DOCSLIB.ORG

Glacial Sedimentation of Late Paleozoic Talchir Diamictite, Pench Valley Coalfield, Central India

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Glacial Sedimentation of Late Paleozoic Talchir Diamictite, Pench Valley Coalfield, Central India SATYENDRA M. CASSHYAP* Department of Geology, Aligarh Muslim University, Aligarh, India HAYAT A. QIDWAI* } Glacial Sedimentation of Late Paleozoic Talchir Diamictite, Pench Valley Coalfield, Central India ABSTRACT Permian-Carboniferous diamictite units of the Talchir Forma- tion of the Lower Gondwana group on the Indian peninsula have Three mappable diamictite units occur in the Lower Gondwana been considered glacial in origin (Blanford and others, 1856; Fed- Talchir Formation (Permian-Carboniferous) of the Pench Valley den, 1874; Krishnan, 1960). Subsequent studies of the texture and coalfield of Satpura basin, central India. These diamictite units mineral assemblage of Talchir strata in the Damodar Valley (each about 28 to 45 m thick) are predominantly green, polymictic, coalfields of eastern India recognized both glacial and fluvioglacial and poorly sorted. Portions of the units ':hat are massive diamictite deposits (Rao, 1957; Srivastava, 1961; Niyogi, 1961; Smith, 1963; include a variety of twisted and deformed to tabular and wedge- Ghosh and Mitra, 1970). Locally, evidence for turbidity currents shaped sandstone bodies, as well as thin \enses of conglomerate and was cited by Banerjee (1966). The Pench Valley coalfield of the sandstone that locally exhibit parallel groove markings on the Satpura basin in central India (Fig. 1, inset map) was selected for upper surface. Portions of the units that are stratified diamictite are this investigation because it lies at the western limit of Lower characterized by "grouped" clasts and thin interbeds of siltstone Gondwana deposition and because the Lower Gondwana rocks in and sandstone showing fine, parallel grooves (striae) and linguoid this part have not been studied in detail. ripples where the interbeds occur beneath diamictite. Each diamic- The Talchir diamictite assemblage represents a complex group of tite unit is overlain by an assemblage of interbedded green siltstone, rocks, and a critical re-evaluation is desirable to modify and ex- shale, and sandstone. Such an assemblage contains a variety of pand the sedimentation model and paleogeography. The sedimen- primary depositional structures plus local striated "lonestones." tation model is developed from analysis of stratigraphic and The upper part of the Talchir Formation, the transitional assemb- lithologic characteristics and primary and secondary sedimentary lage, is characterized by horizontally bedded to cross-bedded con- structures of the diamictite units and associated strata. An attempt glomeratic sandstone in which embedded clasts are more rounded is made to reconstruct the sedimentologic evolution of the Talchir than those of the diamictite. strata. A synthesis of the above features discounts the possibility that turbidity currents or mass flows were the sole formative mech- STRATIGRAPHIC SETTING anisms. Alternatively, lithologic and sedimentary characteristics The geologic map of the Pench Valley coalfield was prepared by of the lower Talchir strata and their over-all stratigraphic and tec- C. S. Fox in 1923 to 1925 (Fox, 1934, p. 176). The area was tonic setting strongly favor a glacial origin for the diamictite; this geologically remapped on a scale of 5 cm to 1.58 km (2 in. to 1 mi) corroborates previously published views. We postulate a by one of us (Qidwai) during the winters of 1969 to 1970 and 1970 glaciomarine model, however, to explain the Talchir sedimentation to 1971 (Qidwai, 1972, his Fig. 2). The Talchir Formation overlies in the study area. The ice sheets may have advanced into central Archean rocks and is overlain by the Barakar and Motur Forma- India from the south several times. The overlying transitional as- tions (Fig. 1A). The structural strike is generally southeast; north- semblage may be glaciofluvial in origin. Key words: sedimentology, east dips vary from 3° to 8°. The sedimentary assemblage is over- stratigraphy, diamictite, tillite, Gondwana, late Paleozoic, Talchir, lain by the Cretaceous Deccan Trap. ice transport direction, paleoslope, sedimentary evolution. The Talchir Formation shows a faulted contact with the underly- ing Archean rocks and is exposed in two patches (Fig. 1A). The INTRODUCTION strata in the western area are better exposed than those in the smal- ler eastern area; both areas have been examined for this study. The Recent research on diamictite has