DOCSLIB.ORG

Anomalously Fast Convergence of India and Eurasia Caused by Double Subduction

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Anomalously Fast Convergence of India and Eurasia Caused by Double Subduction LETTERS PUBLISHED ONLINE: 4 MAY 2015 | DOI: 10.1038/NGEO2418 Anomalously fast convergence of India and Eurasia caused by double subduction Oliver Jagoutz1*, Leigh Royden1, Adam F. Holt2 and Thorsten W. Becker2 Before its collision with Eurasia1–5, the Indian Plate moved The existence of this Trans-Tethyan subduction system is 1 20 rapidly, at rates exceeding 140 mm yr− for a period of 20 mil- consistent with the presence of two relict slabs below India . At lion years1,3–7. This motion is 50 to 100% faster than the maxi- the longitude of the Himalaya, palaeomagnetic data show that mum sustained rate of convergence of the main tectonic plates in the Cretaceous, rocks of the Trans-Tethyan subduction system today8. The cause of such high rates of convergence is unclear (Kohistan–Ladakh Arc and ophiolites of the Tsangpo suture zone) and not reproduced by numerical models9,10. Here we show formed near the equator18,21,22, whereas the magmatic rocks devel- that existing geological data11,12 support the existence of two, oped along the southern margin of Eurasia (Karakoram–Gangdese almost parallel, northward dipping subduction zones between Arc, labelled Km, G and M in Fig.1 ) formed at ∼20◦–25◦ N (ref. 23). the Indian and Eurasian plates, during the Early Cretaceous This indicates that the two subduction systems were separated by an period. We use a quantitative model to show that the combined approximately 1,500–3,000 km wide oceanic plate, here called the pull of two subducting slabs can generate anomalously rapid Kshiroda Plate (Fig.1 ). convergence between India and Eurasia. Furthermore, in our Before the initiation of spreading in the Indian Ocean simulations a reduction in length of the southern subduction (∼120–130 Myr ago (ref.5 )), a spreading ridge must have system, from about 10,000 to 3,000 km between 90 and existed between India and Eurasia to accommodate subduction 80 million years ago, reduced the viscous pressure between in the Neo-Tethys whereas little convergence occurred between the subducting slabs and created a threefold increase in plate the southern continents and Eurasia5. We place this ridge south convergence rate between 80 and 65 million years ago. Rapid of the Trans-Tethyan subduction system because spreading along convergence ended 50 million years ago, when the Indian Plate its eastern extension is needed north of Australia to prevent its collided with the southern subduction system. Collision of India northward motion until the Woyla and Sumatra arcs become with Eurasia and the northern subduction system had little inactive at 90 Myr. eect on plate convergence rates before 40 million years ago. The timing of subduction along the Trans-Tethyan subduction We conclude that the number and geometry of subduction system is crucial for understanding the convergence history of India systems has a strong influence on plate migration rates. and Eurasia. From the Semail ophiolite westwards, intra-oceanic The northward motion of India from the Early Cretaceous subduction ended at ∼90–80 Myr when the arc collided with the period to the Early Cenozoic era is related to the subduction of northern margin of Arabia15 (Fig.1 ). In Sumatra, intra-oceanic oceanic lithosphere north of India, which consumed the Neo- subduction ended at ∼90 Myr, with northward obduction of the Tethys Ocean13, and to seafloor spreading south of India, which Woyla Arc onto continental crust12. Andean subduction in Sumatra created the Indian Ocean14. During the Cretaceous to Early Tertiary also ended at about the same time12. period, multiple subduction systems operated within the Neo- In contrast, subduction along the central portion of the Trans- Tethys, including a north-dipping subduction boundary beneath the Tethyan subduction system continued along an