_dissertations/2727 This thesis is brought to you by Scholars' Mine, a service of the Missouri S&T Library and Learning Resources. This work is protected by U. S. Copyright Law. Unauthorized use including reproduction for redistribution requires the permission of the copyright holder. For more information, please contact [email protected]. SEISMIC ANISOTROPY AND THE MANTLE DYNAMICS BENEATH THE ARABIAN PLATE by SALEH ISMAIL HASSAN QAYSI A DISSERTATION Presented to the Faculty of the Graduate School of the MISSOURI UNIVERSITY OF SCIENCE AND TECHNOLOGY In Partial Fulfillment of the Requirements for the Degree DOCTOR OF PHILOSOPHY in GEOLOGY AND GEOPHYSICS 2018 Approved by: Kelly Liu, Advisor Stephen Gao Neil L. Anderson Ralph Flori Jr Saad Mogren 2018 Saleh Ismail Hassan Qaysi All Rights Reserve iii PUBLICATION DISSERTATION OPTION This dissertation consists of two articles formatted using the publication option. Paper I, the pages from 3 – 19 were accepted for publication in the Seismological Research Letter on December 19, 2018 under number (SRL-D-18-00144_R1). Paper II, the pages from 20 – 56 are in a preparation to be submitted to a scientific journal. iv ABSTRACT We investigate mantle seismic azimuthal anisotropy and deformation beneath the Arabian Plate and adjacent areas using data from 182 broadband seismic stations which include 157 stations managed by the Saudi Geological Survey.
    [Show full text]
  • Paleozoic Stratigraphy and Petroleum Systems of the Western and Southwestern Deserts of Iraq
    GeoArabia, Vol. 3, No. 2, 1998 Paleozoic Stratigraphy and Petroleum Systems, Iraq Gulf PetroLink, Bahrain Paleozoic Stratigraphy and Petroleum Systems of the Western and Southwestern Deserts of Iraq Adnan A.M. Aqrawi Smedvig Technologies ABSTRACT A stratigraphic scheme for the Paleozoic of the Southwestern Desert of Iraq is proposed based upon the review of recently published data from several deep wells in the western part of the country and from outcrops in other regions in Iraq. The main formations are described in terms of facies distribution, probable age, regional thickness, and correlations with the well-reported Paleozoic successions of the adjacent countries (e.g. Jordan and Saudi Arabia), as well as with the Thrust Zone of North Iraq. The Paleozoic depositional and tectonic evolution of the Western and Southwestern Deserts of Iraq, particularly during Cambrian, Ordovician and Silurian, shows marked similarity to those of eastern Jordan and northern Saudi Arabia. However, local lithological variations, which are due to Late Paleozoic Hercynian tectonics, characterize the Upper Paleozoic sequences. The Lower Silurian marine “hot” shale, 65 meters thick in the Akkas-1 well in the Western Desert, is believed to be the main Paleozoic source rock in the Western and Southwestern Deserts. Additional potential source rocks in this region could be the black shales of the Ordovician Khabour Formation, the Upper Devonian to Lower Carboniferous Ora Shale Formation, and the lower shaly beds of the Upper Permian Chia Zairi Formation. The main target reservoirs are of Ordovician, Silurian, Carboniferous and Permian ages. Similar reservoirs have recently been reported for the Western Desert of Iraq, eastern Jordan and northern Saudi Arabia.