improved understanding of the Talchir Formation of the Indian peninsula is characteristically geologic processes that result in the deposition of this rock type and olive green and consists of an interbedded sequence of diamictite, control the lithologic succession associated with it. Initial studies of sandstone, siltstone, and shale, with minor lenses of pebble con- diamictite units have been re-evaluated by detailed analysis to de- glomerate. A series of traverses along drainage courses in the west- termine whether their origin was glacial or whether an alternative ern part has yielded an orderly lithologic sequence that is laterally mechanism, such as subaerial mudflows, subaqueous mass move- traceable (Fig. IB). Table 1 records the recognizable subdivisions ment, or turbidity currents, caused their emplacement. The and corresponding lithologic units of the Talchir Formation. Ap- geologic interpretation of this complex group of rocks should be proximate minimum thickness of the Talchir strata in the western based on integrated studies of lithologic and stratigraphic charac- part is about 250 to 300 m. Plant fossils are more common in the teristics and primary sedimentary structures of both the diamictite middle and upper parts of the formation and are mostly fragments and associated rocks, in addition to consideration of the over-all of Glossopteris. stratigraphic framework and tectonic setting (Thornbury, 1954; The age of the Talchir strata and the overlying Lower Gondwana Flint, 1961; Dott, 1961; Crowell, 1964; Harland, 1965; Schwarz- formations cannot be determined with absolute precision because bach, 1964). of the paucity of faunal remains. The discovery of marine inverte- brate fossils in the Talchir diamictite at Umaria, Manendragarh, and Daltonganj in east-central India has enabled Sastri and Shah * Present address: (Casshyap) Ruhr-Universität Bochum, Institute für Geologie, 4630 Bochum-Querenburg, West Germany; (Qidwai) Department of Atomic Energy, (1964, p. 143) to propose Sakmarian to Artinskian (Early Permian) Atomic Mineral Division, R. K. Puram, New Delhi-110022, India. age for these fossiliferous diamictite outcrops, however. Geological Society of America Bulletin, v. 85, p. 749-760,10 figs., May 1974 749 Downloaded from http://pubs.geoscienceworld.org/gsa/gsabulletin/article-pdf/85/5/749/3418376/i0016-7606-85-5-749.pdf by guest on 26 September 2021 Downloaded from http://pubs.geoscienceworld.org/gsa/gsabulletin/article-pdf/85/5/749/3418376/i0016-7606-85-5-749.pdf by guest on 26 September 2021 GLACIAL SEDIMENTATION OF LATE PALEOZOIC TALCHIR DIAMICTITE, INDIA 751 TABLE 1. LOWER GONDWANA SEQUENCE AND LITHOLOGIC SUBDIVISIONS OF THE TALCHIR FORMATION -| Cyclic units Approximate Description of main lithologie types thickness (m) Cycllc units 800 Red and green mudstone and thin interbeds of gray and green, coarse sandstone in the lower p.jrt, and gray to white, pebbly, coarse to medium sandstone in the upper part 120 Interbedded, coarse to fine, gray sandstone, siltstone, shale, carbonaceous shale, and coal Transitional assemblage D1 40 Interbedded fine, green sandstone, (D) siltstone, and shale D 10 Gray to white, pebbly, coarse sandstone i • A •. Û • Fine clastic rocks C3 60 Predomirantly olive-green laminated shale • A* » • • C2 10 Interbedded sandstone, siltstone, and shale CI 15 Olive-green sandstone Coarse clastic rocks C 28 Olive-green, poorly sorted diamictite Fine clastic rocks B1 6 Gray sandstone, lower contact wavy Coarse clastic rocks B 38 Olive-graen, poorly sorted diamictite Fine clastic rocks A3 5 - 10 01ive-gr<»en sandstone A2 12 - 22 Interbedded green sandstone, siltstone, and shale r=31 IHTERBCODCD SANDSTONE A1 35 Olive-groen sandstone bud AND SHALC Coarse clastic rocks r.v.;| &ANOSTONE A 30 Olive-green, poorly sorted diamictite mAMtcTire Figure 2. Stratigraphic sections of Talchir Formation showing lithologic composi- tion and cyclic units in the western (A, B, and C) and eastern (D) areas. A, Chatua- LITHOLOGIC TYPES AND Hinautia section; B, Budhwara-Naulakhapa section; C, Bhadri section; D, Khirsadoh SEDIMENTARY CHARACTERISTICS section. Columnar sections illustrate gross lithologic composition and cent) units. The most important lithologic types are porphyritic sedimentary characteristics of the Talchir Formation (Fig. 2). The granite (22 to 50 percent), granite gneiss (15 to 44 percent), lime- Talchir strata (Table 1) can be grouped into three lithologic types: stone (5 to 9 percent), quartzose sandstone (2 to 15 percent), basic (1) diamictite units A, B, C; (2) a fine-grained assemblage of sand- extrusive igneous rocks (5 to 9 percent), red sandstone (less than 1 stone, siltstone, and shale occurring above each diamictite (units to 11 percent), banded hematite quartzite (less than 1 to 11 per- A1 to A3, Bl, and CI to C3); and (3) coarse- and fine-grained clas- cent), and shale (less than 1 to 11 percent). Relative proportions tic rocks of the transitional assemblage, represented by units D and persist in groups of clasts of different size fractions. Clast round- D1 (Figs. IB and 2). ness was estimated visually from the chart after Krumbein (1941). Roundness appears to be independent
