DOCSLIB.ORG

Stratigraphy of the Cambrian and Ordovician Rocks of East-Central Alaska

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Stratigraphy of the Cambrian and Ordovician Rocks of East-Central Alaska Stratigraphy of the Cambrian and Ordovician Rocks of East-Central Alaska GEOLOGICAL SURVEY PROFESSIONAL PAPER 559-A Stratigraphy of the Cambrian and Ordovician Rocks of East-Central Alaska By EARL E. BRABB LOWER PALEOZOIC PALEONTOLOGY AND STRATIGRAPHY OF EAST-CENTRAL ALASKA GEOLOGICAL SURVEY PROFESSIONAL PAPER 559-A Descriptions of four newly named formations of Early Cambrian to Middle Ordovician age^ and their ecological implications; with a list of lower Paleozoic fossil collections UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1967 UNITED STATES DEPARTMENT OF THE INTERIOR STEWART L. UDALL, Secretary GEOLOGICAL SURVEY William T. Pecora, Director For sale by the Superintendent of Documents, U.S. Government Printing Office Washington, D.C. 20402 - Price 30 cents (paper cover) CONTENTS Cambrian and Ordovician rocks Continued Page Abstract.. _ -___--______-_____ Al Unnamed chert, shale, and limestone._____________ A19 Introduction. ________________ 1 Paleotectonic implications.__________________________ 19 Precambrian rocks ____________ 3 Facies and their ecological implications._______________ 19 Tindir Group___________ 3 Early Cambrian._______________________________ 19 Cambrian rocks._____________ Middle Cambrian.._____________________________ 21 Funnel Creek Limestone. __ Late Cambrian and Early Ordovician _____________ 21 Adams Argillite_________ 7 Middle or Late Ordovician_______________________ 23 Cambrian and Ordovician rocks. 9 Hillard Limestone. _______ 9 Summary. _________________________________________ 23 Jones Ridge Limestone. 15 Lower Paleozoic fossil collections from east-central Lower member. ______ 15 Alaska---------._____.____________---_---___-- 23 Upper member. ______ 18 References cited______________--_--_-_-_---_--_____- 30 ILLUSTRATIONS FIGURE 1. Map showing areas of Cambrian and Ordovician rocks in Alaska. __________________________------------ A2 2. Columnar sections-_-_-_-_---___________________________________________-_-_____-_-_----_--------- 4 3. Locality map_________________-_____--__________________-___-_____-_-_---__-__-------_----------_- 6 4-12. Photographs showing 4. Lower Paleozoic sequence along Tatonduk River._____________________-__-----__-_--___-----__ 8 5. Cambrian sequence at east end of Limestone Hogback._______-_________-__--___---_----------- 9 6. Hillard Limestone near Hillard Peak_ ________________________________--_-_-_--__------------ 10 7. Location of measured sections in Adams Peak-Yukon River area._____________________------__-- 11 8. Hillard Limestone and Adams Argillite near Adams Peak____-_--____-_--_--------------_---__- 11 9. Hillard Limestone on ridge and flatiron southwest of Adams Peak_____________________________ 12 10. Limestone edgewise conglomerate- __________________________-___-___-________--------------- 12 11. Limestone boulder conglomerate ledge along Tatonduk River._______________--__-___-__-_-----_ 13 12. Contact between Jones Ridge Limestone and Tindir Group_________________________-_------_- 16 13. Stratigraphic columns of lower Paleozoic formations in east-central Alaska.______________________________ 17 14. Photograph showing upper part of Jones Ridge Limestone....----------------------------------------- 18 15. Lithofacies maps, Early to Late Cambrian___-__-__-______________-_-____-.---_----_----------------- 20 16. Lithofacies maps, Late Cambrian to Middle or Late Ordovician______________--_-__-__-_--__---___-__ 22 in LOWER PALEOZOIC PALEONTOLOGY AO STRATIGRAPHY OF EAST-CENTRAL ALASKA STRATIGRAPHY OF THE CAMBRIAN AND ORDOVIGIAN ROCKS OF EAST-CENTRAL ALASKA By EARL E. BRABB ABSTRACT of Middle and Late Cambrian age are present. Cairnes Four new formational names are herein established for the did not map the Cambrian rocks separately but included westernmost known exposures of Cambrian sedimentary rocks them in an undivided limestone and dolomite unit of in North America. The Funnel Creek Limestone and Adams Cambrian to Devonian age. Mertie (1930) subdivided Argillite of Early Cambrian age and the Hillard Limestone of the rocks of Cambrian and possible Cambrian age into Early Cambrian to Early Ordovician age are key formations in determining the structure and stratigraphy of the Hillard four unnamed formations plus the Tindir Group, and Peak to Hard Luck Creek area, and the largely coeval Jones he (1933) proposed the following classification which Ridge Limestone of Early Cambrian to Middle or Late Ordo­ until now has served as a standard: vician age forms spectacular cliffs and jagged peaks in the Jones Ridge-Squaw Mountain area. Facies maps prepared from meas­ 1. Tindir Group of pre-Middle Cambrian age (probably ured sections of these formations and from fossil determinations Precambrian). suggest that the Jones Ridge-Squaw Mountain area was some 2. Lower plate of Middle Cambrian limestone. sort of shoal or reef during part of the early Paleozoic, and that 3. A thin formation of slate and quartzite, also of Mid­ the Hillard Peak-Hard Luck Creek area was a turbulent marine dle Cambrian age. shelf that received considerable terrigenous material from un­ known sources, and possibly some material from the Jones Ridge- 4. Upper plate of Middle Cambrian limestone. Squaw Mountain shoal. 5. Upper Cambrian limestone which grades upward The area was uplifted, very gently folded, and eroded during without any noticeable straitigraphic or lithologic late Tremadocian or Arenigian (Early Ordovician) time. The break into Ordovician limestone. fold axes apparently trended northeast. Deposition resumed in latest Arenigian or earliest Llanvirnian (Early Ordovician) On his geologic map, Mertie (1933, pi. 7) shows an time in part of the area, and in Caradocian or Ashgillian additional limestone unit of Late Cambrian age which, (Middle or Late Ordovician) time in the Jones Ridge-Squaw for purposes of discussion, is here designated unit 5A. Mountain area. The fossils collected by Mertie were not referred to The rapid changes in facies, the possibility of reeflike sedi­ mentation, and the occurrence of bitumen and other organic his map units but rather to series of the Cambrian, so matter in the rocks make the lower Paleozoic rocks attractive the relative stratigraphic position of these collections for petroleum exploration. is difficult to determine. For example, some of the archaeocyathids reported by Mertie are considered by INTRODUCTION Okulitch (1956, p. 725) to be of Early, not Middle, Undoubted Cambrian fossils in Alaska have been Cambrian age, but the relation of the rocks containing found only in the vicinity of Eagle (fig. 1). The re­ the archaeocyathids to rocks containing definite Middle gional significance of the rocks containing these fossils Cambrian trilobites is uncertain. Moreover, there seems rests largely on their unique geographic position as the to be no lithologic means for distinguishing his units 2, westernmost known exposures of Cambrian sedimentary 4, 5, and 5A. For these reasons, a new set of formations rocks in North America. The Cambrian section of the is established here on the basis of mapping of litho- Eagle area provides a critical link between the Cam­ logically separable units containing stratigraphically brian in southern parts of the Cordilleran geosyncline oriented fossil collections. and that in various parts of Asia and the Arctic. The Cambrian rocks described in this report were Fossils of definite Cambrian age in Alaska were first first examined in 1960 as part of a project to prepare a discovered by Cairnes (1914a) along the international regional geologic map (1:250,000) of the area between boundary in the vicinity of Eagle. L. D. Burling iden­ the Yukon and Porcupine Kivers and the U.S.-Canada tified the fossils for Cairnes and determined that faunas border. Preliminary geologic maps of some of this area Al A2 LOWER PALEOZOIC PALEONTOLOGY AND STRATIGRAPHY OF EAST-CENTRAL ALASKA EXPLANATION Area of predominantly carbonate rocks of Ordovician age Area of predominantly siliceous rocks of Ordovician age Area of known Cambrian and Ordovician rocks Oldhamia, localities where rocks are probably of Cambrian age REFERENCES 1 Steidmann and Cathcart (1922) airbanks 2 Eakin (1918) 3 Brown (1926) L 4 Sainsbury (1965) Big Delta 5 Brooks (1911) 6 Mertie(1937) 7 Churkin and Brabb (1965b) 8 Churkin and Brabb (1965b) 9 Kindle (1908) o 10 Cairnes (1914a, and unpub. data) .. Nabesna 11 Churkin and Brabb (1965b) ^'"""ti.Copper Center ' 12 This report 13 Buddington and Chapin (1929) GULF OF ALASKA OCEAN FIGURE 1. Index map showing areas of Cambrian and Ordovician rocks in Alaska. Prepared by Michael Churkin, Jr. STRATIGRAPHY, CAMBRIAN AND ORDOVICIAN ROCKS A3 have been released as open-file reports of the U.S. Geo­ PRECAMBRIAN ROCKS logical Survey (Brabb and Churkin, 1964,1965). Ap­ TINDIR GROUP proximately 4 days during the summer of 1960 and 6 days during 1961 were spent examining the Cambrian A 5,000- to 25,000-foot-thick succession of limestone, rocks and collecting fossils from them. E. N. Passero dolomite, quartzite, shale, and greenstone along the and H. J. Eoepke in 1960 and J. C. Melik and E. L. Alaska-Yukon Territory boundary between the Yukon Taylor in 1961 assisted in the geologic work. Michael and Porcupine Eivers was named the Tindir Group by Churkin, Jr., geologist, and A. J. Aadland, field assist­ Cairnes (1914a). Mertie (1933) subdivided the Tindir ant, joined the project in May, 1962. During the sum­ Group into seven informal units, and the youngest of mer of 1962 transportation was to have been mainly by these, termed