    [Show full text]
  • Rift-Valley-1.Pdf
    R E S O U R C E L I B R A R Y E N C Y C L O P E D I C E N T RY Rift Valley A rift valley is a lowland region that forms where Earth’s tectonic plates move apart, or rift. G R A D E S 6 - 12+ S U B J E C T S Earth Science, Geology, Geography, Physical Geography C O N T E N T S 9 Images For the complete encyclopedic entry with media resources, visit: http://www.nationalgeographic.org/encyclopedia/rift-valley/ A rift valley is a lowland region that forms where Earth’s tectonic plates move apart, or rift. Rift valleys are found both on land and at the bottom of the ocean, where they are created by the process of seafloor spreading. Rift valleys differ from river valleys and glacial valleys in that they are created by tectonic activity and not the process of erosion. Tectonic plates are huge, rocky slabs of Earth's lithosphere—its crust and upper mantle. Tectonic plates are constantly in motion—shifting against each other in fault zones, falling beneath one another in a process called subduction, crashing against one another at convergent plate boundaries, and tearing apart from each other at divergent plate boundaries. Many rift valleys are part of “triple junctions,” a type of divergent boundary where three tectonic plates meet at about 120° angles. Two arms of the triple junction can split to form an entire ocean. The third, “failed rift” or aulacogen, may become a rift valley.
    [Show full text]
  • The Geomorphology of the Makran Trench in the Context of the Geological and Geophysical Settings of the Arabian Sea Polina Lemenkova
    The geomorphology of the Makran Trench in the context of the geological and geophysical settings of the Arabian Sea Polina Lemenkova To cite this version: Polina Lemenkova. The geomorphology of the Makran Trench in the context of the geological and geophysical settings of the Arabian Sea. Geology, Geophysics & Environment, 2020, 46 (3), pp.205- 222. 10.7494/geol.2020.46.3.205. hal-02999997 HAL Id: hal-02999997 https://hal.archives-ouvertes.fr/hal-02999997 Submitted on 11 Nov 2020 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. Distributed under a Creative Commons Attribution| 4.0 International License 2020, vol. 46 (3): 205–222 The geomorphology of the Makran Trench in the context of the geological and geophysical settings of the Arabian Sea Polina Lemenkova Analytical Center; Moscow, 115035, Russian Federation; e-mail: [email protected]; ORCID ID: 0000-0002-5759-1089 © 2020 Author. This is an open access publication, which can be used, distributed and reproduced in any medium according to the Creative Commons CC-BY 4.0 License requiring that the original work has been properly cited. Received: 10 June 2020; accepted: 1 October 2020; first published online: 27 October 2020 Abstract: The study focuses on the Makran Trench in the Arabian Sea basin, in the north Indian Ocean.
    [Show full text]
  • Plate Kinematics of the Afro-Arabian Rift System with an Emphasis on the Afar Depression
    Scholars' Mine Doctoral Dissertations Student Theses and Dissertations Fall 2012 Plate kinematics of the Afro-Arabian Rift System with an emphasis on the Afar Depression Helen Carrie Bottenberg Follow this and additional works at: https://scholarsmine.mst.edu/doctoral_dissertations Part of the Geology Commons, and the Geophysics and Seismology Commons Department: Geosciences and Geological and Petroleum Engineering Recommended Citation Bottenberg, Helen Carrie, "Plate kinematics of the Afro-Arabian Rift System with an emphasis on the Afar Depression" (2012). Doctoral Dissertations. 2237. https://scholarsmine.mst.edu/doctoral_dissertations/2237 This thesis is brought to you by Scholars' Mine, a service of the Missouri S&T Library and Learning Resources. This work is protected by U. S. Copyright Law. Unauthorized use including reproduction for redistribution requires the permission of the copyright holder. For more information, please contact [email protected]. iii iv PLATE KINEMATICS OF THE AFRO-ARABIAN RIFT SYSTEM WITH EMPHASIS ON THE AFAR DEPRESSION, ETHIOPIA by HELEN CARRIE BOTTENBERG A DISSERTATION Presented to the Faculty of the Graduate School of the MISSOURI UNIVERSITY OF SCIENCE & TECHNOLOGY In Partial Fulfillment of the Requirements for the Degree DOCTOR OF PHILOSOPHY in GEOLOGY & GEOPHYSICS 2012 Approved by Mohamed Abdelsalam, Advisor Stephen Gao Leslie Gertsch John Hogan Allison Kennedy Thurmond v 2012 Helen Carrie Bottenberg All Rights Reserved iii PUBLICATION DISSERTATION OPTION This dissertation has been prepared in the style utilized by Geosphere and The Journal of African Earth Sciences. Pages 6-41 and Pages 97-134 will be submitted for separate publications in Geosphere and pages 44-96 will be submitted to Journal of African Earth Sciences iv ABSTRACT This work utilizes the Four-Dimensional Plates (4DPlates) software, and Differential Interferometric Synthetic Aperture Radar (DInSAR) to examine plate-scale, regional- scale and local-scale kinematics of the Afro-Arabian Rift System with emphasis on the Afar Depression in Ethiopia.