Load more

Recommended publications
  • 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).
    [Show full text]
  • Part 629 – Glossary of Landform and Geologic Terms
    Title 430 – National Soil Survey Handbook Part 629 – Glossary of Landform and Geologic Terms Subpart A – General Information 629.0 Definition and Purpose This glossary provides the NCSS soil survey program, soil scientists, and natural resource specialists with landform, geologic, and related terms and their definitions to— (1) Improve soil landscape description with a standard, single source landform and geologic glossary. (2) Enhance geomorphic content and clarity of soil map unit descriptions by use of accurate, defined terms. (3) Establish consistent geomorphic term usage in soil science and the National Cooperative Soil Survey (NCSS). (4) Provide standard geomorphic definitions for databases and soil survey technical publications. (5) Train soil scientists and related professionals in soils as landscape and geomorphic entities. 629.1 Responsibilities This glossary serves as the official NCSS reference for landform, geologic, and related terms. The staff of the National Soil Survey Center, located in Lincoln, NE, is responsible for maintaining and updating this glossary. Soil Science Division staff and NCSS participants are encouraged to propose additions and changes to the glossary for use in pedon descriptions, soil map unit descriptions, and soil survey publications. The Glossary of Geology (GG, 2005) serves as a major source for many glossary terms. The American Geologic Institute (AGI) granted the USDA Natural Resources Conservation Service (formerly the Soil Conservation Service) permission (in letters dated September 11, 1985, and September 22, 1993) to use existing definitions. Sources of, and modifications to, original definitions are explained immediately below. 629.2 Definitions A. Reference Codes Sources from which definitions were taken, whole or in part, are identified by a code (e.g., GG) following each definition.
    [Show full text]
  • Stratigraphic Signature of the Late Palaeozoic Ice Age in the Parmeener Supergroup of Tasmania, SE Australia, and Inter- Regional Comparisons
    University of Nebraska - Lincoln DigitalCommons@University of Nebraska - Lincoln Earth and Atmospheric Sciences, Department Papers in the Earth and Atmospheric Sciences of 2010 Stratigraphic signature of the late Palaeozoic Ice Age in the Parmeener Supergroup of Tasmania, SE Australia, and inter- regional comparisons Christopher R. Fielding University of Nebraska-Lincoln, [email protected] Tracy D. Frank University of Nebraska-Lincoln, [email protected] John L. Isbell University of Wisconsin-Milwaukee, [email protected] Lindsey C. Henry University of Wisconsin-Milwaukee Eugene W. Domack Hamilton College, Clinton, NY, [email protected] Follow this and additional works at: https://digitalcommons.unl.edu/geosciencefacpub Part of the Earth Sciences Commons Fielding, Christopher R.; Frank, Tracy D.; Isbell, John L.; Henry, Lindsey C.; and Domack, Eugene W., "Stratigraphic signature of the late Palaeozoic Ice Age in the Parmeener Supergroup of Tasmania, SE Australia, and inter-regional comparisons" (2010). Papers in the Earth and Atmospheric Sciences. 263. https://digitalcommons.unl.edu/geosciencefacpub/263 This Article is brought to you for free and open access by the Earth and Atmospheric Sciences, Department of at DigitalCommons@University of Nebraska - Lincoln. It has been accepted for inclusion in Papers in the Earth and Atmospheric Sciences by an authorized administrator of DigitalCommons@University of Nebraska - Lincoln. Published in Palaeogeography, Palaeoclimatology, Palaeoecology 298 (2010), pp. 70–90; doi:10.1016/j.palaeo.2010.05.023 Copyright © 2010 Elsevier B.V. Used by permission Submitted September 25, 2009; revised April 20, 2010; accepted May 20, 2010; published online June 1, 2010. Stratigraphic signature of the late Palaeozoic Ice Age in the Parmeener Supergroup of Tasmania, SE Australia, and inter-regional comparisons Christopher R.