Load more

Recommended publications
  • On the Continuity of Background and Mass Extinction
    Paleobiology, 29(4), 2003, pp. 455±467 On the continuity of background and mass extinction Steve C. Wang Abstract.ÐDo mass extinctions grade continuously into the background extinctions occurring throughout the history of life, or are they a fundamentally distinct phenomenon that cannot be explained by processes responsible for background extinction? Various criteria have been proposed for addressing this question, including approaches based on physical mechanisms, ecological se- lectivity, and statistical characterizations of extinction intensities. Here I propose a framework de®ning three types of continuity of mass and background extinc- tionsÐcontinuity of cause, continuity of effect, and continuity of magnitude. I test the third type of continuity with a statistical method based on kernel density estimation. Previous statistical ap- proaches typically have examined quantitative characteristics of mass extinctions (such as metrics of extinction intensity) and compared them with the distribution of such characteristics associated with background extinctions. If mass extinctions are outliers, or are separated by a gap from back- ground extinctions, the distinctness of mass extinctions is supported. In this paper I apply Silverman's Critical Bandwidth Test to test for the continuity of mass ex- tinctions by applying kernel density estimation and bootstrap modality testing. The method im- proves on existing work based on searching for gaps in histograms, in that it does not depend on arbitrary choices of parameters (such as bin widths for histograms), and provides a direct estimate of the signi®cance of continuities or gaps in observed extinction intensities. I am thus able to test rigorously whether differences between mass extinctions and background extinctions are statisti- cally signi®cant.
    [Show full text]
  • Church 18.Pdf (1.785Mb)
    Paleontological Contributions Number 18 Efficient Ornamentation in Ordovician Anthaspidellid Sponges Stephen B. Church August 9, 2017 Lawrence, Kansas, USA ISSN 1946-0279 (online) paleo.ku.edu/contributions Ridge-and-trough ornamented outer-wall fragment of the Ordovician anthaspidellid sponge Rugocoelia eganensis Johns, 1994. Paleontological Contributions August 9, 2017 Number 18 EFFICIENT ORNAMENTATION IN ORDOVICIAN ANTHASPIDELLID SPONGES Stephen B. Church Department of Geological Sciences, Brigham Young University, Provo, Utah 84602-3300, [email protected] ABSTRACT Lithistid orchoclad sponges within the family Anthaspidellidae Ulrich in Miller, 1889 include several genera that added ornate features to their outer-wall surfaces during Early Ordovician sponge radiation. Ornamented anthaspidellid sponges commonly constructed annulated or irregularly to regularly spaced transverse ridge-and-trough features on their outer-wall surfaces without proportionately increasing the size of their internal wall or gastral surfaces. This efficient technique of modi- fying only the sponge’s outer surface without enlarging its entire skeletal frame conserved the sponge’s constructional energy while increasing outer-wall surface-to-fluid exposure for greater intake of nutrient bearing currents. Sponges with widely spaced ridge-and-trough ornament dimensions predominated in high-energy settings. Widely spaced ridges and troughs may have given the sponge hydrodynamic benefits in high wave force settings. Ornamented sponges with narrowly spaced ridge-and- trough dimensions are found in high energy paleoenvironments but also occupied moderate to low-energy settings, where their surface-to-fluid exposure per unit area exceeded that of sponges with widely spaced surface ornamentations. Keywords: lithistid sponges, Ordovician radiation, morphological variation, theoretical morphology INTRODUCTION assumed by most anthaspidellids.
