DOCSLIB.ORG

Structural History of Ophiolite Obduction, Bay of Islands, Newfoundland

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Structural History of Ophiolite Obduction, Bay of Islands, Newfoundland Structural history of ophiolite obduction, Bay of Islands, Newfoundland GÜNTER SUHR* 1 Centre for Earth Resources Research, Department of Earth Sciences, Memorial University, St. John's, PETER A. CAWOOD J Newfoundland, Canada, A1B 3X5 ABSTRACT INTRODUCTION tachment-related rock units in the Bay of Islands ophiolite complex (BOIC), west Obduction-related structures in the ophi- The mantle section of ophiolites preserves Newfoundland. Along-strike variation in ob- olitic Bay of Islands Complex, west Newfound- the record of two different tectonic events duction-related structures allows definition of land, are classified into shearing dominated (Nicolas and others, 1980). The entire mantle two different obduction styles within the and accretion dominated. Mapping of these section was affected by mantle flow occurring ophiolite: shearing dominated and accretion structures is combined with other geological during the extensional phase of an oceanic dominated. We correlate the different obduc- constraints and provides the basis for a recon- spreading center. These spreading-related tion styles with a new palinspastic restoration struction of the obduction history of the ophi- mantle structures are overprinted along the of the BOIC (Suhr, 1992) and discuss Theo- olite. The earliest detachment structures are base of the ophiolite by strain related to the logical controls which may have determined shearing dominated and are preserved in the obduction of the ophiolite. Spreading-related the nature of obduction structures developed basal peridotites. They indicate north-directed structures are of a low-stress, high-tempera- in the BOIC. thrusting. Detachment was facilitated by the ture nature, strain is distributed homogene- shallow position of the lithosphere-astheno- ously, and mineral shape fabrics are generally REGIONAL SETTING sphere boundary below the recently extinct Bay inconspicuous. Strong olivine lattice fabrics, of Islands spreading ridge. Detachment in- however, indicate large accumulated strain The BOIC represents the highest structural volved lithosphere of the southern side and im- (Ceuleneer and others, 1988). The basal parts slice within the Humber Arm allochthon of mediate northern side of the ridge. During the of the peridotites are characterized by a high- western Newfoundland (Fig. 1). The ophi- early stages of detachment, the Coastal Com- stress, lower temperature microstructure, a olitic St. Anthony Complex in the Hare Bay plex, an arc-related unit located to the west of strong mineral shape fabric, and a heteroge- allochthon (Williams, 1975) in northwest the Bay of Islands Complex, acted largely as a neous structural make-up involving strain lo- Newfoundland occupies a similar structural lateral ramp to obduction. Early accretion oc- calization. The basal peridotites contain the position. Formation of these ophiolite com- curred in two tectonic situations: (1) at the stage earliest information about the process by plexes and their emplacement onto the an- when the basal décollement plane intersected which dense oceanic lithosphere was de- cient continental margin of eastern North the boundary to the structurally and litholog- tached from its original oceanic substrate and America took place during the Early to Mid- ically diverse Coastal Complex; this resulted in was emplaced onto buoyant continental dle Ordovician Taconian Orogeny (Church accretion of blocks up to several hundred crust. The abundance of mantle peridotites in and Stevens, 1971; Williams and Stevens, meters thick with a lithological make-up not ophiolites constrains the level of décollement 1974; Cawood and others, 1988). The BOIC is known from the Bay of Islands Complex; and to within the upper mantle. exposed in four massifs: Table Mountain, (2) at the stage when the basal thrust plane Accreted to the base of the mantle section North Arm Mountain, Blow Me Down intersected the oceanic crust. Deformation in many ophiolites is the metamorphic sole Mountain, and Lewis Hills. To the west of the switched into the mafic and hydrated footwall (Fig. 1). The sole represents a sequence of BOIC is the Little Port Complex, an assem- lithologies and led to intermittent accretion of oceanic crustal lithologies which shows a blage of volcanic and plutonic rocks showing mafic oceanic crustal rocks now preserved in complex