    [Show full text]
  • Insights Into Chemical Weathering of the Upper Continental Crust from the Geochemistry of Ancient Glacial Diamictites
    Available online at www.sciencedirect.com ScienceDirect Geochimica et Cosmochimica Acta 176 (2016) 96–117 www.elsevier.com/locate/gca Insights into chemical weathering of the upper continental crust from the geochemistry of ancient glacial diamictites Su Li a,b,⇑, Richard M. Gaschnig b,2, Roberta L. Rudnick b,1 a School of Geosciences, China University of Petroleum (East China), Qingdao 266555, China b Geology Department, University of Maryland, College Park, MD 20742-421, USA Received 12 June 2015; accepted in revised form 12 December 2015; Available online 21 December 2015 Abstract Glacial diamictites, with ages ranging from 2900 to 0.01 Ma, record the changing composition of the upper continental crust through time (Gaschnig et al., 2014). Li concentrations and isotopic compositions, combined with Pb isotopic compo- sitions, chemical index of alteration (CIA) values and relative Sr concentrations are used here to assess the degree of chemical weathering recorded in these deposits and the origin of this signature. The d7Li values of most of the diamictites (ranging from À3.9 to +3.5) are lower than those of mantle-derived basalts (+3.7 ± 2, 2r), and the low d7Li values are generally accompa- nied by high CIA and low Sr/Sr* values (or Sr depletion factor, Sr/Sr* = Sr/(Ce*Nd)0.5), reflecting a weathering signature that may have derived from pre-depositional, syn-depositional, and/or post-depositional weathering processes. Profiles through three glacial diamictites with relatively high CIA (a fresh road cut of the Neoproterozoic Nantuo Formation (CIA = 62– 69), and drill cores through the Paleoproterozoic Timeball Hill (CIA = 66–75) and Duitschland Formations (CIA = 84– 91)) do not show evidence of significant post-depositional weathering.
    [Show full text]
  • A Surface Veneer: Sediments and Sedimentary Rocks Earth Portrait of a Planet Fifth Edition Chapter 7
    CE/SC 10110-20110 A Surface Veneer: Sediments and Sedimentary Rocks Earth Portrait of a Planet Fifth Edition Chapter 7 Sediments and Sedimentary Rocks! Sedimentary+rocks+form+layers+like+the+pages+of+a+book.+The+layers+record+a+history+ of+ancient+events+and+ancient+environments+on+the+ever9changing+face+of+planet+ Earth.+Like+a+book,+this+history+can+be+read+by+geologists.+ Sediments and Sedimentary Rocks! Sediment: sand, mud, gravel, accumulations of shells, halite, gypsum, gravel.! Sedimentary Rock: forms at or near the surface of the Earth by precipitation of minerals from water, by growth of skeletal material in organisms, or by the cementing together of shell fragments or loose grains derived from pre-existing rock.! Layers of sediment and sedimentary rock record ancient events and ancient environments.! Study of sediments shows that the Nile River once flowed through a canyon bigger than the Grand Canyon - now it is flowing close to sea level.! In order for this to occur, base level must have been lowered.! Evaporite deposits underlie the floor of the Mediterranean Sea - must have dried up several times in the past (lower sea level).! 3 Sediments & Sedimentary Rocks! Only occur in the upper part of the crust - form a veneer or cover over older, metamorphic rocks (basement).! Can accumulate several kilometers in sedimentary basins.! Contain the bulk of Earths energy resources.! Some sediments transform into soil - essential for life.! 4 Sedimentary Rocks Four major classes:! Biochemical! Clastic! 1) Clastic: cemented solid fragments/