approximately southern margin of Eurasia (for example, ref. 11) and, as proposed 3,000 km segment that formed the northern margin of the Indian here, a second, intra-oceanic `Trans-Tethyan' subduction system Plate (Fig.1 )17. Evidence for continued subduction until ∼50 Myr is that extended from the eastern Mediterranean to Indonesia, and well established in the western Himalaya17. New geochronological perhaps beyond (Fig.1 )12. and isotopic data from the western Himalaya17 show a ∼50 Myr The preserved geologic entities that make up this Cretaceous to collision of the Indian subcontinent with the Kohistan–Ladakh Early Tertiary `Trans-Tethyan subduction system' are, from west to Arc and a ∼40 Myr collision of the amalgamated arc-continent east: the Antalya nappes and Cyprus ophiolite of southern Turkey15; with Eurasia. This collisional history is also consistent with the peri-Arabian ophiolites in the Middle East (labelled PA in Fig.1 ) palaeomagnetic data from the Kohistan–Ladakh Arc18,21, and and the Semail ophiolite in Oman15 (labelled Sm); ophiolitic and with the timing of two major tectonic events observed in the arc sequences of western Pakistan (Bela, Waziristan ophiolites16); Indian Ocean2. the Kohistan–Ladakh Arc (labelled K) and associated ophiolites of In the central to eastern Himalaya, most of the rocks related the western Himalaya17 (labelled X); supra-subduction ophiolites, to the Trans-Tethyan subduction system are missing, but sporadic forearc sequences and oceanic mélange sequences of the Tsangpo remnants of this subduction system remain19. In particular, an intra- suture zone in the central and southern Himalaya18,19; ophiolitic and oceanic mélange sequence near Xigaze yields Palaeocene fossil ages magmatic remnants in the Andaman Islands and Sumatra (Woyla that attest to intra-oceanic subduction into the Early Tertiary18,24,25. Arc12 (W); Fig.1 ). By at least the mid-Cretaceous, this subduction Figure3 shows plate circuit data constraining the convergence boundary seems to have been everywhere north-dipping12,15 (Fig.2 ). history of India and Eurasia3,4. Because Eurasia and Antarctica 1Department of Earth, Atmospheric and Planetary Sciences, MIT, Cambridge, Massachusetts 01890, USA. 2Department of Earth Sciences, University of Southern California, Los Angeles, California 90089, USA. *e-mail: [email protected] NATURE GEOSCIENCE | VOL 8 | JUNE 2015 | www.nature.com/naturegeoscience 475 © 2015 Macmillan Publishers Limited. All rights reserved LETTERS NATURE GEOSCIENCE DOI: 10.1038/NGEO2418 a Km G Today K X PA M India Africa Sm Arabia W b c 90 Myr 80 Myr Eurasia Eurasia Km 30° N 30° N G M Kshiroda PA Kshiroda Plate Plate K Africa Africa Sm X 0° 0° W Neo-Tethyan Ocean Latitude Latitude ° ° India 30 S India 30 S WR Indian Ocean Australia Australia Antarctica 0° 60° E 120° E 0° 60° E 120° E Longitude Longitude d e 50 Myr 40 Myr Eurasia Eurasia 30° N 30° N India Africa India Africa 0° 0° CIR Latitude Latitude WR CIR WR 30° S 30° S SWIR SEIR Australia SEIR Australia SWIR Antarctica Antarctica 0° 60° E 120° E 0° 60° E 120° E Longitude Longitude Figure 1 | Present day remnants of two subduction zones, and plate tectonic reconstructions for 90–40 Myr. a, Rocks related to subduction active after 80 Myr are red (Trans-Tethyan intra-oceanic system) and yellow (arc rocks of the Cretaceous subduction system of southern Eurasia). Rocks related to subduction that terminated before 80 Myr are white (both belts). Arrows show the sense of motion along the eastern and western margins of the Indian Plate after 80 Myr. b–e, Reconstructions of Neo-Tethyan plate boundaries; active boundaries shown in red, boundaries becoming extinct in grey. Red triangles indicate subduction, plain lines indicate spreading ridges and transform boundaries. remained relatively stationary, rates of opening of the Indian To investigate the effects of double subduction and the reduction Ocean are nearly identical to rates of India–Eurasia convergence, in trench length of the subduction