    [Show full text]
  • Precambrian Ophiolites of Arabia: a Summary of Geologic Settings U-Pb
    DEPARTMENT OF THE INTERIOR U.S. GEOLOGICAL SURVEY Precambrian ophiolites of Arabia: A summary of geologic settings U-Pb geochronology, lead isotope characteristics, and implications for microplate accretion, kingdom of Saudi Arabia by J. S. Pal lister!/, J. S. StaceyZ/, L. B. Fischer and W. R. Premo Open-File Report Report prepared by the U.S. Geological Survey in cooperation with the Deputy Ministry for Mineral Resources, Saudi Arabia This report is preliminary and has not been reviewed for conformity with U.S. Geological Survey editorial standards and stratigraphic nomenclature. JV U.S. Geological Survey, Denver, CO 2/ U.S. Geological Survey, Menlo Park, CA 1988 CONTENTS PAGE ABSTRACT.................................................. 1 INTRODUCTION.............................................. 2 Ophiolites and the Arabian Shield..................... 2 A note on stratigraphic nomenclature.................. 5 ACKNOWLEDGMENTS........................................... 6 GEOLOGIC AND TECTONIC SETTINGS, SAMPLE DESCRIPTIONS....... 6 Northwest and west-central Arabian Shield............. 7 Jabal Ess ophiolite............................... 7 Jabal al Wask complex............................. 12 Nabt complex and the Kamal intrusion.............. 17 Thurwah ophiolite..................................... 18 Bir Umg complex................................... 21 Nabitah suture zone................................... 25 Bir Tuluhah complex .............................. 25 Ad Dafinah belt .................................. 27 Tathlith and Hamdah
    [Show full text]
  • This Dynamic Earth in January of 1992
    View of the planet Earth from the Apollo spacecraft. The Red Sea, which separates Saudi Arabia from the continent of Africa, is clearly visible at the top. (Photograph courtesy of NASA.) Contents Preface Historical perspective Developing the theory Understanding plate motions "Hotspots": Mantle Some unanswered questions Plate tectonics and people Endnotes thermal plumes 1 of 77 2002-01-01 11:52 This pdf-version was edited by Peter Lindeberg in December 2001. Any deviation from the original text is non-intentional. This book was originally published in paper form in February 1996 (design and coordination by Martha Kiger; illustrations and production by Jane Russell). It is for sale for $7 from: U.S. Government Printing Office Superintendent of Documents, Mail Stop SSOP Washington, DC 20402-9328 or it can be ordered directly from the U.S. Geological Survey: Call toll-free 1-888-ASK-USGS Or write to USGS Information Services Box 25286, Building 810 Denver Federal Center Denver, CO 80225 303-202-4700; Fax 303-202-4693 ISBN 0-16-048220-8 Version 1.08 The online edition contains all text from the original book in its entirety. Some figures have been modified to enhance legibility at screen resolutions. Many of the images in this book are available in high resolution from the USGS Media for Science page. USGS Home Page URL: http://pubs.usgs.gov/publications/text/dynamic.html Last updated: 01.29.01 Contact: [email protected] 2 of 77 2002-01-01 11:52 In the early 1960s, the emergence of the theory of plate tectonics started a revolution in the earth sciences.
    [Show full text]