    [Show full text]
  • Diversity Partitioning During the Cambrian Radiation
    Diversity partitioning during the Cambrian radiation Lin Naa,1 and Wolfgang Kiesslinga,b aGeoZentrum Nordbayern, Paleobiology and Paleoenvironments, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91054 Erlangen, Germany; and bMuseum für Naturkunde, Leibniz Institute for Research on Evolution and Biodiversity at the Humboldt University Berlin, 10115 Berlin, Germany Edited by Douglas H. Erwin, Smithsonian National Museum of Natural History, Washington, DC, and accepted by the Editorial Board March 10, 2015 (received for review January 2, 2015) The fossil record offers unique insights into the environmental and Results geographic partitioning of biodiversity during global diversifica- Raw gamma diversity exhibits a strong increase in the first three tions. We explored biodiversity patterns during the Cambrian Cambrian stages (informally referred to as early Cambrian in this radiation, the most dramatic radiation in Earth history. We as- work) (Fig. 1A). Gamma diversity dropped in Stage 4 and de- sessed how the overall increase in global diversity was partitioned clined further through the rest of the Cambrian. The pattern is between within-community (alpha) and between-community (beta) robust to sampling standardization (Fig. 1B) and insensitive to components and how beta diversity was partitioned among environ- including or excluding the archaeocyath sponges, which are po- ments and geographic regions. Changes in gamma diversity in the tentially oversplit (16). Alpha and beta diversity increased from Cambrian were chiefly driven by changes in beta diversity. The the Fortunian to Stage 3, and fluctuated erratically through the combined trajectories of alpha and beta diversity during the initial following stages (Fig. 2). Our estimate of alpha (and indirectly diversification suggest low competition and high predation within beta) diversity is based on the number of genera in published communities.
    [Show full text]
  • Smithsonian Miscellaneous Collections Volume 149, Number 7
    SMITHSONIAN MISCELLANEOUS COLLECTIONS VOLUME 149, NUMBER 7 Cfjarlefii IB. anb jMatp "^aux aHalcott 3Re2(earcl) Jfunb SILICIFIED ORDOVICIAN BRACHIOPODS FROM EAST-CENTRAL ALASKA (With 3 Plates) By REUBEN JAMES ROSS, JR. and J. THOMAS DUTRO, JR. U. S. Geological Survey Denver, Colorado, and Washington, D. C. (Publication 4654) CITY OF WASHINGTON PUBLISHED BY THE SMITHSONIAN INSTITUTION MARCH 4, 1966 LIBRARY OF THE AHEftlCAN MUSELfM Of SMITHSONIAN MISCELLANEOUS COLLECTIONS VOLUME 149, NUMBER 7 CJarleg JB. anb iWarj> Vmx OTaUott Ees^earcfi jFunb SILICIFIED ORDOVICIAN BRACHIOPODS FROM EAST-CENTRAL ALASKA (With 3 Plates) By REUBEN JAMES ROSS, JR. and J. THOMAS DUTRO, JR. U. S. Geological Survey Denver, Colorado, and Washington, D. C. (Publication 4654) CITY OF WASHINGTON PUBLISHED BY THE SMITHSONIAN INSTITUTION MARCH 4, 1966 PORT CITY PRESS, INC. BALTIMORE, MD., U. S. A. CONTENTS Page Abstract 1 Introduction 1 Correlation 3 Taxonomic Descriptions 5 Literature Cited 19 Explanation of Plates 21 Cfjarlesf 29. anb iWarp ^aux OTalcott 3^efi!eartf) jFunb SILICIFIED ORDOVICIAN BRACHIOPODS FROM EAST-CENTRAL ALASKA^ By REUBEN JAMES ROSS, JR. and J. THOMAS DUTRO, JR U.S. Geological Survey, Denver, Colo., Washington, D. C. ABSTRACT Silicified brachiopods from the Tatonduk River area, central east- ern Alaska along the Canadian border, are possibly of late Middle or early Late Ordovician age. The assemblage closely resembles one described by Schuchert and Cooper (1930) and Cooper and Kindle (1936) from Perce, Quebec, Canada. Many elements are also pres- ent in the classical Caradoc section of Girvan, Scotland. Species of Dicoelosia, Ptychopleurella, Cyclospira, Ptychoglyptus, Diambania, and Christiania are very like those from Quebec.
