Tasmania's River Geomorphology: Stream Character and Regional
Total Page:16
File Type:pdf, Size:1020Kb
Load more
Recommended publications
-
Podiform Chromite Deposits—Database and Grade and Tonnage Models
Podiform Chromite Deposits—Database and Grade and Tonnage Models Scientific Investigations Report 2012–5157 U.S. Department of the Interior U.S. Geological Survey COVER View of the abandoned Chrome Concentrating Company mill, opened in 1917, near the No. 5 chromite mine in Del Puerto Canyon, Stanislaus County, California (USGS photograph by Dan Mosier, 1972). Insets show (upper right) specimen of massive chromite ore from the Pillikin mine, El Dorado County, California, and (lower left) specimen showing disseminated layers of chromite in dunite from the No. 5 mine, Stanislaus County, California (USGS photographs by Dan Mosier, 2012). Podiform Chromite Deposits—Database and Grade and Tonnage Models By Dan L. Mosier, Donald A. Singer, Barry C. Moring, and John P. Galloway Scientific Investigations Report 2012-5157 U.S. Department of the Interior U.S. Geological Survey U.S. Department of the Interior KEN SALAZAR, Secretary U.S. Geological Survey Marcia K. McNutt, Director U.S. Geological Survey, Reston, Virginia: 2012 This report and any updates to it are available online at: http://pubs.usgs.gov/sir/2012/5157/ For more information on the USGS—the Federal source for science about the Earth, its natural and living resources, natural hazards, and the environment—visit http://www.usgs.gov or call 1–888–ASK–USGS For an overview of USGS information products, including maps, imagery, and publications, visit http://www.usgs.gov/pubprod To order this and other USGS information products, visit http://store.usgs.gov Suggested citation: Mosier, D.L., Singer, D.A., Moring, B.C., and Galloway, J.P., 2012, Podiform chromite deposits—database and grade and tonnage models: U.S. -
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). -
Bedrock Geology Glossary from the Roadside Geology of Minnesota, Richard W
Minnesota Bedrock Geology Glossary From the Roadside Geology of Minnesota, Richard W. Ojakangas Sedimentary Rock Types in Minnesota Rocks that formed from the consolidation of loose sediment Conglomerate: A coarse-grained sedimentary rock composed of pebbles, cobbles, or boul- ders set in a fine-grained matrix of silt and sand. Dolostone: A sedimentary rock composed of the mineral dolomite, a calcium magnesium car- bonate. Graywacke: A sedimentary rock made primarily of mud and sand, often deposited by turbidi- ty currents. Iron-formation: A thinly bedded sedimentary rock containing more than 15 percent iron. Limestone: A sedimentary rock composed of calcium carbonate. Mudstone: A sedimentary rock composed of mud. Sandstone: A sedimentary rock made primarily of sand. Shale: A deposit of clay, silt, or mud solidified into more or less a solid rock. Siltstone: A sedimentary rock made primarily of sand. Igneous and Volcanic Rock Types in Minnesota Rocks that solidified from cooling of molten magma Basalt: A black or dark grey volcanic rock that consists mainly of microscopic crystals of pla- gioclase feldspar, pyroxene, and perhaps olivine. Diorite: A plutonic igneous rock intermediate in composition between granite and gabbro. Gabbro: A dark igneous rock consisting mainly of plagioclase and pyroxene in crystals large enough to see with a simple magnifier. Gabbro has the same composition as basalt but contains much larger mineral grains because it cooled at depth over a longer period of time. Granite: An igneous rock composed mostly of orthoclase feldspar and quartz in grains large enough to see without using a magnifier. Most granites also contain mica and amphibole Rhyolite: A felsic (light-colored) volcanic rock, the extrusive equivalent of granite. -
The Geology, Petrography and Geochemistry of Gabbroic Rocks Of
