DOCSLIB.ORG

Subantarctic Macrotidal Flats, Cheniers and Beaches in San Sebastian Bay, Tierra Del Fuego, Argentina

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Subantarctic Macrotidal Flats, Cheniers and Beaches in San Sebastian Bay, Tierra Del Fuego, Argentina View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by EPrints Complutense Subantarctic macrotidal flats, cheniers and beaches in San Sebastian Bay, Tierra Del Fuego, Argentina a, b d Federico Vilas * , Alfredo Arche , Marcelo Ferrero C, Federico Isla a Universidad de Vigo, Facultad de Ciencias, Dpto. de Geociencias Marinas y Ordenacion del Territorio, Aptdo. 874, 36.200 Vigo, Spain b Instiluto de Geologia Economica, c.S.l.C.-UC.M, Facultad de Geologia, 28040 Madrid, Spain C Secretaria de Mineria. Avda. de Santa Fe 1542, 1060 Buenos Aires, Argentina d CONICET, Centro de Ge% gia de Costas y del Cuaternario, CC-722, 7600 Mar de Plata, Argentina Abstract San Sebastian Bay is a large, semicircular coastal embayment situated on the Atlantic coast of Tierra del Fuego, Argentina. It is a high-energy, subantarctic environment with a tidal range of 10.4 m, influenced by large waves of Atlantic and local origin and swept by constant, strong westerly winds. A 17 km long gravel spit protects the Northern part of the Bay giving rise to a gradient in sedimentary processes. From south to north, are seven distinct sedimentary environments. Coastal sedimentation started at least 5200 years before present (BP) and a rapid progradation related to a relative sea-level drop has infilled about 6 kilometres of the Bay with a sedimentary sequence 10-11 m thick. 14-C dating of unabraded shells in the Chenier ridges of the relict part of the complex allows for a precise reconstruction of the stages of the progradation, that has slowed from 2.35 m/year at 5000 years BP to 0.6 m/year at present. The possible causes of the sea-level drop are discussed. Keywords: Tierra del Fuego; macrotidal sedimentation; subantarctic climate; sea-level; glacio-isostatic rebound; chenier formation 1. Introduction 1980; Da\rymple et aI., 1990), among others. Some other well known examples are dominated by marine Macrotidal areas with tidal ranges over 8 m are tidal processes such as the Wash (UK) (Evans, 1965) relatively poorly studied in comparison with mesoti­ and Jade Bay (Germany) (Reineck, 1958, 1972), dal (range 2-4 m) areas, Some of them are estuarine Taizhou Bay (China) (Ren, 1986), Bohai Sea (China) in character, such as the Severn River (UK) (Kirby (Wang, 1983) and Inchon Bay (Korea) (Frey et aI., and Parker, 1982; Harris and Collins, 1985; Allen, 1988, 1989). 1987, 1988, 1990), Seine Estuary-Mont Saint Michel In the Southern Hemisphere, macrotidal areas are (France) (Larsonneur, 1982; A voine, 1986; A voine even less well known even though the tidal ranges and Larsonneur, 1987), and the Bay of Fundy and tidal flats at the Atlantic mouth of the Magellan (Canada) (Knight and Dalrymple, 1975; Amos et aI., Strait and the Atlantic Coast of Tierra del Fuego are among the largest in the world. The authors con­ ( , Corresponding author. Fax: + 34-8681-2556; E-mail: ducted surveys of San Sebastian Bay Fig. 1) be­ [email protected] tween 1985 and 1988 aimed at characterising the N - 53° 00' S. t G CERRO <I Z S···. t- ... ... .. .. Z .... / , W ,- <!) .' Il: W <I ...J .. PUNTA DE """" :r ARENAS u C '�:' BAY OF SAN SEBASTIAN PLAYA DE CHORRILLOS O IOKm. _��",=�_=, I A B Fig. I. (A) Map of situation. (B) The Bay of San Sebastian and different physiographic sectors (A to G). Dotted lines are surveyed profiles sampling stations. RG: Rio Grande, RA: Rio Gallegos, PA: PU.nta Arenas, EM: Strait of Magellan, CH: Cape Horn, US: Ushuaia. Location of profiles shown in Fig. 15 are indicated. sedimentary subenvironments, sedimentary pro­ most of them rich in organic remains, allowing for cesses, sequences, and the Quaternary evolution of C-14 dating. The quantification and interpretation