    [Show full text]
  • Ocean Drilling Program Scientific Results Volume
    Barron, J., Larsen, B., et al., 1991 Proceedings of the Ocean Drilling Program, Scientific Results, Vol. 119 6. CENOZOIC GLACIAL RECORD OF THE PRYDZ BAY CONTINENTAL SHELF, EAST ANTARCTICA1 Michael J. Hambrey,2'3 Werner U. Ehrmann,2 and Birger Larsen4 ABSTRACT Drilling was undertaken at five sites (739-743) on ODP Leg 119 on a transect across the continental shelf of Prydz Bay, East Antarctica, to elucidate the long-term glacial history of the area and to examine the importance of the area with respect to the development of the East Antarctic ice sheet as a whole. In addition to providing a record of glacia- tion spanning 36 m.y. or more, Leg 119 has provided information concerning the development of a continental margin under the prolonged influence of a major ice sheet. This has allowed the development of a sedimentary model that may be applicable not only to other parts of the Antarctic continental margin, but also to northern high-latitude continental shelves. The cored glacial sedimentary record in Prydz Bay consists of three major sequences, dominated by diamictite: 1. An upper flat-lying sequence that ranges in thickness from a few meters in inner and western Prydz Bay to nearly 250 m in the outer or eastern parts of the bay. The uppermost few meters consist of Holocene diatom ooze and diatoma- ceous mud with a minor ice-rafted component overlying diamicton and diamictite of late Miocene to Quaternary age. The diamictite is mainly massive, but stratified varieties and minor mudstone and diatomite also occur. 2. An upper prograding sequence cored at Sites 739 and 743, unconformly below the flat-lying sequence.
    [Show full text]
  • A Partial Glossary of Spanish Geological Terms Exclusive of Most Cognates
    U.S. DEPARTMENT OF THE INTERIOR U.S. GEOLOGICAL SURVEY A Partial Glossary of Spanish Geological Terms Exclusive of Most Cognates by Keith R. Long Open-File Report 91-0579 This report is preliminary and has not been reviewed for conformity with U.S. Geological Survey editorial standards or with the North American Stratigraphic Code. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government. 1991 Preface In recent years, almost all countries in Latin America have adopted democratic political systems and liberal economic policies. The resulting favorable investment climate has spurred a new wave of North American investment in Latin American mineral resources and has improved cooperation between geoscience organizations on both continents. The U.S. Geological Survey (USGS) has responded to the new situation through cooperative mineral resource investigations with a number of countries in Latin America. These activities are now being coordinated by the USGS's Center for Inter-American Mineral Resource Investigations (CIMRI), recently established in Tucson, Arizona. In the course of CIMRI's work, we have found a need for a compilation of Spanish geological and mining terminology that goes beyond the few Spanish-English geological dictionaries available. Even geologists who are fluent in Spanish often encounter local terminology oijerga that is unfamiliar. These terms, which have grown out of five centuries of mining tradition in Latin America, and frequently draw on native languages, usually cannot be found in standard dictionaries. There are, of course, many geological terms which can be recognized even by geologists who speak little or no Spanish.