plate, we employ quantitative, further constraining their pre-collisional history1. Before 80 Myr, three-dimensional models of coupled double subduction (that convergence rates are not constrained by reliable sea floor is, no spreading ridges present between the subduction systems, magnetic anomalies, so we use palaeolatitude data to constrain see Supplementary Fig. e1). Methods gives brief descriptions and convergence rates23. benchmarking exercises for double subduction computed using two Figure3 shows that, contemporaneous with the reduction in methods: an extension of the semi-analytic subduction technique trench length of the Trans-Tethyan subduction system, India– described by ref. 26 (fast analytical subduction technique (FAST), Eurasia convergence rates began to increase rapidly. Simultaneously, described in detail in the Supplementary Information) and a fully the Wharton Ridge (labelled WR in Fig.1 ) transform system numerical computation (an extension of CitcomCU; for example, initiated with a dominantly right-slip sense, forming the eastern ref. 27). The results of these techniques are very similar, indicating boundary of the Indian Plate (Fig.1 ) whereas spreading and left- that the physics governing slab and plate motion is captured slip on the Southwest Indian Ridge (SWIR) and Central Indian consistently. We choose to model the India–Eurasia convergence Ridge (CIR) accommodated divergence between India, Africa using FAST, which includes three-dimensional asthenospheric flow, and Madagascar5. topographic loading, slab bending and thrust interface coupling, 476 NATURE GEOSCIENCE | VOL 8 | JUNE 2015 | www.nature.com/naturegeoscience © 2015 Macmillan Publishers Limited. All rights reserved NATURE GEOSCIENCE DOI: 10.1038/NGEO2418 LETTERS 120 Myr Kshiroda Plate Indian Plate Eurasia India 90 Myr 60 Myr Age of oceanic lithosphere (Myr) 04020 60 80 100 5,000 km Figure 2 | Cross-sections of double subduction in the Tethys region. Slab geometries and distances between subduction systems and continents correspond to results of the model discussed in the text. The sea floor ages shown are those used as initial conditions in the model (at 120 Myr) and illustrate ageing of the oceanic lithosphere as derived from the model results. The yellow and red volcanoes indicate the volcanic arcs of the Southern Eurasian Margin and the Trans Tethyan subduction system, respectively.
Load more

Recommended publications
  • India-Asia Collision and the Cenozoic Slowdown of the Indian Plate
    JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 115, B03410, doi:10.1029/2009JB006634, 2010 Click Here for Full Article India-Asia collision and the Cenozoic slowdown of the Indian plate: Implications for the forces driving plate motions Alex Copley,1 Jean-Philippe Avouac,1 and Jean-Yves Royer2 Received 21 May 2009; revised 12 August 2009; accepted 25 September 2009; published 17 March 2010. [1] The plate motion of India changed dramatically between 50 and 35 Ma, with the rate of convergence between India and Asia dropping from 15 to 4 cm/yr. This change is coincident with the onset of the India-Asia collision, and with a rearrangement of plate boundaries in the Indian Ocean. On the basis of a simple model for the forces exerted upon the edges of the plate and the tractions on the base of the plate, we perform force balance calculations for the precollision and postcollision configurations. We show that the observed Euler poles for the Indian plate are well explained in terms of their locations and magnitudes if (1) the resistive force induced by mountain building in the Himalaya-Tibet area is 5–6 Â 1012 N/m, (2) the net force exerted upon the Indian plate by subduction zones is similar in magnitude to the ridge-push force (2.5 Â 1012 N/m), and (3) basal tractions exert a resisting force that is linearly proportional to the plate velocity in the hot spot reference frame. The third point implies an asthenospheric viscosity of 2–5 Â 1019 Pa s, assuming a thickness of 100–150 km.