    [Show full text]
  • Cambrian Ordovician
    Open File Report LXXVI the shale is also variously colored. Glauconite is generally abundant in the formation. The Eau Claire A Summary of the Stratigraphy of the increases in thickness southward in the Southern Peninsula of Michigan where it becomes much more Southern Peninsula of Michigan * dolomitic. by: The Dresbach sandstone is a fine to medium grained E. J. Baltrusaites, C. K. Clark, G. V. Cohee, R. P. Grant sandstone with well rounded and angular quartz grains. W. A. Kelly, K. K. Landes, G. D. Lindberg and R. B. Thin beds of argillaceous dolomite may occur locally in Newcombe of the Michigan Geological Society * the sandstone. It is about 100 feet thick in the Southern Peninsula of Michigan but is absent in Northern Indiana. The Franconia sandstone is a fine to medium grained Cambrian glauconitic and dolomitic sandstone. It is from 10 to 20 Cambrian rocks in the Southern Peninsula of Michigan feet thick where present in the Southern Peninsula. consist of sandstone, dolomite, and some shale. These * See last page rocks, Lake Superior sandstone, which are of Upper Cambrian age overlie pre-Cambrian rocks and are The Trempealeau is predominantly a buff to light brown divided into the Jacobsville sandstone overlain by the dolomite with a minor amount of sandy, glauconitic Munising. The Munising sandstone at the north is dolomite and dolomitic shale in the basal part. Zones of divided southward into the following formations in sandy dolomite are in the Trempealeau in addition to the ascending order: Mount Simon, Eau Claire, Dresbach basal part. A small amount of chert may be found in and Franconia sandstones overlain by the Trampealeau various places in the formation.
    [Show full text]
  • Chapter 2 Paleozoic Stratigraphy of the Grand Canyon
    CHAPTER 2 PALEOZOIC STRATIGRAPHY OF THE GRAND CANYON PAIGE KERCHER INTRODUCTION The Paleozoic Era of the Phanerozoic Eon is defined as the time between 542 and 251 million years before the present (ICS 2010). The Paleozoic Era began with the evolution of most major animal phyla present today, sparked by the novel adaptation of skeletal hard parts. Organisms continued to diversify throughout the Paleozoic into increasingly adaptive and complex life forms, including the first vertebrates, terrestrial plants and animals, forests and seed plants, reptiles, and flying insects. Vast coal swamps covered much of mid- to low-latitude continental environments in the late Paleozoic as the supercontinent Pangaea began to amalgamate. The hardiest taxa survived the multiple global glaciations and mass extinctions that have come to define major time boundaries of this era. Paleozoic North America existed primarily at mid to low latitudes and experienced multiple major orogenies and continental collisions. For much of the Paleozoic, North America’s southwestern margin ran through Nevada and Arizona – California did not yet exist (Appendix B). The flat-lying Paleozoic rocks of the Grand Canyon, though incomplete, form a record of a continental margin repeatedly inundated and vacated by shallow seas (Appendix A). IMPORTANT STRATIGRAPHIC PRINCIPLES AND CONCEPTS • Principle of Original Horizontality – In most cases, depositional processes produce flat-lying sedimentary layers. Notable exceptions include blanketing ash sheets, and cross-stratification developed on sloped surfaces. • Principle of Superposition – In an undisturbed sequence, older strata lie below younger strata; a package of sedimentary layers youngs upward. • Principle of Lateral Continuity – A layer of sediment extends laterally in all directions until it naturally pinches out or abuts the walls of its confining basin.