of the area. the sea-level fall and its causes was another goal of The Bay presents an interesting combination of our research. physiographic features: extreme macrotidal regime, high latitude, subantarctic climate, fine-grained sedi­ mentation in a high-energy environment and related 2. Location wave- and wind-dominated areas. The bay could provide an alternative example to the classic areas 2.1. Geographic setting listed above and some guidance for the interpretation of ancient, fine-grained, marine deposits. San Sebastian Bay is a coastal embayment situ­ The San Sebastian Bay area exhibits a series of ated in the North of the Argentinean territory of the features which could be interpreted as representing a Isla Grande de Tierra del Fuego (Fig. 1); it lies Holocene fall of sea level of eustatic and/or isostatic between 63° 40' and 63° 48' long. W and 53° 00' origin, such as raised beaches and chenier ridges, and 53° 25' lat. S. « z W f-­ .....J Z I W l') U a::: « " PREVAILING BA Y OF ======:;» WIND 2 SAN SE BASTIAN , , I' N I' t " o 2 3 4 Km. , I SAN SEBASTIAN CHORRILLOS (Y. P. F. DOCK) Fig. 2. Map of the Bay. (A) Gravel beaches of Peninsula del Paramo, (B) Muddy tidal flat with tidal channels, (C) Cheniers and muddy tidal flat without tidal channels, (D) Beach complex of San Sebastian, (E) Cliffs of Punta Basilica, (F) Barrier Beach-Lagoon Complex of Chorrillos, and (G) Fossil sediments deposited during Holocene times. 1 and 2 are the surveyed profiles represented in detail in Fig. 16. The Bay is roughly semicircular in shape, measur­ cesses and rates of sedimentation in the area. Porter ing approximately 40 km from north to south and 25 et a!. (1984) described the Holocene sea level fluctu­ km from east to west (Fig. 2). Astronomic tides ations in the Magallanes-Beagle region, Heusser and range from 3A m to lOA m (Servicio de Hidrografia Rabassa (1987) described and interpreted the cli­ Naval, 1987, 1988). The average rainfall is 300-320 matic changes and glacial retreat stages in the last mm/yr, the prevailing wind comes from the west, 12,000 years in the same area and Rutter et a!. exceeding 60 km/h for more than 200 days per year, (1989) correlated the Quaternary deposits along the with occasional gusts up to 155 km/h; the stability Patagonian and Fuego coastline. of the cyclone patterns in the subantarctic region Vilas et a!. (1987) and Isla et a!. (1991) described (50' to 65' lat S) is responsible for the small varia­ the main sedimentary sequences, the sediment source tion of wind direction. Maximum summer tempera­ areas and the winter and summer wave regimes in tures reach 16°C-18°C, while in winter minimum San Sebastian Bay that occur in two areas with temperatures of - 20'C occur frequently with peri­ different characteristics: (1) a wave-dominated gravel ods of several months when the average temperature spit and (2) a tide-dominated mud flat Bujalesky et is below O°C and the sea water freezes (Servicio de a!. (1987) described the Paramo Peninsula gravel Metereol6gico Nacional, 1986). spit, and Isla (1993) described the gravel segregation and annouring processes in the Paramo Peninsula, 2.2. Geologic setting and the coastal spit that partially closed San Sebas­ tian Bay. The bedrock of the area is the Miocene Carmen The Bay is flanked to the north and the south by Silva Formation (Codignotto and Malumian, 1981) cliffs which at present are undergoing erosion; the consisting of deltaic fine sands and silts. It was northern cliffs are composed of Pleistocene Tills, deeply eroded during the first and largest Patagonian whereas the southern ones comprise the fine-grained, Glaciation (Caldenius, 1932) by a glacier coming siliciclastic, Miocene Cannen Silva Formation. Sedi­ from the Patagonian Iceshield, flowing to the NE mentation occurs in two areas with very different from Dawson Island and eroding in the last 15,000 characteristics (Fig. 2): the Peninsula del Paramo years