    [Show full text]
  • Greater India Basin Hypothesis and a Two-Stage Cenozoic Collision Between India and Asia
    Greater India Basin hypothesis and a two-stage Cenozoic collision between India and Asia Douwe J. J. van Hinsbergena,b,1, Peter C. Lippertc,d, Guillaume Dupont-Nivete,f,g, Nadine McQuarrieh, Pavel V. Doubrovinea,b, Wim Spakmani, and Trond H. Torsvika,b,j,k aPhysics of Geological Processes, University of Oslo, Sem Sælands vei 24, NO-0316 Oslo, Norway; bCenter for Advanced Study, Norwegian Academy of Science and Letters, Drammensveien 78, 0271 Oslo, Norway; cDepartment of Geosciences, University of Arizona, Tucson, AZ 85721; dDepartment of Earth and Planetary Sciences, University of California, Santa Cruz, CA 95064; eGéosciences Rennes, Unité Mixte de Recherche 6118, Université de Rennes 1, Campus de Beaulieu, 35042 Rennes Cedex, France; fPaleomagnetic Laboratory Fort Hoofddijk, Department of Earth Sciences, University of Utrecht, Budapestlaan 17, 3584 CD, Utrecht, The Netherlands; gKey Laboratory of Orogenic Belts and Crustal Evolution, Ministry of Education, Peking University, Beijing 100871, China; hDepartment of Geology and Planetary Science, University of Pittsburgh, Pittsburgh, PA 15260; iDepartment of Earth Sciences, University of Utrecht, Budapestlaan 4, 3584 CD, Utrecht, The Netherlands; jCenter for Geodynamics, Geological Survey of Norway, Leiv Eirikssons vei 39, 7491 Trondheim, Norway; and kSchool of Geosciences, University of the Witwatersrand, WITS 2050, Johannesburg, South Africa Edited by B. Clark Burchfiel, Massachusetts Institute of Technology, Cambridge, MA, and approved March 29, 2012 (received for review October 19, 2011) Cenozoic convergence between the Indian and Asian plates pro- (Fig. 2; SI Text) as well as with an abrupt decrease in India–Asia duced the archetypical continental collision zone comprising the convergence rates beginning at 55–50 Ma, as demonstrated by Himalaya mountain belt and the Tibetan Plateau.
    [Show full text]
  • Himalaya - Southern-Tibet: the Typical Continent-Continent Collision Orogen
    237 Himalaya - Southern-Tibet: the typical continent-continent collision orogen When an oceanic plate is subducted beneath a continental lithosphere, an Andean mountain range develops on the edge of the continent. If the subducting plate also contains some continental lithosphere, plate convergence eventually brings both continents into juxtaposition. While the oceanic lithosphere is relatively dense and sinks into the asthenosphere, the greater sialic content of the continental lithosphere ascribes positive buoyancy in the asthenosphere, which hinders the continental lithosphere to be subducted any great distance. Consequently, a continental lithosphere arriving at a trench will confront the overriding continent. Rapid relative convergence is halted and crustal shortening forms a collision mountain range. The plane marking the locus of collision is a suture, which usually preserves slivers of the oceanic lithosphere that formerly separated the continents, known as ophiolites. The collision between the Indian subcontinent and what is now Tibet began in the Eocene. It involved and still involves north-south convergence throughout southern Tibet and the Himalayas. This youthful mountain area is the type example for studies of continental collision processes. The Himalayas Location The Himalayas form a nearly 3000 km long, 250-350 km wide range between India to the south and the huge Tibetan plateau, with a mean elevation of 5000 m, to the north. The Himalayan mountain belt has a relatively simple, arcuate, and cylindrical geometry over most of its length and terminates at both ends in nearly transverse syntaxes, i.e. areas where orogenic structures turn sharply about a vertical axis. Both syntaxes are named after the main peaks that tower above them, the Namche Barwa (7756 m) to the east and the Nanga Parbat (8138 m) to the west, in Pakistan.
    [Show full text]
  • Al Qaeda in the Indian Subcontinent: a New Frontline in the Global Jihadist Movement?” the International Centre for Counter- Ter Rorism – the Hague 8, No