inverted metamorphic zonation a variety of metamorphic grades and struc- the metamorphic sole. Only the Lewis Hills from amphibolite- and granulite-facies rocks tural styles (Comeau, 1972; Williams, 1973; massif, located close to the Coastal Complex at the top to subgreenschist facies at the base Karson and Dewey, 1978;Karson, 1984). The during detachment, preserves evidence for (Williams and Smyth, 1973; Malpas, 1979a; Little Port Complex is restricted to outcrops both types of early accretion. At a later stage of Jamieson, 1980, 1981, 1986; Spray and Wil- west of Table Mountain, North Arm Moun- obduction, localized removal of the basal se- liams, 1980; Spray, 1984, 1988; Ghent and tain, and Blow Me Down Mountain (Wil- quence of the ophiolite was associated with ac- Stout, 1981; Searle and Malpas, 1982; liams, 1973). Karson and Dewey (1978) and cretion of a diverse assemblage of harzburgites, McCaig, 1983). The metamorphic sole con- Karson (1984) extended the definition of the amphibolites, and greenschists. tains information about that stage of the ob- Little Port Complex to include the western duction history when the ophiolite was thrust Lewis Hills and proposed the name "Coastal over oceanic crust. Complex" (CC) for this new assemblage. Ac- In this paper, we present new data from the cording to their interpretation, the original *Present address: Department of Mineralogy, oceanic contact between the BOIC and the University of Köln, Zülpicher Str. 49,5000 Köln 1, basal peridotites, the metamorphic sole, and Germany. related lithologies, based on mapping of de- CC is preserved in the Lewis Hills. Geological Society of America Bulletin, v. 105, p. 399-410, 7 figs., March 1993. 399 Downloaded from http://pubs.geoscienceworld.org/gsa/gsabulletin/article-pdf/105/3/399/3381730/i0016-7606-105-3-399.pdf by guest on 03 October 2021 SUHR AND CA WOOD 15 KILOMETRES Lookout Hills Table v Mountain ^ Fig. 5 North Arm Figure 1. Geologic map showing the distribution of the Bay of Islands Mountain Complex, the Coastal Complex, and rock units accreted during detach- ment. Dashed boxes indicate the location of maps shown in Figures 2,4, and 5. Blow Me Down Mountain Fig. 2 Lewis Hills Fig. 4 58°00'W Bay of Islands Coastal rocks accreted Complex Complex during detachment Based largely on structural evidence, the recent geochemical data rule out such a model 1973; Malpas and others, 1973; Malpas, CC was interpreted as a fracture zone assem- (Jenner and others, 1992; Elthon, 1992). In a 1979b; Searle and Stevens, 1984; Jenner and blage adjacent to which the BOIC formed different interpretation, based mainly on others, 1992). along an oceanic spreading center (Karson lithological, geochemical, and age con- Our work is limited to the BOIC where a and Dewey, 1978; Karson, 1984). Geochem- straints, the Little Port Complex (that is, the metamorphic sole forms a continuous sheet ical evidence was later used to suggest a clas- CC excluding the western Lewis Hills) has on the eastern flank of all four massifs (Fig. 1; sic mid-ocean-ridge environment for this con- been assigned to formation of an island arc, Williams, 1973; Williams and Smyth, 1973; figuration (Casey and others, 1985), but distinct from the BOIC (Williams and Payne, Malpas, 1979a; McCaig, 1983). Late folding 400 Geological Society of America Bulletin, March 1993 Downloaded from http://pubs.geoscienceworld.org/gsa/gsabulletin/article-pdf/105/3/399/3381730/i0016-7606-105-3-399.pdf by guest on 03 October 2021 OPHIOLITE OBDUCTION, BAY OF ISLANDS, NEWFOUNDLAND the allochthon onto the North American mar- gin. This later emplacement phase of the ob- duction process is marked by the widespread development of mélange (Stevens, 1970; Wil- liams and Stevens, 1974; Williams, 1975). Shearing-Dominated Structures Shearing-dominated structures are best de- veloped within the northern and central Blow Me Down Mountain where a gradual over- print of the spreading-related structures by detachment structures occurs 300-500 m above the base of the mantle sequence (Fig. 2). This estimate contrasts with the map- ping of Savie (1988), who considers only the basal 50-170 m to be affected by detachment- related strain. Foliations in the detachment domain dip to the northwest, parallel to those in the spreading domain. Mineral-stretching lineations change, however, from northwest plunging in the spreading-related structures (mean 34° to 324°) to gently north plunging in the detachment structures (Fig. 3a; compare with Girardeau and Nicolas, 1981). Judging from a progressively stronger mineral shape fabric, the detachment-related strain in- creases gradually toward the base of the pe- ridotites and culminates in ultramafic ul- tramylonites, as much as 20 m thick, located immediately above the metamorphic sole. The ultramylonites are, however, not later- ally continuous. Shear-sense determinations of the peridotites were performed using a well-established microstructure method based on the obliquity between the lattice fab- ric of olivine grains and the shape fabric de- Figure 2. Simplified map of detachment-related structures in the eastern part of Blow Me Down fined by spinel (Nicolas and others, 1972; Mountain. Ceuleneer