the Inutil Bay (Chile)-San Sebastian Bay (Zone A), composed of gravel beaches, and the inner (Argentina) depression. A later, Pleistocene glacial coast of the Bay (Zones B-F), where muddy tidal period took place in the area and the Tapera Sur Till flats and sand-gravel beaches are found. As these was deposited (Codignotto, 1979, 1983). Submerged sedimentary environments prograded seawards dur­ moraines at a depth of 5 m have been recognised in ing the Holocene, these coastal sediments covered the shelf, NE of San Sebastian Bay (TOTAL AUS­ most of the much wider original San Sebastian Bay TRAL-GEOMATTER, 1980) to the west, and extensive eolian deposits cover most Raedecke (1978) made reference to several of the Holocene deposits. moraine systems, located between Bahia Inutil and This paper deals with the sedimentary processes Bahia de San Sebastian and their possible succession and deposits of the intertidal area (Fig. 2, Zones B to and Codignotto and Malumian (1981) compiled the F). The sedimentology of the Peninsula del Paramo geology of the Northern Tierra del Fuego and men­ Spit (Fig. 2, Zone A) has been discussed previously tioned the 'rhythmic topography' of the Holocene by Isla et a!. (1991) sediments in the San Sebastian Bay area. More recent research work was specifically aimed 3. Research methods at establishing the succession of glacial and inter­ glacial periods, the stratigraphy of moraines and The different subenvironments required specific coastal sediments and present-day sedimentary pro- research methods according to their dynamics and Fig. 3. (overleaf) Several aspects of the intertidal area north of the Bay. (A) Straight main tidal channel, (B) Sinuous secondary tidal channel, (C) SpideIWeb structure, (D) View across a main tidal channel. A c- - o grain size. Two methodologies were employed, one deposited during the Holocene in a phase of active for tidal flats and another for sandy and gravel coastal progradation and partly covered by eolian beaches.
Load more

Recommended publications
  • (LOWER PENNSYLVANIAN) in the PERMIAN BASIN Wayne R. Wright Bureau of Economic Geol
    DEPOSITIONAL HISTORY OF THE ATOKAN SUCCESSION (LOWER PENNSYLVANIAN) IN THE PERMIAN BASIN Wayne R. Wright Bureau of Economic Geology Jackson School of Geosciences The University of Texas at Austin Austin, Texas ABSTRACT Atokan-age units in the Permian Basin record a 2nd-order transgression, with aerially restricted, lower Atokan fluvial to shallow-marine siliciclastics followed by pervasive carbonate deposition. In general, Atokan-age siliciclastics dominated deposition in the west of the Permian Basin while carbonate deposition dominated throughout the rest of the basin. Predominance of carbonate facies across most of the Permian Basin is due to (1) lack of siliciclastic supply, (2) overall 2nd-order rising sea level, and (3) progradation of the Upper Marble Falls Formation onto the Eastern Shelf. Progradation was due partly to lower accommodation to the west and backstepping/retreat from encroaching Atokan deltaics to the east. The beginning of the Atokan is marked by a sea-level drop and subsequent lowstand conditions. A sequence boundary separates the Atokan from the underlying Morrowan carbonate section throughout the Permian Basin. Siliciclastic deposition in and around the Permian Basin is more aerially restricted than in the Morrowan. The earliest Atokan lowstand event is manifested in alluvial and fluvial incised-valley sediments in Lea County, New Mexico, and the Broken Bone Graben (Cottle County, Texas); fan- delta deposits in the Palo Duro Basin and Taylor Draw field (Upton County, Texas); and 1 post-Lower Marble Falls–pre-Upper Marble falls conglomerates (Gibbons Formation?) on the Llano Uplift. Following the lowstand event, a 2nd-order transgression appears to have dominated throughout the rest of the Atokan; however 3rd- and 4th-order, high- amplitude, sea-level fluctuations also occurred.