    AL-QAEDA IN THE INDIAN SUBCONTINENT: The Nucleus of Jihad in South Asia THE SOUFAN CENTER JANUARY 2019 AL-QAEDA IN THE INDIAN SUBCONTINENT: THE NUCLEUS OF JIHAD IN SOUTH ASIA !1 AL-QAEDA IN THE INDIAN SUBCONTINENT: THE NUCLEUS OF JIHAD IN SOUTH ASIA AL-QAEDA IN THE INDIAN SUBCONTINENT (AQIS): The Nucleus of Jihad in South Asia THE SOUFAN CENTER JANUARY 2019 !2 AL-QAEDA IN THE INDIAN SUBCONTINENT: THE NUCLEUS OF JIHAD IN SOUTH ASIA CONTENTS List of Abbreviations 4 List of Figures & Graphs 5 Key Findings 6 Executive Summary 7 AQIS Formation: An Affiliate with Strong Alliances 11 AQIS Leadership 19 AQIS Funding & Finances 24 Wahhabization of South Asia 27 A Region Primed: Changing Dynamics in the Subcontinent 31 Global Threats Posed by AQIS 40 Conclusion 44 Contributors 46 About The Soufan Center (TSC) 48 Endnotes 49 !3 AL-QAEDA IN THE INDIAN SUBCONTINENT: THE NUCLEUS OF JIHAD IN SOUTH ASIA LIST OF ABBREVIATIONS AAI Ansar ul Islam Bangladesh ABT Ansar ul Bangla Team AFPAK Afghanistan and Pakistan Region AQC Al-Qaeda Central AQI Al-Qaeda in Iraq AQIS Al-Qaeda in the Indian Subcontinent FATA Federally Administered Tribal Areas HUJI Harkat ul Jihad e Islami HUJI-B Harkat ul Jihad e Islami Bangladesh ISI Pakistan’s Inter-Services Intelligence ISKP Islamic State Khorasan Province JMB Jamaat-ul-Mujahideen Bangladesh KFR Kidnap for Randsom LeJ Lashkar e Jhangvi LeT Lashkar e Toiba TTP Tehrik-e Taliban Pakistan !4 AL-QAEDA IN THE INDIAN SUBCONTINENT: THE NUCLEUS OF JIHAD IN SOUTH ASIA LIST OF FIGURES & GRAPHS Figure 1: Map of South Asia 9 Figure 2:
    [Show full text]
  • The East Asian Jigsaw Puzzle Pangaea at Risk? from Neville Haile
    192 Nature Vol. 293 17 September 1981 ment with the known seismic refraction (Business and Technological Systems, Inc.) pretation of long-wavelength crustal fields and heat flow data. His group believes that magnetization model for the United States, in terms of a geological/geophysical the region is the site of a late Precambrian derived from Magsat scalar data, had much model, promises to contribute significantly rift which was reactivated in the Mesozoic better resolution than that using POGO to our understanding of the Earth's crust. to form an aulacogen and its model data. In the older disciplines of main-field involves thinning of the upper crust and an Although preliminary, the results dis­ modelling and studies of external fields, increase in density in the lower crust. The cussed at the meeting indicate that sep­ there are significant new developments in magnetic low is accounted for by either an aration of the measured field into its core, both analytical techniques and in our isotherm upwarp or, less likely, a litho­ crustal and external 'components' is being understanding of the physics of the field logical variation in the crust. Mayhew's achieved. The newest discipline, inter- sources. 0 The East Asian jigsaw puzzle Pangaea at risk? from Neville Haile UNTIL fairly recently, reconstructions of the world palaeogeography followed Wegener in showing Eurasia, excluding the Indian subcontinent, as a single block, with the Malay Peninsula and part or all of the Indonesian Archipelago depending from it and looking rather vulnerablel ,2. Other world palaeogeo­ graphical maps simply omit South-east Asia and most of China (see the figure)3,4.
    [Show full text]
  • Late Paleozoic and Mesozoic Evolution of the Lhasa Terrane in the Xainza MARK Area of Southern Tibet
    Tectonophysics 721 (2017) 415–434 Contents lists available at ScienceDirect Tectonophysics journal homepage: www.elsevier.com/locate/tecto Late Paleozoic and Mesozoic evolution of the Lhasa Terrane in the Xainza MARK area of southern Tibet ⁎ Suoya Fana,b, , Lin Dinga, Michael A. Murphyb, Wei Yaoa, An Yinc a Key Laboratory of Continental Collision and Plateau Uplift, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100101, China b Department of Earth and Atmospheric Sciences, University of Houston, Houston, TX 77204, USA c Department of Earth, Planetary, and Space Sciences, University of California, Los Angeles, CA 90095-1567, USA ARTICLE INFO ABSTRACT Keywords: Models for the Mesozoic growth of the Tibetan plateau describe closure of the Bangong Ocean resulting in Lhasa terrane accretion of the Lhasa terrane to the Qiangtang terrane along the Bangong-Nuijiang suture zone (BNSZ). Shortening However, a more complex history is suggested by studies of ophiolitic melanges south of the BNSZ “within” the Foreland basin Lhasa terrane. One such mélange belt is the Shiquanhe-Namu Co mélange zone (SNMZ) that is coincident with Suture zone the Geren Co-Namu Co thrust (GNT). To better understand the structure, age, and provenance of rocks exposed Provenance along the SNMZ we conducted geologic mapping, sandstone petrography, and U-Pb zircon geochronology of Geochronology rocks straddling the SNMZ. The GNT is north-directed and places Paleozoic strata against the Yongzhu ophiolite and Cretaceous strata along strike. A gabbro in the Yongzhu ophiolite yielded a U-Pb zircon age of 153 Ma. Detrital zircon age data from Permian rocks in the hanging wall suggests that the Lhasa terrane has affinity with the Himalaya and Qiangtang, rather than northwest Australia.