The Geology, Petrography and Geochemistry of Gabbroic Rocks of the Pants Lake Intrusive Suite on the Donner/Teck South Voisey's Bay Property, North-Central Labrador, Canada Heather E. MacDonald A thesis submitted in conformity with the requirements for the degree of Mastet's of Science Graduate Department of the Department of Geology University of Toronto O Copyright by Heather E. MacDonald, 1999 National Library Bibliothèque nationale 1*1 of Canada du Canada Acquisitions and Acquisitions et Bibliographie Services services bibliographiques 395 Wellingtori Street 395. rue Wellington OttawaON K1A ON4 OnawaON KlAONQ Canada Canada The author has granted a non- L'auteur a accordé une licence non exclusive licence allowing the exclusive permettant à la National Library of Canada to Bibliothèque nationale du Canada de reproduce, loan, distribute or seii reproduire, prêter, distribuer ou copies of this thesis in microform, vendre des copies de cette thèse sous paper or electronic formats. la forme de rnicrofiche/film, de reproduction sur papier ou sur format électronique. The author retains ownership of the L'auteur consewe la propriété du copyright in this thesis. Neither the droit d'auteur qui protège cette thèse. thesis nor substantiai extracts fiom it Ni la thèse ni des extraits substantiels may be printed or otherwise de celle-ci ne doivent être imprimés reproduced without the author's ou autrement reproduits sans son permission. autorisation. The Geology, Petrography and Ceochernistry of Gabbroic Rocks of the Pants Lake Intrusive Suite on the Donner/Teck South Voisey's Bay Property, North-Central Labrador, Canada Heather E. MacDonald Master's of Science, 1999 Department of Geology University of Toronto Abstract The South Voisey's Bay property held by Donner Minerals Limited in North-Central Labrador hosts Ni-Cu-Co mineralization within gabbroic rocks of the Pants Lake Intrusive Suite (PLIS). -
Mineralogy and Chemistry of Rare Earth Elements in Alkaline Ultramafic Rocks and Fluorite in the Western Kentucky Fluorspar District Warren H
University of Kentucky UKnowledge Kentucky Geological Survey Report of Kentucky Geological Survey Investigations 6-2019 Mineralogy and Chemistry of Rare Earth Elements in Alkaline Ultramafic Rocks and Fluorite in the Western Kentucky Fluorspar District Warren H. Anderson University of Kentucky, [email protected] Right click to open a feedback form in a new tab to let us know how this document benefits oy u. Follow this and additional works at: https://uknowledge.uky.edu/kgs_ri Part of the Geology Commons Repository Citation Anderson, Warren H., "Mineralogy and Chemistry of Rare Earth Elements in Alkaline Ultramafic Rocks and Fluorite in the Western Kentucky Fluorspar District" (2019). Kentucky Geological Survey Report of Investigations. 55. https://uknowledge.uky.edu/kgs_ri/55 This Report is brought to you for free and open access by the Kentucky Geological Survey at UKnowledge. It has been accepted for inclusion in Kentucky Geological Survey Report of Investigations by an authorized administrator of UKnowledge. For more information, please contact [email protected]. Mineralogy and Chemistry of Rare Earth Elements in Alkaline Ultramafic Rocks and Fluorite in the Western Kentucky Fluorspar District Warren H. Anderson Report of Investigations 8 doi.org/10.13023/kgs.ri08.13 Series XIII, 2019 Cover Photo: Various alkaline ultramafic rocks showing porphyritic, brecciated, and aphanitic textures, in contact with host limestone and altered dike texture. From left to right: • Davidson North dike, Davidson core, YH-04, 800 ft depth. Lamprophyre with calcite veins, containing abundant rutile. • Coefield area, Billiton Minner core BMN 3. Intrusive breccia with lamprophyric (al- nöite) matrix. • Maple Lake area, core ML-1, 416 ft depth. -
A K-Feldspar Breccia from the MO-Cu Stockwork Deposit in the Galway Granite, West of Ireland