    [Show full text]
  • Depositional Setting and Reservoir-Scale
    DEPOSITIONAL SETTING AND RESERVOIR-SCALE ARCHITECTURE OF SANDSTONE BODIES OF THE GREEN RIVER FORMATION IN EVACUATION CREEK, DRAGON QUADRANGLE, EASTERN UINTA BASIN, UTAH by T. Ryan O’Hara A thesis submitted to the Faculty and the Board of Trustees of the Colorado School of Mines in partial fulfillment of the requirements for the degree of Master of Science (Geology) Golden, Colorado Date _____________ Signed: ________________________________ T. Ryan O’Hara Signed: ________________________________ Dr. J. Frederick Sarg Thesis Advisor Golden, Colorado Date _____________ Signed: ________________________________ Dr. Paul Santi Professor and Head Department of Geology and Geologic Engineering ii ABSTRACT The Green River Formation is an Eocene lacustrine deposit that is present in several Rocky Mountain basins. In the Uinta basin, the Green River Formation has produced large amounts of oil and gas from many fields, the largest being the Greater Altamont-Bluebell field in the northern margin of the basin, the Monument Butte and Natural Buttes fields in the central region, and the Greater Red Wash field in the northeastern part of the basin. In addition, the Green River Formation contains one of the largest oil shale deposits in the world. The Uinta and Piceance basins are estimated to contain 1.32 trillion barrels and 1.53 trillion barrels respectively of total in-place oil shale resource. This study focuses on littoral to sublittoral sandstone deposition of the Green River Formation in the eastern Uinta basin of Utah, in Evacuation Creek, near the Utah-Colorado border. This area contains extensive and continuous outcrop of the Green River Formation exposed in steep cliffs and gullies, and allows for the study of these units at the reservoir-scale.
    [Show full text]
  • U.S. Geological Survey Bulletin 1839-G, H
    Stratigraphic Framework of Cambrian and Ordovician Rocks in the Central Appalachian Basin from Morrow County, Ohio, to Pendleton County, West Virginia Depositional Environment of the Fincastle Conglomerate near Roanoke, Virginia U.S. GEOLOGICAL SURVEY BULLETIN 1839-G, H i i i I ' i ' i ' X- »-v l^,:^ Stratigraphic Framework of Cambrian and Ordovician Rocks in the Central Appalachian Basin from Morrow County, Ohio, to Pendleton County, West Virginia By ROBERT T. RYDER Depositional Environment of the Fincastle Conglomerate near Roanoke, Virginia By CHRYSA M. CULLATHER Chapters G and H are issued as a single volume and are not available separately U.S. GEOLOGICAL SURVEY BULLETIN 1839-G, H EVOLUTION OF SEDIMENTARY BASINS-APPALACHIAN BASIN U.S. DEPARTMENT OF THE INTERIOR MANUEL LUJAN, Jr., Secretary U.S. GEOLOGICAL SURVEY DALLAS L. PECK, Director Any use of trade, product, or firm names in this publication is for descriptive purposes only and does not imply endorsement by the U.S. Government UNITED STATES GOVERNMENT PRINTING OFFICE: 1992 For sale by Book and Open-File Report Sales U.S. Geological Survey Federal Center, Box 25425 Denver, CO 80225 Library of Congress Cataloging in Publication Data (revised for vol. G-H) Evoluation of sedimentary basins Appalachian basin. (U.S. Geological Survey bulletin ; 1839 A-D, G-H) Includes bibliographies. Supt. of Docs. no.:19.3:1839-G Contents: Horses in fensters of the Pulaski thrust sheet, southwestern Virginia / by Arthur P. Schultz [etc.] Stratigraphic framework of Cam­ brian and Ordovician rocks in central Appalachian basin from Morrow County, Ohio, to Pendleton County, West Virginia / by Robert T.
    [Show full text]
  • Geological Survey Standards. CONTENTS
    UNITED STATES DEPARTMENT OF THE INTERIOR GEOLOGICAL SURVEY Depositional Environment of the Middle Proterozoic Spokane Formation-Empire Formation Transition Zone, West-Central Montana By James W. Whipple Open-File Report 80-1232 1980 This report is preliminary and has not been edited or reviewed for conformity with U.S. Geological Survey standards. CONTENTS Page Introduction*........................................................... 1 Acknowledgments.................................................... A Purpose and scope.................................................. A Previous studies................................................... A Geologic setting................................................... 5 Stratigraphic subdivision.......................................... 6 Primary sedimentary structures.......................................... 7 Bedding and lamination............................................. 8 Graded lamination............................................. 8 Planar lamination............................................. 11 Rhythmic sand and mud bedding................................. 1A Wavy lamination............................................... 1A Ripple bedding and lamination................................. 17 Algal lamination and loferites................................ 19 Bedding-plane marks and imprints................................... 19 Subaerial shrinkage cracks.................................... 21 Subaqueous shrinkage cracks................................... 21 Raindrop impressions.........................................