    [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]
  • J Indian Subcontinent
    Intercontinental relationship Europe - Africa and the Indian Subcontinent 45 Jan van der Made* A great number of Miocene genera, and even Palaeogeography, global climate some species, are cited or described from both Europe and Africa and/or the Indian Subconti- nent. In other cases, an ancestor-descendant re- After MN 3, Europe formed one continent with lationship has been demonstrated. For most of Asia. This land mass extended from Europe, the Miocene, there seem to have been intensive through north Asia to China and SE Asia and is faunal relationships between Europe, Africa and here referred to as Eurasia. This term does not the Indian Subcontinent. This situation may seem include here SE Europe. At this time, the Brea normal to uso It is, however, noto north of Crete was land and SE Europe and During much of the Tertiary, Africa and India Anatolia formed a continuous landmass. The Para- were isolated continents. There were some peri- tethys was large and extended from the valley of ods when faunal exchange with the northern the Rhone to the Black Sea, Caspian Sea and continents occurred, but these periods seem to further to the east. The Tethys was connected have been widely spaced in time. During a larga with the Indian Ocean and large part of the Middle part of the Oligocene and during the earliest East was a shallow sea. During the earliest Mio- Miocene, Africa and India had been isolated. En- cene, Africa and Arabia formed one continent that demic faunas evolved on these continents. Fam- had been separated from Eurasia and India for a ilies that went extinct in the northern continents considerable time.
    [Show full text]
  • The Plate Tectonics of Cenozoic SE Asia and the Distribution of Land and Sea
    Cenozoic plate tectonics of SE Asia 99 The plate tectonics of Cenozoic SE Asia and the distribution of land and sea Robert Hall SE Asia Research Group, Department of Geology, Royal Holloway University of London, Egham, Surrey TW20 0EX, UK Email: robert*hall@gl*rhbnc*ac*uk Key words: SE Asia, SW Pacific, plate tectonics, Cenozoic Abstract Introduction A plate tectonic model for the development of SE Asia and For the geologist, SE Asia is one of the most the SW Pacific during the Cenozoic is based on palaeomag- intriguing areas of the Earth$ The mountains of netic data, spreading histories of marginal basins deduced the Alpine-Himalayan belt turn southwards into from ocean floor magnetic anomalies, and interpretation of geological data from the region There are three important Indochina and terminate in a region of continen- periods in regional development: at about 45 Ma, 25 Ma and tal archipelagos, island arcs and small ocean ba- 5 Ma At these times plate boundaries and motions changed, sins$ To the south, west and east the region is probably as a result of major collision events surrounded by island arcs where lithosphere of In the Eocene the collision of India with Asia caused an the Indian and Pacific oceans is being influx of Gondwana plants and animals into Asia Mountain building resulting from the collision led to major changes in subducted at high rates, accompanied by in- habitats, climate, and drainage systems, and promoted dis- tense seismicity and spectacular volcanic activ- persal from Gondwana via India into SE Asia as well
    [Show full text]
  • Lhasa Terrane in Southern Tibet Came from Australia
    Lhasa terrane in southern Tibet came from Australia Di-Cheng Zhu1*, Zhi-Dan Zhao1, Yaoling Niu1,2,3, Yildirim Dilek4, and Xuan-Xue Mo1 1State Key Laboratory of Geological Processes and Mineral Resources, and School of Earth Science and Resources, China University of Geosciences, Beijing 100083, China 2School of Earth Sciences, Lanzhou University, Lanzhou 730000, China 3Department of Earth Sciences, Durham University, Durham DH1 3LE, UK 4Department of Geology, Miami University, Oxford, Ohio 45056, USA ABSTRACT REGIONAL GEOLOGY AND DETRITAL The U-Pb age and Hf isotope data on detrital zircons from Paleozoic metasedimentary rocks ZIRCON ANALYSES ε in the Lhasa terrane (Tibet) defi ne a distinctive age population of ca. 1170 Ma with Hf(t) values The Lhasa terrane is one of the three large identical to the coeval detrital zircons from Western Australia, but those from the western east-west−trending tectonic belts in the Tibetan Qiangtang and Tethyan Himalaya terranes defi ne an age population of ca. 950 Ma with a similar Plateau. It is located between the Qiangtang ε Hf(t) range. The ca. 1170 Ma detrital zircons in the Lhasa terrane were most likely derived from and Tethyan Himalayan terranes, bounded by the Albany-Fraser belt in southwest Australia, whereas the ca. 950 Ma detrital zircons from both the Bangong-Nujiang suture zone to the north the western Qiangtang and Tethyan Himalaya terranes might have been sourced from the High and the Indus–Yarlung Zangbo suture zone to Himalaya to the south. Such detrital zircon connections enable us to propose that the Lhasa the south, respectively (Fig.