Journal ofthe Geological Sociefy, London, Vol. 145, 1988, pp. 661-667, 4 figs, 2 tables. Printed in Northern Ireland A K-feldspar breccia from the MO-Cu stockwork deposit in the Galway Granite, west of Ireland J. M. DERHAM & M. FEELY Department of Geology, University College, Galway, Ireland Abstrart: A K-feldspar breccia, spatially associated with the MO-Cu mineralization of a stockwork in the Late Caledonian Galway Granite at Mace Head, is described for the first time. Detailed mapping reveals a network of breccia pods and veins over an area of approximately 6000 m’. The breccia is clast-supportedand is composed of sub-angular fragments of perthiticK-feldspar megacrysts (<10cm), granite and microgranodiorite clasts (<25 m) set in a matrix of quartz (<l cm), biotite (<5 cm) and apatite (<3 mm). Field and textural studies indicated that the feldspar megacrysts and granite clasts were brecciated and silicified as they were carried (to the present structural level) by hydrous K- and Si0,-rich fluids. The residue of these fluids crystallized to form the breccia matrix. The formation of the breccia predates the mineralized quartz veins of the MO-Cu stockwork. It is concluded that the breccia formation is genetically related to ore-forming processes in the Galway Granite. Breccia lithologies with a wide spectrum of characteristics of the batholith. It is composed of concentric arcs of are associated worldwide with molybdenumand other metal K-feldspar-rich and K-feldspar-poor varieties of theCarna concentrations especially in mineralized graniteterrains granodiorite (Fig. 1). (Sham 1978; Norman & Sawkins 1985; Scherkenbach et al. 1985;- Warnaars et al. -
Depleted Spinel Harzburgite Xenoliths in Tertiary Dykes from East Greenland: Restites from High Degree Melting
Earth and Planetary Science Letters 154Ž. 1998 221±235 Depleted spinel harzburgite xenoliths in Tertiary dykes from East Greenland: Restites from high degree melting Stefan Bernstein a,), Peter B. Kelemen b,1, C. Kent Brooks a,c,2 a Danish Lithosphere Centre, éster Voldgade 10, DK-1350 Copenhagen K, Denmark b Woods Hole Oceanographic Institution, Woods Hole, City, MA 02543, USA c Geological Institute, UniÕersity of Copenhagen, éster Voldgade 10, DK-1350 Copenhagen K, Denmark Received 28 April 1997; revised 19 September 1997; accepted 4 October 1997 Abstract A new collection of mantle xenoliths in Tertiary dykes from the Wiedemann Fjord area in Southeast Greenland shows that this part of the central Greenland craton is underlain by highly depleted peridotites. The samples are mostly spinel harzburgites with highly forsteritic olivinesŽ. Fo87± 94 , average Fo 92.7 . This, together with unusually high modal olivine contentsŽ. 70±)95% , places the Wiedemann harzburgites in a unique compositional field. Relative to depleted Kaapvaal harzburgites with comparable Fo in olivine, the Wiedemann samples have considerably lower bulk SiO2 Ž average 42.6 wt% versus 44±49 wt%. Spinel compositions are similar to those in other sub-cratonic harzburgites. Pyroxene equilibrium temperatures average 8508C, which is above an Archaean cratonic geotherm at an inferred pressure of 1±2 GPa, but low enough so that it is unlikely that the xenoliths represent residual peridotites created during Tertiary magmatism. Among mantle samples, the Wiedemann harzburgites are, in terms of their bulk composition, most similar to harzburgites from the ophiolites of Papua New GuineaŽ. PNG and New Caledonia Ž. -
The Diversity of Magmatism at a Convergent Plate
1 Flow of partially molten crust controlling construction, growth and collapse of the Variscan orogenic belt: 2 the geologic record of the French Massif Central 3 4 Vanderhaeghe Olivier1, Laurent Oscar1,2, Gardien Véronique3, Moyen Jean-François4, Gébelin Aude5, Chelle- 5 Michou Cyril2, Couzinié Simon4,6, Villaros Arnaud7,8, Bellanger Mathieu9. 