    [Show full text]
  • A New Late Permian Burnetiamorph from Zambia Confirms Exceptional
    fevo-09-685244 June 19, 2021 Time: 17:19 # 1 ORIGINAL RESEARCH published: 24 June 2021 doi: 10.3389/fevo.2021.685244 A New Late Permian Burnetiamorph From Zambia Confirms Exceptional Levels of Endemism in Burnetiamorpha (Therapsida: Biarmosuchia) and an Updated Paleoenvironmental Interpretation of the Upper Madumabisa Mudstone Formation Edited by: 1 † 2 3,4† Mark Joseph MacDougall, Christian A. Sidor * , Neil J. Tabor and Roger M. H. Smith Museum of Natural History Berlin 1 Burke Museum and Department of Biology, University of Washington, Seattle, WA, United States, 2 Roy M. Huffington (MfN), Germany Department of Earth Sciences, Southern Methodist University, Dallas, TX, United States, 3 Evolutionary Studies Institute, Reviewed by: University of the Witwatersrand, Johannesburg, South Africa, 4 Iziko South African Museum, Cape Town, South Africa Sean P. Modesto, Cape Breton University, Canada Michael Oliver Day, A new burnetiamorph therapsid, Isengops luangwensis, gen. et sp. nov., is described Natural History Museum, on the basis of a partial skull from the upper Madumabisa Mudstone Formation of the United Kingdom Luangwa Basin of northeastern Zambia. Isengops is diagnosed by reduced palatal *Correspondence: Christian A. Sidor dentition, a ridge-like palatine-pterygoid boss, a palatal exposure of the jugal that [email protected] extends far anteriorly, a tall trigonal pyramid-shaped supraorbital boss, and a recess †ORCID: along the dorsal margin of the lateral temporal fenestra. The upper Madumabisa Christian A. Sidor Mudstone Formation was deposited in a rift basin with lithofacies characterized orcid.org/0000-0003-0742-4829 Roger M. H. Smith by unchannelized flow, periods of subaerial desiccation and non-deposition, and orcid.org/0000-0001-6806-1983 pedogenesis, and can be biostratigraphically tied to the upper Cistecephalus Assemblage Zone of South Africa, suggesting a Wuchiapingian age.
    [Show full text]
  • Stratigraphy and Sedimentology of a Dry to Wet Eolian Depositional System, Burns Formation, Meridiani Planum, Mars
    Earth and Planetary Science Letters 240 (2005) 11–72 www.elsevier.com/locate/epsl Stratigraphy and sedimentology of a dry to wet eolian depositional system, Burns formation, Meridiani Planum, Mars J.P. Grotzinger a,*, R.E. Arvidson b, J.F. Bell III c, W. Calvin d, B.C. Clark e, D.A. Fike a, M. Golombek f, R. Greeley g, A. Haldemann f, K.E. Herkenhoff h, B.L. Jolliff b, A.H. Knoll i, M. Malin j, S.M. McLennan k, T. Parker e, L. Soderblom g, J.N. Sohl-Dickstein b, S.W. Squyres b, N.J. Tosca k, W.A. Watters a a Massachusetts Inst. of Technology, Earth, Atmos. and Planetary Sci., Cambridge, MA 02139, USA b Department Earth and Planetary Sciences, Washington University, St. Louis, MO 63130, USA c Department of Astronomy, Space Sciences Bldg. Cornell University, Ithaca, NY 14853, USA d University of Nevada, Reno, NV 89501, USA e Lockheed Martin Corporation, Littleton, CO 80127, USA f Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, USA g Department Geological Sciences, Arizona State University, Box 871404, Tempe, AZ 85287-1404, USA h U.S. Geological Survey, Flagstaff, AZ 86001, USA i Botanical Museum, Harvard University, Cambridge MA 02138, USA j Malin Space Science Systems, Inc., San Diego, CA 92191, USA k Department of Geosciences, State University of New York, Stony Brook, NY 11794-2100, USA Accepted 22 September 2005 Editor: A.N. Halliday Abstract Outcrop exposures of sedimentary rocks at the Opportunity landing site (Meridiani Planum) form a set of genetically related strata defined here informally as the Burns formation.