Load more

Recommended publications
  • Ophiolite in Southeast Asia
    Ophiolite in Southeast Asia CHARLES S. HUTCHISON Department of Geology, University of Malaya, Kuala Lumpur, Malaysia ABSTRACT semblages are classified into definite ophiolite, tentatively identified ophiolite, and associations that have previously been named No fewer than 20 belts of mafic-ultramafic assemblages have ophiolite but that are not. Each of the ophiolite or other been named "ophiolite" in the complex Southeast Asia region of mafic-ultramafic associations is listed in Table 1, with brief reasons Sundaland. Fewer than half of these can be confidently classified as for its classification, particularly in regard to the petrography of the ophiolite. The only well-documented complete ophiolite, with con- rock suite and the nature of its sedimentary envelope. The basis for tinuous conformable sections from mantle harzburgite through identification (or rejection) of these rock associations as ophiolite is gabbro to spilite, occurs in northeast Borneo and the neighboring discussed in the following section. Philippine Islands. It contains a record of oceanic lithospheric his- tory from Jurassic to Tertiary and has a Miocene emplacement age. OPHIOLITE FORMATION All other ophiolite belts of the region are either incomplete or dis- membered. The Sundaland region probably has examples of several The oceanic lithosphere, with its thin oceanic crust formed along types of emplacement mechanism and emplacement ages ranging the spreading axes of divergent plate junctures, is thought to be from early Paleozoic to Cenozoic. Key words: Sundaland, plate consumed at arc-trench systems of convergent plate junctures (Fig. tectonics. 2). Minor subtractions of crustal and mantle material from de- scending slabs of oceanic lithosphere are thought to be added to INTRODUCTION belts of mélange, and imbricate slices are caught in crustal subduc- tion zones at the trenches (Dickinson, 1972).
    [Show full text]
  • Hydrothermal Alteration of a Supra-Subduction Zone Ophiolite Analog, Tonga
    AN ABSTRACT OF THE THESIS OF Melanie C. Kelman for the degree of Master of Science in Geology presented on May 29, 1998. Title: Hydrothermal Alteration of a Supra-Subduction Zone Ophiolite Analog, Tonga. Southwest Pacific. Abstract approved: Redacted for Privacy Sherman Bloomer The basement of the Tonga intraoceanic forearc comprises Eocene arc volcanic crust formed during the earliest phases of subduction. Volcanic rocks recovered from the forearc include boninites and arc tholeiites, apparently erupted into and upon older mid- oceanic ridge tholeiites. Rock assemblages suggest that the forearc basement is a likely analog for large supra-subduction zone (SSZ) ophiolites not only in structure and Ethology, but also in the style of hydrothermal alteration. Dredged volcanic samples from the central Tonga forearc (20-24° S) exhibit the effects of seafloor weathering, low (<200°C, principally <100°C) alteration, and high temperature (>200°C) alteration. Tholeiites and arc tholeiites are significantly more altered than boninites. Seafloor weathering is due to extensive interaction with cold oxidizing seawater, and is characterized by red-brown staining and the presence of Fe- oxyhydroxides. Low temperature alteration is due to circulation of evolving seawater- derived fluids through the volcanic section until fluid pathways were closed by secondary mineral precipitation. Low temperature alteration is characterized by smectites, celadonite, phillipsite, mixed-layer smectite/chlorite, carbonates, and silica. All phases fill veins and cavities; clay minerals and silica also replace the mesostasis and groundmass phases. Low temperature alteration enriches the bulk rock in K, Ba, and Na, and mobilizes other elements to varying extents. The few high temperature samples are characterized by mobilizes other elements to varying extents.