    [Show full text]
  • Gravels, Conglomerates, and Breccias
    Gravels, Conglomerates, and Breccias Introduction A gravel is an unconsolidated accumulation of rounded fragments larger than sands (Larger than 2 mm.). Material in the 2 to 4 mm. range has been termed granule gravel or very fine gravel. Siliciclastic sedimentary rocks that consist predominantly of consolidated accumulation gravel-size (>2mm) clasts are called conglomerates. The Latin-derived term rudite is also sometimes used for these rocks. Conglomerates are common rocks in stratigraphic sequences of all ages, but make up less than about one percent by weight of the total sedimentary rock mass. In contrast to sandstones, conglomerates contain a significant fraction of gravel-size particles. The percentage of gravel-size particles required to Dr. Zaid A. Malak (Dept. of Geology—Mousl University) Email ([email protected]) distinguish a conglomerate from a sandstone or mudstone (shale). Folk (1974) sets the boundary between gravel and gravelly mud or gravelly sand at 30 percent gravel. That is, he considers a deposit with as little as 30 percent gravel-size fragments to be a gravel. On the other hand, Gilbert (Williams et al., 1982) indicates that a sedimentary rock must contain more than 50 percent gravel-size fragments to be called a conglomerate. Siliciclastic sedimentary rocks that contain fewer than 50 percent gravel-size clasts (possibly fewer than 30 percent according to Folk’s usage) are conglomeratic sandstones (pebbly sandstone) or conglomeratic mudstones (pebbly mudstone). Gilbert reserves these terms for rocks with less than about 25 percent gravel-size clasts. Crowell (1957) suggested the term pebbly mudstone for any poorly sorted sedimentary rock composed of dispersed pebbles in an abundant mudstone matrix.
    [Show full text]
  • Neogene Marine Isotopic Evolution and the Erosion of Lesser Himalayan Strata: Implications for Cenozoic Tectonic History ∗ Paul M
    Earth and Planetary Science Letters 417 (2015) 142–150 Contents lists available at ScienceDirect Earth and Planetary Science Letters www.elsevier.com/locate/epsl Neogene marine isotopic evolution and the erosion of Lesser Himalayan strata: Implications for Cenozoic tectonic history ∗ Paul M. Myrow a, , Nigel C. Hughes b, Louis A. Derry c, N. Ryan McKenzie d,e, Ganqing Jiang f, A. Alexander G. Webb g, Dhiraj M. Banerjee h, Timothy S. Paulsen i, Birendra P. Singh j a Department of Geology, Colorado College, Colorado Springs, CO 80903, USA b Department of Earth Sciences, University of California, Riverside, CA 92521, USA c Department of Earth and Atmospheric Sciences, Cornell University, Ithaca, NY 14853, USA d Jackson School of Geosciences, University of Texas, Austin, TX 78713, USA e Department of Geology and Geophysics, Yale University, New Haven, CT 06511, USA f Department of Geosciences, University of Nevada, Las Vegas, NV 89154, USA g Department of Geology & Geophysics, Louisiana State University, LA 70803, USA h Department of Geology, University of Delhi, Delhi, 110007, India i Department of Geology, University of Wisconsin, Oshkosh, WI 54901, USA j Department of Geology, Panjab University, Chandigarh, 160014, 54901, India a r t i c l e i n f o a b s t r a c t Article history: An extensive, northward deepening blanket of Neoproterozoic and Cambrian sedimentary rocks once Received 30 September 2014 extended from the Himalayan margin far onto the Indian craton. Cambrian deposits of this “upper Lesser Received in revised form 29 January 2015 Himalayan” succession, which include deposits of the “outer” Lesser Himalaya tectonic unit, are enriched Accepted 12 February 2015 187 in radiogenic Os.
    [Show full text]
  • Paleoenvironmental and Paleotectonic Significance of Neoproterozoic Diamictites in Actively Rifting Basins
    Paleoenvironmental and Paleotectonic Significance of Neoproterozoic Diamictites in Actively Rifting Basins by Kirsten Kennedy A thesis submitted in conformity with the requirements for the degree of Doctorate of Philosophy Department of Earth Sciences University of Toronto © Copyright by Kirsten Kennedy 2017 Paleoenvironmental and Paleotectonic Significance of Neoproterozoic Diamictites in Actively Rifting Basins Kirsten Kennedy Doctorate of Philosophy Department of Earth Sciences University of Toronto 2017 Abstract Thick successions of poorly-sorted admixtures of clasts and matrix (diamictite) are widely regarded as evidence for synchronous ‘panglacials’ of global extent during the Cryogenian period (c. 720-635 Ma). In this thesis, diamictite facies are examined in detail using an impressive collection of newly available sub-surface data consisting of some 300 km of drill core through the Grand Conglomérat, Democratic Republic of Congo, and by field investigations of the exceptionally well-exposed Kingston Peak Formation in eastern California, USA. Diamictites are shown to be of mass flow origin (debrites) present within thick (<3 km) successions of genetically-related sediment gravity flow facies (olistostromes, slumps, and turbidites) deposited in deep-water within rapidly subsiding rift basins. Thick slope aprons likely formed at the base of fault scarps and tectonically oversteepened and unstable gravelly slopes that periodically underwent collapse, forming diamictite as a consequence of mixing between slumped material and basinal material during transport. The term ‘mixtite’ is a useful descriptive term. A primary tectonic control dictated the basin stratigraphy such that thick diamictite-bearing mass flow successions can be related to phases of accelerated subsidence (i.e. ‘rift climax’); the internal stratigraphy of diamictite successions identifies higher order episodic pulses of faulting.