    [Show full text]
  • Stratigraphy and Petrology of Mississippian, Pennsylvanian And
    STRATIGRAPHY AND PETROLOGY OF MISSISSIPPIAN, PENNSYLVANIAN, AND PERMIAN ROCKS IN THE MAGDALENA AREA, SOCORRO COUNTY, NEW MEXICO Open-File Report 54 New Mexico Bureau of Mines and Mineral Resources by William Terry Siemers December 1973 TABLEOFCONTENTS INTRODUCTION Area of Study Purpose of Study Method of Study Location and Accessibility ACKNOWLEDGMENTS 5 PALEOTECTONIC SETTING 6 MISSISSIPPIAN PERIOD 11 i Prekious Work 11 Regional Stratigraphy 11 Northern New Mexico 13 south- CentralNew Mexico 13 Southwestern New Mexico 14 Local Stratigraphy 16 Tip Top Mountain 16 *, North Baldy 20 North Fork Canyon 23 Stratigraphic Summary 26 Petrography 27 Caloso Formation 27 Kelly Limestone 28 PENNSYLVANIAN PERIOD 34 Previous Work 34. RegionalStratigraphy 38 Northern New Mexico 38 I Central New Mexico 39 1 Southwestern New Mexico 41 Local Stratigraphy 42 Tip Top Mountain 48 /' c. Sandia Formation 49 ' Madera Limestone 51 North Fork Canyon 52 Sandia Formation 53 Madera Limestone 55 North Baldy 56 Summary of Pennsylvanian Sections 62 ~~ ~ .. 11 Petrography 63 Sandia Formation 63 Madera Limestone 67 ROCKS OF QUESTIONED AGE 72 Bursum Farmation 73 Ab0 Formation 73 c Yeso Formation 75 Glorieta Sandstone 76 San Andres Formation 76 Comparison of Olney Ranch and Tres Montosas 'sections 76 . with Permian and Pennsylvanian Formations Thickness 76 Sedimentary Structures 77 Lithology 78 ENVIRONMENTS OF DEPOSITION 94 Caloso Formation 94 Kelly Limestone 95 Sandia Formation 96 . Quartzite 96 . Shale 97 Limestone 97 Madera Limestone 97 SUMMARY AND CONCLUSIONS 98 REFERENCES 100 APPENDICES 108 Appendix I: Stratigraphic Columns 109 Appendix II: Sedimentary Petrology 118 Appendix 111: Classification Systems 127 c iii LIST OF FIGURES Figure Page 1.
    [Show full text]
  • High-Resolution Stratigraphy and Lithology of an Outcrop Within the Grundy Formation (Pennsylvanian), Harlan County, Southeast Kentucky
    Eastern Kentucky University Encompass Geosciences Undergraduate Theses Geosciences Spring 5-2020 High-resolution Stratigraphy and Lithology of an Outcrop within the Grundy Formation (Pennsylvanian), Harlan County, Southeast Kentucky Andrew Hensley Eastern Kentucky University Follow this and additional works at: https://encompass.eku.edu/geo_undergradtheses Recommended Citation Hensley, Andrew, "High-resolution Stratigraphy and Lithology of an Outcrop within the Grundy Formation (Pennsylvanian), Harlan County, Southeast Kentucky" (2020). Geosciences Undergraduate Theses. 7. https://encompass.eku.edu/geo_undergradtheses/7 This Restricted Access Thesis is brought to you for free and open access by the Geosciences at Encompass. It has been accepted for inclusion in Geosciences Undergraduate Theses by an authorized administrator of Encompass. For more information, please contact [email protected]. High-resolution Stratigraphy and Lithology of an Outcrop within the Grundy Formation (Pennsylvanian), Harlan County, Southeast Kentucky By Andrew Hensley Submitted to Walter S. Borowski Senior Thesis (GLY 499) May 2020 i TABLE OF CONTENTS Abstract……………………………………………………………………………………… 1 Introduction………………………………………………………………………….…….... 2 Methods……………………………………………………………………………………... 2 Results………………………………………………………………………………………..3 Coarsening-upward Sequence 1…………………..…………………………………5 Coarsening-upward Sequence 2…………………..…………………………………7 Coarsening-upward Sequence 3…………………..…………………………………9 Coarsening-upward Sequence 4…………………………………………………….11 Coarsening-upward Sequence
    [Show full text]
  • Sedimentology, Stratigraphy, and Geochronology of the Proterozoic Mazatzal Group, Central Arizona