    [Show full text]
  • Pan-African Orogeny 1
    Encyclopedia 0f Geology (2004), vol. 1, Elsevier, Amsterdam AFRICA/Pan-African Orogeny 1 Contents Pan-African Orogeny North African Phanerozoic Rift Valley Within the Pan-African domains, two broad types of Pan-African Orogeny orogenic or mobile belts can be distinguished. One type consists predominantly of Neoproterozoic supracrustal and magmatic assemblages, many of juvenile (mantle- A Kröner, Universität Mainz, Mainz, Germany R J Stern, University of Texas-Dallas, Richardson derived) origin, with structural and metamorphic his- TX, USA tories that are similar to those in Phanerozoic collision and accretion belts. These belts expose upper to middle O 2005, Elsevier Ltd. All Rights Reserved. crustal levels and contain diagnostic features such as ophiolites, subduction- or collision-related granitoids, lntroduction island-arc or passive continental margin assemblages as well as exotic terranes that permit reconstruction of The term 'Pan-African' was coined by WQ Kennedy in their evolution in Phanerozoic-style plate tectonic scen- 1964 on the basis of an assessment of available Rb-Sr arios. Such belts include the Arabian-Nubian shield of and K-Ar ages in Africa. The Pan-African was inter- Arabia and north-east Africa (Figure 2), the Damara- preted as a tectono-thermal event, some 500 Ma ago, Kaoko-Gariep Belt and Lufilian Arc of south-central during which a number of mobile belts formed, sur- and south-western Africa, the West Congo Belt of rounding older cratons. The concept was then extended Angola and Congo Republic, the Trans-Sahara Belt of to the Gondwana continents (Figure 1) although West Africa, and the Rokelide and Mauretanian belts regional names were proposed such as Brasiliano along the western Part of the West African Craton for South America, Adelaidean for Australia, and (Figure 1).
    [Show full text]
  • New Perspectives on Tasmanian Geology
    TASMANIA - ANISLANDOFPOmNIIAL New perspectives on Tasmanian geology C. MeA. POWELL Geology Departrrumt, The University ofWe stem Australia. ABSTRACT New infonnation about the structure and sedimentary basin cotljiguration in the southern TastnIJII Fold Bell cotljirms thiltthe eastern TasmLlllia terrane is the on-strike COlllinuation o/the Melbourne Zone o/VictoriIL It represents a passive-margin to back-arc basin which was deformed and amalgamated with the western TasmLlllia terrane in the late Middle Devonian. The western TastnlJlliaterrane hils chilracteristics 0/ both the western lAchlan Fold Bell and the Kanmantao Fold Bell, and could be a largely exotic block lying across the jutlCtion between the tw%ld bells. The Precambrian "basemelll" o/TQStnIJ1Iia, regarded/or so long asfirmly rooted to its mafIlle lithosphere, could be composed o/thrust-bounded slices accreted to the TQStnIJ1I Fold Bell initially in the Middle Cambrian during westward thrusting o/the KanmafIloo Fold Belt over the platform margin in the Adelaide region. Renewed contraction in the Middle Devonian/ormed tnIJIIy o/the preselllthrust contacts. These new ideas make it imperative that existing esploration philosophies and nwdels are re-exmnined 10 take ill/o accoulllthe thrust-/aull geometry and the possible allochthonous nature o/much o/TasmLlllia. INTRODUCTION local areas of contractional deformation (powell, 1983, 1984a). The whole eastern Lachlan Fold Belt appears to have been a zone of transcurrence with local areas of transtension Tasmania occupies an imponant place in the geological and transpression. Theeasternand western] acblanFoldBelt framework of AuslIalia, lying at the southern extension of were reunited in the Middle Devonian when contractional the 1000-km wide Tasman Fold Belt, which occupies the deformation affected both parts, and the region rose above eastern third of the continent (fig.