    [Show full text]
  • Shipping from the Indian Subcontinent to East Coast South America? There Are Rate Changes Coming Into Effect
    6/24/2021 Hapag-Lloyd View in browser Shipping from the Indian Subcontinent to East Coast South America? There are rate changes coming into effect Dear Customer, There is no easy way of saying this: our rates from the Indian Subcontinent to East Coast South America will be increasing with an effective date July 1, 2021. Please find below the details for this rate change: Container types: applies to all container types Rate increase per container: USD 450 For your reference, the geographical scope of these changes is listed as follows: Indian Subcontinent: Bangladesh, India, Sri Lanka, and Maldives East Coast South America: Argentina and Brazil If you require more information related to the above rate changes, please refer to the tariff section of the Hapag-Lloyd website. As an alternative, please contact our customer service team at your location who will be happy to guide you based on your individual situation. If you have any questions or comments, please contact your local Hapag- Lloyd office. Best regards, Valentina from our Customer Communication team https://pages.hapag-lloyd.com/index.php/email/emailWebview?md_id=13640 1/2 6/24/2021 Hapag-Lloyd Sharing is caring Love to get Hapag-Lloyd updates delivered right to your mailbox? Share our newsletter with your colleagues – so no one misses any updates! Share Your Insights Quick Quotes: Boost your business - fast and easy Use our real-time online quotation tool Quick Quotes and boost your business. It’s fast, easy and available anytime, anywhere. Get your quick quote now Learn more Keep in touch IMPRINT PRIVACY TERMS WEBSITE EMAIL PREFERENCES UNSUBSCRIBE © Hapag-Lloyd AG https://pages.hapag-lloyd.com/index.php/email/emailWebview?md_id=13640 2/2.
    [Show full text]
  • Original Pdf Version
    Rhiana Elizabeth Henry Tectonic History Hildebrand Project 1A December 9th, 2016 North America subducted under Rubia Are there modern analogs for Hildebrand’s model of North America subducting under Rubia? In the Geological Society of America Special Papers “Did Westward Subduction Cause Cretaceous–Tertiary Orogeny in the North American Cordillera?” and “Mesozoic Assembly of the North American Cordillera” by Robert S. Hildebrand, the author argues that the North American continent experienced westward subduction under what he calls a “ribbon continent” known as Rubia around ~124Ma. This ribbon continent is composed of multiple terranes both known to be exotic to North America, and terranes that were previously thought to be part of North America. As the seaway between Rubia and North America closed, Hildebrand postulates that North America was dragged underneath with the oceanic crust. This continental material combined with the fluids from the margin caused great amounts of magmatism in the North American Cordillera. Eventually the continental crust broke due to upward buoyancy. This caused slab failure around 75-60 Ma, followed by a reversal of subduction polarity around 53 Ma, with eastward subduction through the mid- Tertiary (Fig. 1). As a way of checking to see if this hypothesis is plausible, I investigated modern geologic settings that are undergoing similar tectonic events. Although these regions are Figure 1: Hildebrand’s model of subduction of not perfect analogies, they share enough North America and Rubia. From Hildebrand, 2009. 1 Rhiana Elizabeth Henry Tectonic History Hildebrand Project 1A December 9th, 2016 tectonic features that Hildebrand’s model appears somewhat less outlandish.
    [Show full text]