    Sedimentology, stratigraphy, and geochronology of the Proterozoic Mazatzal Group, central Arizona RoÂnadh Cox² Department of Geosciences, Williams College, Williamstown, Massachusetts 01267, USA Mark W. Martin³ Department of Earth and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA Jana C. Comstock Department of Geosciences, Williams College, Williamstown, Massachusetts 01267, USA Laura S. Dickerson Geology Department, Colorado College, Colorado Springs, Colorado 80903, USA Ingrid L. Ekstrom Department of Geology, Amherst College, Amherst, Massachusetts 01002, USA James H. Sammons Department of Geology, Washington and Lee University, Lexington, Virginia 24450, USA ABSTRACT Group. When tectonic activity ceased, how- the Proterozoic tectonic block known as the ever, the surrounding highlands were planed Mazatzal block (Karlstrom and Bowring, Quartzite, conglomerate, and shale of the down by erosion, and detritus from a wider 1993) (Fig. 2) and represents the transition Mazatzal Group record the ®lling of a Prot- variety of source rocks was funneled into the from tectonically active arc and marginal- erozoic intra-arc basin in central Arizona. U- basin. This included contributions from arc- basin environments to a stable continental re- Pb ages of zircons from rhyolite ash-¯ow tuff related supracrustal rocks of the Payson gime (Bowring and Karlstrom, 1990; Karls- indicate that deposition began at 1701 6 2 Ophiolite and East Verde River Formation, trom and Bowring, 1988; Karlstrom et al., Ma. Basal deposits of the newly de®ned Pine and ®nally a granitic basement input. Detri- 1987). Information about the age and stratig- Creek Conglomerate formed in an alluvial- tal quartz in the lower part of the Mazatzal raphy of these sedimentary deposits is there- fan setting, synchronous with the ®nal Group is largely monocrystalline, and vol- fore fundamental to understanding the later phase of extrusive rhyolite volcanism and canic in origin.
    [Show full text]
  • Hydrocarbon Reservoir and Source-Rock Characteristics from Selected Areas of Southwestern Alaska
    STATE OF ALASKA DEPARTMENT OF NATURAL RESOURCES HYDROCARBON RESERVOIR AND SOURCE-ROCK CHARACTERISTICS FROM SELECTED AREAS OF SOUTHWESTERN ALASKA BY W.M. Lyle Alaska Division of Geological and Geophysical Surveys and I.F. Palmer, Jr., J.G. Bolm, and T.O. Flett U.S. Minerals Management Service - -- -- - -- -- -- - - - --- -- PROFESSIONAL REPORT 77 Published by DIVISION OF GEOLOGICAL & GEOPHYSICAL SURVEYS ROSS G. SCHAFF STATE GEOLOGIST PROFESSIONAL REPORT 77 HYDROCARBON RESERVOIR AND SOURCE-ROCK CHARACTERISTICS FROM SELECTED AREAS OF SOUTHWESTERN ALASKA BY W.M. Lyle, I.F. Palmer, Jr., J.G. Bolm, and T.O. Flett STATE OF ALASKA Jay S. Hammond, Gouernor John W. Katz, Commissioner, Dept. ofNatural Resources Geoffrey Haynes, Deputy Commissioner Ross G. Schaff, State Geologist For sale by Alaska Division of Geological and Geophysical Surveys, P.O. Box 80007, College, 99708; 323 E. 4th. Anchorage, 99501: P.O. Box 7438, Ketchikan, 99901; and 230 So. Franklin, Juneau, 99811. Price: $6.50. CONTENTS Page Abstract .................................................................... 1 Introduction ................................................................. 1 Structural geology .............................................................. 1 Formal rock units studied ......................................................... 2 GemukGroup.............................................................. 2 KuskokwimGroup .......................................................... 4 Shaktolik Group ...........................................................