    [Show full text]
  • Deepwater Fold-And-Thrust Belt Along New Caledonia's Western Margin
    Deepwater fold-and-thrust belt along New Caledonia’s western margin: relation to post-obduction vertical motions J. Collot, M. Patriat, S. Etienne, P. Rouillard, F. Soetaert, C Juan, B. Marcaillou, Giulia Palazzin, Camille Clerc, P. Maurizot, et al. To cite this version: J. Collot, M. Patriat, S. Etienne, P. Rouillard, F. Soetaert, et al.. Deepwater fold-and-thrust belt along New Caledonia’s western margin: relation to post-obduction vertical motions. Tectonics, American Geophysical Union (AGU), 2017, 36, pp.2108-2122. 10.1002/2017TC004542. insu-01614136 HAL Id: insu-01614136 https://hal-insu.archives-ouvertes.fr/insu-01614136 Submitted on 24 Oct 2017 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. PUBLICATIONS Tectonics RESEARCH ARTICLE Deepwater Fold-and-Thrust Belt Along New 10.1002/2017TC004542 Caledonia’s Western Margin: Relation Key Points: to Post-obduction Vertical Motions • New deepwater fold-and-thrust belt discovered off New Caledonia’s J. Collot1 , M. Patriat1,2 , S. Etienne1,3 , P. Rouillard1,3,4, F. Soetaert1,2, C. Juan1, western margin 5 6 7 1 1,3 1,3 1 • Origin of the deepwater B. Marcaillou , G. Palazzin , C.
    [Show full text]
  • Thermo-Mechanical Modeling of the Obduction Process Based on The
    Thermo-mechanical modeling of the obduction process based on the Oman ophiolite case Thibault Duretz, Philippe Agard, Philippe Yamato, Céline Ducassou, Evgenii Burov, T. V. Gerya To cite this version: Thibault Duretz, Philippe Agard, Philippe Yamato, Céline Ducassou, Evgenii Burov, et al.. Thermo- mechanical modeling of the obduction process based on the Oman ophiolite case. Gondwana Research, Elsevier, 2016, 32, pp.1-10. 10.1016/j.gr.2015.02.002. insu-01120232 HAL Id: insu-01120232 https://hal-insu.archives-ouvertes.fr/insu-01120232 Submitted on 9 Mar 2015 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. ACCEPTED MANUSCRIPT Thermo-mechanical modeling of the obduction process based on the Oman ophiolite case Thibault Duretz1,2, Philippe Agard2, Philippe Yamato3, Céline Ducassou4, Evguenii B. Burov2, Taras V. Gerya5 1Institut des sciences de la Terre, University of Lausanne, 1015 Lausanne, Switzerland 2ISTEP, UMR CNRS 7193, UPMC Sorbonne Universités, 75252 Cedex 05, Paris, France 3Geosciences Rennes, UMR CNRS 6118, Université de Rennes 1, 35042 Rennes Cedex, France 4Applied Geosciences, GUtech, PO Box 1816, Athaibah, PC 130, Sultanate of Oman 5Institute of Geophysics, ETH Zürich, Sonneggstrasse 5, 8092 Zürich, Switzerland submission to – Gondwana Research Keywords: Obduction; Oman; numerical modeling ACCEPTED MANUSCRIPT ACCEPTED MANUSCRIPT Abstract Obduction emplaces regional-scale fragments of oceanic lithosphere (ophiolites) over continental lithosphere margins of much lower density.