6 1. GET, UPS, CNRS, IRD, 14 avenue E. Belin, F-31400 Toulouse, France 7 2. ETH Zürich, Institute for Geochemistry and Petrology, Clausiusstrasse 25, CH-8038 Zürich, Switzerland 8 3. Université Lyon 1, ENS de Lyon, CNRS, UMR 5276 LGL-TPE, F-69622, Villeurbanne, France 9 4. Université de Lyon, Laboratoire Magmas et Volcans, UJM-UCA-CNRS-IRD, 23 rue Dr. Paul Michelon, 10 42023 Saint Etienne 11 5. School of Geography, Earth and Environmental Sciences, Plymouth University, Plymouth,UK 12 6. CRPG, Université de Lorraine, CNRS, UMR7358, 15 rue Notre Dame des Pauvres, F-54501 13 Vandoeuvre-lès-Nancy, France 14 7. Univ d’Orléans, ISTO, UMR 7327, 45071, Orléans, France ; CNRS, ISTO, UMR 7327, 45071 Orléans, 15 France ; BRGM, ISTO, UMR 7327, BP 36009, 45060 Orléans, France 16 8. University of Stellenbosch, Department of Earth Sciences, 7602 Matieland, South Africa 17 9. TLS Geothermics, 91 chemin de Gabardie 31200 Toulouse. 18 19 [email protected] 20 +33(0)5 61 33 47 34 21 22 Key words: 23 Variscan belt; French Massif Central; Flow of partially molten crust; Orogenic magmatism; Orogenic plateau; 24 Gravitational collapse. 25 26 Abstract 27 We present here a tectonic-geodynamic model for the generation and flow of partially molten rocks and for 28 magmatism during the Variscan orogenic evolution from the Silurian to the late Carboniferous based on a synthesis 29 of geological data from the French Massif Central. -
Mineralogy and Geochemistry of Ocelli in the Damtjernite Dykes and Sills, Chadobets Uplift, Siberian Craton: Evidence of the Fluid–Lamprophyric Magma Interaction
minerals Article Mineralogy and Geochemistry of Ocelli in the Damtjernite Dykes and Sills, Chadobets Uplift, Siberian Craton: Evidence of the Fluid–Lamprophyric Magma Interaction Anna A. Nosova 1,*, Ludmila V. Sazonova 1,2, Alexey V. Kargin 1 , Elena O. Dubinina 1 and Elena A. Minervina 1 1 Institute of Geology of Ore Deposits, Petrography, Mineralogy and Geochemistry, Russian Academy of Sciences (IGEM RAS), 119017 Moscow, Russia; [email protected] (L.V.S.); [email protected] (A.V.K.); [email protected] (E.O.D.); [email protected] (E.A.M.) 2 Geology Department, Lomonosov Moscow State University, 119991 Moscow, Russia * Correspondence: [email protected]; Tel.:+7-499-230-8414 Abstract: The study reports petrography, mineralogy and carbonate geochemistry and stable iso- topy of various types of ocelli (silicate-carbonate globules) observed in the lamprophyres from the Chadobets Uplift, southwestern Siberian craton. The Chadobets lamprophyres are related to the REE-bearing Chuktukon carbonatites. On the basis of their morphology, mineralogy and relation with the surrounding groundmass, we distinguish three types of ocelli: carbonate-silicate, containing carbonate, scapolite, sodalite, potassium feldspar, albite, apatite and minor quartz ocelli (K-Na-CSO); carbonate–silicate ocelli, containing natrolite and sodalite (Na-CSO); and silicate-carbonate, con- taining potassium feldspar and phlogopite (K-SCO). The K-Na-CSO present in the most evolved Citation: Nosova, A.A.; Sazonova, damtjernite with irregular and polygonal patches was distributed within the groundmass; the patches L.V.; Kargin, A.V.; Dubinina, E.O.; consist of minerals identical to minerals in ocelli. Carbonate in the K-Na-CSO are calcite, Fe-dolomite Minervina, E.A. -
Bulletin of the Geological Society of America Vol
BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA VOL. 69, PP. 1071-1073 AUGUST 1953 DEFINITION OF VOLCANIC BRECCIA BY RICHARD V. FISHER Common usage of the term breccia by most usefulness because of these various definitions' geologists limits it to a rock composed of not only in the matter of grade size but, far angular fragments. The lower-size limit of the more importantly, in the matter of genetic fragments is generally set at 2 mm, the limiting implications. Indeed, in the most recent size for granules and larger particles (Went- glossary of geologic terms (American Geological worth, 1922; 1935). Logically it should follow Institute, 1957), volcanic breccia has been that a volcanic breccia is a breccia composed of defined as a "more or less indurated pyroclastic angular volcanic fragments larger than 2 mm. rock (author's italics) consisting chiefly of Norton (1917, p. 162), in his classification of accessory and accidental angular ejecta 32 mm breccias, includes volcanic breccias under the or more in diameter lying in a fine tuff matrix." heading of subaerial breccias, although he does It is commonly recognized that volcanic not set a size limit for the fragments. He breccias may originate in a variety of ways further subdivides volcanic breccias (p. 170) (Anderson, 1933, p. 215-276; Wentworth and into flow breccia, which forms by fragmentation Williams, 1932, p. 32-33; Gilluly, Waters, and of lava during its flow, and tuff breccia "made up Woodford, 1951, p. 606), and apparently most of fragmental products of explosive eruptions." geologists use the term in a broad sense, but in Reynolds (1928, p. -
Sequence Stratigraphy of the Neoproterozoic Infra Krol Formation and Krol Group, Lesser Himalaya, India
SEQUENCE STRATIGRAPHY OF THE NEOPROTEROZOIC INFRA KROL FORMATION AND KROL GROUP, LESSER HIMALAYA, INDIA GANQING JIANG1, NICHOLAS CHRISTIE-BLICK1, ALAN J. KAUFMAN2, DHIRAJ M. BANERJEE3, AND VIBHUTI RAI4 1 Department of Earth and Environmental Sciences and Lamont-Doherty Earth Observatory of Columbia University, Palisades, New York 10964±8000, U.S.A. 2 Department of Geology, University of Maryland, College Park, Maryland 20742±4211, U.S.A. 3 Department of Geology, University of Delhi, Delhi 110007, India 4 Department of Geology, Lucknow University, Lucknow 226007, India e-mail: [email protected] ABSTRACT: A sequence stratigraphic study of terrigenous and carbonate rocks GEOLOGICAL FRAMEWORK of the Infra Krol Formation and Krol Group in the Lesser Himalaya fold and thrust belt of northern India was undertaken as part of a broader investigation The Infra Krol Formation and Krol Group are part of a Neoproterozoic and Lower of the signi®cance of carbon isotope data in Neoproterozoic successions. Eight Cambrian succession more than 12 km thick, cropping out in the Lesser Himalaya regional stratigraphic discontinuities were traced over a distance of nearly 300 in a series of doubly plunging synclines between Solan in the northwest and Nainital, km, and interpretations were anchored in a series of local studies involving the 280 km to the southeast (Fig. 1; Bhargava 1979; Shanker et al. 1989; Shanker et mapping of key beds and the measurement of closely spaced sections. Three of al. 1993; Shanker et al. 1997; Shanker and Mathur 1992). -
Facies and Mafic
Metamorphic Facies and Metamorphosed Mafic Rocks l V.M. Goldschmidt (1911, 1912a), contact Metamorphic Facies and metamorphosed pelitic, calcareous, and Metamorphosed Mafic Rocks psammitic hornfelses in the Oslo region l Relatively simple mineral assemblages Reading: Winter Chapter 25. (< 6 major minerals) in the inner zones of the aureoles around granitoid intrusives l Equilibrium mineral assemblage related to Xbulk Metamorphic Facies Metamorphic Facies l Pentii Eskola (1914, 1915) Orijärvi, S. l Certain mineral pairs (e.g. anorthite + hypersthene) Finland were consistently present in rocks of appropriate l Rocks with K-feldspar + cordierite at Oslo composition, whereas the compositionally contained the compositionally equivalent pair equivalent pair (diopside + andalusite) was not biotite + muscovite at Orijärvi l If two alternative assemblages are X-equivalent, l Eskola: difference must reflect differing we must be able to relate them by a reaction physical conditions l In this case the reaction is simple: l Finnish rocks (more hydrous and lower MgSiO3 + CaAl2Si2O8 = CaMgSi2O6 + Al2SiO5 volume assemblage) equilibrated at lower En An Di Als temperatures and higher pressures than the Norwegian ones Metamorphic Facies Metamorphic Facies Oslo: Ksp + Cord l Eskola (1915) developed the concept of Orijärvi: Bi + Mu metamorphic facies: Reaction: “In any rock or metamorphic formation which has 2 KMg3AlSi 3O10(OH)2 + 6 KAl2AlSi 3O10(OH)2 + 15 SiO2 arrived at a chemical equilibrium through Bt Ms Qtz metamorphism at constant temperature and =