    [Show full text]
  • The Formation of Convolute Lamination in Mud‐
    DR. CHARLOTTE GLADSTONE (Orcid ID : 0000-0001-8869-2520) Article type : Original Manuscript The formation of convolute lamination in mud-rich turbidites Gladstone, C.†, McClelland, H.M.O.^, Woodcock, N.H.*, Pritchard, D‡. and Hunt, J.+ †BP Institute for Multiphase Flow, University of Cambridge, Madingley Road, Cambridge CB3 0EZ, UK ^Earth and Planetary Sciences Department, Washington University in St Louis, Campus Box 1169, 1 Brookings Drive, Saint Louis, MO 63130, USA. *Department of Earth Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EQ, UK ‡Department of Mathematics and Statistics, University of Strathclyde, 26 Richmond Street, Glasgow G1 1XH, Scotland +National Oceanography Centre, University of Southampton, Waterfront Campus, European Way, Southampton SO14 3ZH, UK Associate Editor – Jaco Baas ABSTRACT Convolute lamination is a common fold structure within turbidite beds, attributed to the deformation of sediment during or soon after deposition of the host bed. Despite the prevalence of this feature, the formational processes are still not well understood. Possible mechanisms are investigated here through redescription and analysis of convolute lamination from the Aberystwyth Grits Group (Silurian, west Wales, UK), in which ‘convolute bedding’ was first defined. Internal bed structures have been studied in clean coastal exposures and on high-resolution optical scans of cut surfaces. Convolute lamination occurs in intervals 2 to 10 cm thick, spanning the top of the very fine sand Bouma C division through the D division of interlaminated silt and clay. Observed growth geometries confirm that the structure formed during sedimentation of the host graded bed. Folds This is an Accepted Article that has been peer-reviewed and approved for publication in the Sedimentology, but has yet to undergo copy-editing and proof correction.
    [Show full text]
  • By Alyssa Franklin Dykes DEPOSITION, STRATIGRAPHY
    DEPOSITION, STRATIGRAPHY, PROVENANCE, AND RESERVOIR CHARACTERIZATION OF CARBONATE MUDSTONES: THE THREE FORKS FORMATION, WILLISTON BASIN By Alyssa Franklin Dykes A thesis submitted to the Faculty and the Board of Trustees of the Colorado School of Mines in partial fulfillment of the requirements for the degree of Doctor of Philosophy (Geology). Golden, Colorado Date _____________________ Signed: _______________________________ Alyssa Franklin Dykes Signed: _______________________________ Dr. J.F. Sarg Thesis Advisor Signed: _______________________________ Dr. Steve Sonnenberg Thesis Advisor Golden, Colorado Date _____________________ Signed: _______________________________ Dr. Paul Santi Professor and Head Department of Geology and Geological Engineering ii ABSTRACT This thesis uses a drill core database from a 250 square mile area of North Dakota and Montana to evaluate the depositional environment, stratigraphic development, provenance, and reservoir quality of the Famennian Three Forks carbonate mudstones. Depositional environments and lithofacies include the following. Schizohaline, storm dominated intrashelf deposits defined by disturbed claystone, dolomudstone, sandstone, laminated mudstone, and distorted to brecciated dolomudstone lithofacies. These lithofacies often contain syneresis cracks, desiccation cracks, high depositional rate features such as convolute bedding and load features, and many scours. Ichnofacies vary from fairweather mobile and sessile feeding traces, early post-storm event escape traces, post-event opportunistic colonizers, and a final return to fairweather colonies. Arid shallow shelf deposits form during times of minimal fluvial and resultant minimal siliciclastic input into the basin, as well as times of evaporation conducive to broad salina, evaporative gypsum deposits. Mudflats rim these two shelf environments. During arid times they commonly contain abundant syndepositional nodular anhydrites and during less arid times they are full of intraclasts that range in abundance and size.
    [Show full text]