    [Show full text]
  • Zagros Orogeny
    Zagros orogeny: a subduction-dominated process Philippe Agard, Jafar Omrani, Laurent Jolivet, Hubert Whitechurch, Bruno Vrielynck, Wim Spakman, Patrick Monié, Bertrand Meyer, R. Wortel To cite this version: Philippe Agard, Jafar Omrani, Laurent Jolivet, Hubert Whitechurch, Bruno Vrielynck, et al.. Zagros orogeny: a subduction-dominated process. Geological Magazine, Cambridge University Press (CUP), 2011, 148 (5-6), pp.692-725. 10.1017/S001675681100046X. insu-00616582 HAL Id: insu-00616582 https://hal-insu.archives-ouvertes.fr/insu-00616582 Submitted on 4 Feb 2013 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. Geol. Mag. 148 (5–6), 2011, pp. 692–725. c Cambridge University Press 2011 692 doi:10.1017/S001675681100046X Zagros orogeny: a subduction-dominated process P. AGARD∗†, J. OMRANI‡, L. JOLIVET§, H. WHITECHURCH¶, B. VRIELYNCK∗, W. SPAKMAN,P.MONIÉ#,B.MEYER∗ &R. WORTEL ∗ISTEP, UMR 7193, Université Pierre et Marie Curie – Université Paris 6, 4 pl. Jussieu, Paris 75005, France ‡Geological Survey of Iran, Tehran, Iran §ISTO, Université d’Orléans, France ¶EOST, Strasbourg, France Geosciences, Utrecht University, The Netherlands #Géosciences Montpellier, UMR 5573, Université Montpellier 2, France (Received 17 January 2011; accepted 3 May 2011; first published online 5 July 2011) Abstract – This paper presents a synthetic view of the geodynamic evolution of the Zagros orogen within the frame of the Arabia–Eurasia collision.
    [Show full text]
  • The Callovian Unconformity and the Ophiolite Obduction Onto the Pelagonian Carbonate Platform of the Internal Hellenides
    Δελτίο της Ελληνικής Γεωλογικής Εταιρίας, τόμος L, σελ. 144-152 Bulletin of the Geological Society of Greece, vol. L, p. 144-152 Πρακτικά 14ου Διεθνούς Συνεδρίου, Θεσσαλονίκη, Μάιος 2016 Proceedings of the 14th International Congress, Thessaloniki, May 2016 THE CALLOVIAN UNCONFORMITY AND THE OPHIOLITE OBDUCTION ONTO THE PELAGONIAN CARBONATE PLATFORM OF THE INTERNAL HELLENIDES Scherreiks R.1, Meléndez G.2, Bouldagher-Fadel M.3, Fermeli G.4 and Bosence D.5 1Bayerische Staaatssammlung, Department of Geology, University of Munich, Luisenstr. 33, 80333 Munich, Germany, [email protected] 2Departamento de Geologia (Paleontologia), Universidad de Zaragoza, 50009 Saragossa, Spain, [email protected] 3Earth Sciences, University College London, Gower Street, London WC1E6BT, UK, [email protected] 4Department of Historical Geology and Paleontology, University of Athens, Panepistimioupolis, Zographou, 15784 Athens, Greece, [email protected] 5Department of Earth Sciences, Royal Holloway University of London, Egham TW20 0EX, UK, [email protected] Abstract The carbonate-platform-complex and the oceanic formations of the central Pelagonian zone of the Hellenides evolved in response to a sequence of plate-tectonic episodes of ocean spreading, plate convergence and ophiolite obduction. The bio- stratigraphies of the carbonate platform and the oceanic successions, show that the Triassic-Early Jurassic platform was coeval with an ocean where pillow basalts and radiolarian cherts were being deposited. After convergence began during late Early- Jurassic - Middle Jurassic time, the oceanic leading edge of the Pelagonian plate was subducted beneath the leading edge of the oceanic, overriding plate. The platform subsided while a supra-subduction, volcanic-island-arc evolved.