    [Show full text]
  • Ghaub Thumb Table
    A Neoproterozoic Rock Sample Suite: Evidence for the Snowball Earth Timothy Fox¹, Eugene Domack¹, and Paul Hoffman 2 [email protected], [email protected] Hamilton College, 198 College Hill Road, Clinton NY 13323 [email protected] Geological Museum Rm 203D , 24 Oxford St., Cambridge, MA 02138 Table of Contents The Namibian samples-thumbnail descriptions 2 Namibia TS-1 3 What are Cap Carbonates? 4 Namibia TS-3 5 Namibia TS-12 6 Namibia TS-15 7 Namibia AB-1 8 Namibia TS-20 9 Namibia TS-7 11 The East Greenland samples-thumbnail descriptions 12 East Greenland #36 13 East Greenland #22 14 East Greenland #17 15 East Greenland #7 16 East Greenland #38 17 East Greenland #29 18 East Greenland #50 19 East Greenland D-6 20 Unique mineral fans from Canada’s Mackenzie Mtns. & W. Africa 21 -thumbnail descriptions Northwest Canada PFH-4 22 Northwest Canada P10A 23 West Africa PFH-1 & PFH-2 24 Northwest Canada PFH-3 25 1 0 Sample Characteristics Depositional Context Lwr. TS-1 Marine “cap” carbonate Maiberg deposited directly Fine-grained above the Ghaub 5 carbonate laminite. glacial formation, suggests rapid environmental change. 10 TS-3 Stratified carbonate mud with sediment Represents a major gravity (debris flow) deglaciation event at 15 deposits and the end of the global Section 2-West significant ice rafted Marinoan glacial. debris. 20 TS-12 Stratified carbonate Interbedded diamictite 40 mud diamictite with and sediment gravity sediment gravity debris flows, deposited debris flow deposits as ice receded from the and ice rafted debris. continental shelf. UPPER GHAUB 45 TS-15 50 Massive clast-rich Basal tillite deposited meters 0 diamictite.
    [Show full text]
  • Impacts, Tillites, and the Breakup of Gondwanaland
    University of Nebraska - Lincoln DigitalCommons@University of Nebraska - Lincoln NASA Publications National Aeronautics and Space Administration 1993 Impacts, Tillites, and the Breakup of Gondwanaland Verne R. Oberbeck NASA Ames Research Center John R. Marshall NASA Ames Research Center Hans Aggarwal NASA Ames Research Center Follow this and additional works at: https://digitalcommons.unl.edu/nasapub Part of the Physical Sciences and Mathematics Commons Oberbeck, Verne R.; Marshall, John R.; and Aggarwal, Hans, "Impacts, Tillites, and the Breakup of Gondwanaland" (1993). NASA Publications. 74. https://digitalcommons.unl.edu/nasapub/74 This Article is brought to you for free and open access by the National Aeronautics and Space Administration at DigitalCommons@University of Nebraska - Lincoln. It has been accepted for inclusion in NASA Publications by an authorized administrator of DigitalCommons@University of Nebraska - Lincoln. ARTICLES Impacts, Tillites, and the Breakup of Gondwanaland' Verne R. Oberbeck, JohnR. Marshall, and Hans Aggarwal2 NASA Ames ResearchCenter, Moffett Field CA 94035, USA ABSTRACT Mathematicalanalysis demonstratesthat substantial impact craterdeposits should have been producedduring the last 2 Gy of Earth'shistory. Textures of impactdeposits are shown to resembletextures of tillitesand diamictites of Precambrianand youngerages. The calculatedthickness distribution for impact craterdeposits produced during 2 Gy is similarto that of tillitesand diamictites<2 Ga. We suggest,therefore, that some tillites/diamictitescould
    [Show full text]