    [Show full text]
  • Zeolites in Tasmania
    Mineral Resources Tasmania Tasmanian Geological Survey Record 1997/07 Tasmania Zeolites in Tasmania by R. S. Bottrill and J. L. Everard CONTENTS INTRODUCTION ……………………………………………………………………… 2 USES …………………………………………………………………………………… 2 ECONOMIC SIGNIFICANCE …………………………………………………………… 2 GEOLOGICAL OCCURRENCES ………………………………………………………… 2 TASMANIAN OCCURRENCES ………………………………………………………… 4 Devonian ………………………………………………………………………… 4 Permo-Triassic …………………………………………………………………… 4 Jurassic …………………………………………………………………………… 4 Cretaceous ………………………………………………………………………… 5 Tertiary …………………………………………………………………………… 5 EXPLORATION FOR ZEOLITES IN TASMANIA ………………………………………… 6 RESOURCE POTENTIAL ……………………………………………………………… 6 MINERAL OCCURRENCES …………………………………………………………… 7 Analcime (Analcite) NaAlSi2O6.H2O ……………………………………………… 7 Chabazite (Ca,Na2,K2)Al2Si4O12.6H2O …………………………………………… 7 Clinoptilolite (Ca,Na2,K2)2-3Al5Si13O36.12H2O ……………………………………… 7 Gismondine Ca2Al4Si4O16.9H2O …………………………………………………… 7 Gmelinite (Na2Ca)Al2Si4O12.6H2O7 ……………………………………………… 7 Gonnardite Na2CaAl5Si5O20.6H2O ………………………………………………… 10 Herschelite (Na,Ca,K)Al2Si4O12.6H2O……………………………………………… 10 Heulandite (Ca,Na2,K2)2-3Al5Si13O36.12H2O ……………………………………… 10 Laumontite CaAl2Si4O12.4H2O …………………………………………………… 10 Levyne (Ca2.5,Na)Al6Si12O36.6H2O ………………………………………………… 10 Mesolite Na2Ca2(Al6Si9O30).8H2O ………………………………………………… 10 Mordenite K2.8Na1.5Ca2(Al9Si39O96).29H2O ………………………………………… 10 Natrolite Na2(Al2Si3O10).2H2O …………………………………………………… 10 Phillipsite (Ca,Na,K)3Al3Si5O16.6H2O ……………………………………………… 11 Scolecite CaAl2Si3O10.3H20 ………………………………………………………
    [Show full text]
  • Zagros Fold Belt: Orogenic Accretion from Obduction to Collision
    Geophysical Research Abstracts Vol. 16, EGU2014-5690, 2014 EGU General Assembly 2014 © Author(s) 2014. CC Attribution 3.0 License. Zagros fold belt: orogenic accretion from obduction to collision Jaume Vergés, Eduard Saura, Emilio Casciello, Manel Fernandez, Daniel Garcia-Castellanos, Ivone Jiménez-Munt, Montserrat Torne, and Antonio Villaseñor Group of Dynamics of the Lithosphere (GDL), Institute of Earth Sciences Jaume Almera, ICTJA-CSIC, Lluís Solé i Sabarís s/n, 08028 Barcelona, Spain ([email protected]) The Zagros orogenic system comprises an exceptionally wide deformation zone between Arabia and Eurasia, embracing the entire Iran, and resulting from the closure of the Neotethys Ocean through its protracted NE-dipping subduction beneath Eurasia. The ∼2000-km long, NW-SE trending Zagros fold belt is at the front of this orogenic system formed by the Sanandaj–Sirjan Zone and the Urumieh–Dokhtar Magmatic Arc, which are parallel to the main tectonic grain and have different geodynamic significance. The Zagros fold belt deforms 10-12-km thick Arabian sedimentary cover, which records compressive deformation since Late Cretaceous times. These tectonic events and their sequence have been studied in greater detail in the last ten years, mainly due to the profusion of dating of the syntectonic marine and non-marine sediments in the foreland basin. Despite these new data, and taking in account that there is a general consensus that the Zagros orogeny occurred during the complete consumption of the Neotethys Ocean, tectonic interpretations differ and ages of major geodynamic events remain controversial. Our studies confirm that the early Amiran foreland basin depocenter migrated from Campanian to Eocene (c.
    [Show full text]
  • Synchronous Formation of the Metamorphic
    Earth and Planetary Science Letters 451 (2016) 185–195 Contents lists available at ScienceDirect Earth and Planetary Science Letters www.elsevier.com/locate/epsl Synchronous formation of the metamorphic sole and igneous crust of the Semail ophiolite: New constraints on the tectonic evolution during ophiolite formation from high-precision U–Pb zircon geochronology ∗ Matthew Rioux a, , Joshua Garber a,b, Ann Bauer c, Samuel Bowring c, Michael Searle d, Peter Kelemen e, Bradley Hacker a,b a Earth Research Institute, University of California, Santa Barbara, CA 93106, USA b Department of Earth Science, University of California, Santa Barbara, CA 93106, USA c Department of Earth, Atmospheric and Planetary Science, Massachusetts Institute of Technology, Cambridge, MA 02139, USA d Department of Earth Sciences, University of Oxford, Oxford, OX1 3AN, UK e Department of Earth and Environmental Studies, Columbia University, Lamont Doherty Earth Observatory, Palisades, NY 10964, USA a r t i c l e i n f o a b s t r a c t Article history: The Semail (Oman–United Arab Emirates) and other Tethyan-type ophiolites are underlain by a Received 11 April 2016 sole consisting of greenschist- to granulite-facies metamorphic rocks. As preserved remnants of the Received in revised form 2 June 2016 underthrust plate, sole exposures can be used to better understand the formation and obduction Accepted 25 June 2016 of ophiolites. Early models envisioned that the metamorphic sole of the Semail ophiolite formed Available online 29 July 2016 as a result of thrusting of the hot ophiolite lithosphere over adjacent oceanic crust during initial Editor: M.
    [Show full text]
  • Zhigang Han Title of Thesis: Correlations
    University of Alberta Library Release Form Name of Author: Zhigang Han Title of Thesis: Correlations between seismic and magnetic susceptibility anisotropy in serpentinized peridotite Degree: Master of Science in Geophysics Year this Degree Granted: 2004 Permission is hereby granted to the University of Alberta Library to reproduce single copies of this thesis and to lend or sell such copies for private, scholarly or scientific research purposes only. The author reserves all other publication and other rights in association with the copy- right in the thesis, and except as herein before provided, neither the thesis nor any sub- stantial portion thereof may be printed or otherwise reproduced in any material form whatever without the author’s prior written permission. Zhigang Han 602 Avadh Bhatia Physics Building University of Alberta Edmonton, Alberta Canada, T6G 2J1 [email protected] Date: University of Alberta CORRELATIONS BETWEEN SEISMIC AND MAGNETIC SUSCEPTIBILITY ANISOTROPY IN SERPENTINIZED PERIDOTITE by Zhigang Han A thesis submitted to the Faculty of Graduate Studies and Research in partial fulfillment of the requirements for the degree of Master of Science in Geophysics. Department of Physics Edmonton, Alberta Fall 2004 University of Alberta Faculty of Graduate Studies and Research The undersigned certify that they have read, and recommend to the Faculty of Graduate Studies and Research for acceptance, a thesis entitled Correlations between seismic and magnetic susceptibility anisotropy in serpentinized peridotite submitted by Zhigang Han in partial fulfillment of the requirements for the degree of Master of Science in Geophysics. Dr. D. Schmitt (Co-supervisor) Dr. V. Kravachinsky (Supervisor) Dr. R. Luth (Earth and Atmospheric Sciences) Dr.
    [Show full text]