    [Show full text]
  • Appendix 3.Pdf
    A Geoconservation perspective on the trace fossil record associated with the end – Ordovician mass extinction and glaciation in the Welsh Basin Item Type Thesis or dissertation Authors Nicholls, Keith H. Citation Nicholls, K. (2019). A Geoconservation perspective on the trace fossil record associated with the end – Ordovician mass extinction and glaciation in the Welsh Basin. (Doctoral dissertation). University of Chester, United Kingdom. Publisher University of Chester Rights Attribution-NonCommercial-NoDerivatives 4.0 International Download date 26/09/2021 02:37:15 Item License http://creativecommons.org/licenses/by-nc-nd/4.0/ Link to Item http://hdl.handle.net/10034/622234 International Chronostratigraphic Chart v2013/01 Erathem / Era System / Period Quaternary Neogene C e n o z o i c Paleogene Cretaceous M e s o z o i c Jurassic M e s o z o i c Jurassic Triassic Permian Carboniferous P a l Devonian e o z o i c P a l Devonian e o z o i c Silurian Ordovician s a n u a F y r Cambrian a n o i t u l o v E s ' i k s w o Ichnogeneric Diversity k p e 0 10 20 30 40 50 60 70 S 1 3 5 7 9 11 13 15 17 19 21 n 23 r e 25 d 27 o 29 M 31 33 35 37 39 T 41 43 i 45 47 m 49 e 51 53 55 57 59 61 63 65 67 69 71 73 75 77 79 81 83 85 87 89 91 93 Number of Ichnogenera (Treatise Part W) Ichnogeneric Diversity 0 10 20 30 40 50 60 70 1 3 5 7 9 11 13 15 17 19 21 n 23 r e 25 d 27 o 29 M 31 33 35 37 39 T 41 43 i 45 47 m 49 e 51 53 55 57 59 61 c i o 63 z 65 o e 67 a l 69 a 71 P 73 75 77 79 81 83 n 85 a i r 87 b 89 m 91 a 93 C Number of Ichnogenera (Treatise Part W)
    [Show full text]
  • Western North Greenland (Laurentia)
    BULLETIN OF THE GEOLOGICAL SOCIETY OF DENMARK · VOL. 69 · 2021 Trilobite fauna of the Telt Bugt Formation (Cambrian Series 2–Miaolingian Series), western North Greenland (Laurentia) JOHN S. PEEL Peel, J.S. 2021. Trilobite fauna of the Telt Bugt Formation (Cambrian Series 2–Mi- aolingian Series), western North Greenland (Laurentia). Bulletin of the Geological Society of Denmark, Vol. 69, pp. 1–33. ISSN 2245-7070. https://doi.org/10.37570/bgsd-2021-69-01 Trilobites dominantly of middle Cambrian (Miaolingian Series, Wuliuan Stage) Geological Society of Denmark age are described from the Telt Bugt Formation of Daugaard-Jensen Land, western https://2dgf.dk North Greenland (Laurentia), which is a correlative of the Cape Wood Formation of Inglefield Land and Ellesmere Island, Nunavut. Four biozones are recognised in Received 6 July 2020 Daugaard-Jensen Land, representing the Delamaran and Topazan regional stages Accepted in revised form of the western USA. The basal Plagiura–Poliella Biozone, with Mexicella cf. robusta, 16 December 2020 Kochiella, Fieldaspis? and Plagiura?, straddles the Cambrian Series 2–Miaolingian Series Published online 20 January 2021 boundary. It is overlain by the Mexicella mexicana Biozone, recognised for the first time in Greenland, with rare specimens of Caborcella arrojosensis. The Glossopleura walcotti © 2021 the authors. Re-use of material is Biozone, with Glossopleura, Clavaspidella and Polypleuraspis, dominates the succes- permitted, provided this work is cited. sion in eastern Daugaard-Jensen Land but is seemingly not represented in the type Creative Commons License CC BY: section in western outcrops, likely reflecting the drastic thinning of the formation https://creativecommons.org/licenses/by/4.0/ towards the north-west.
    [Show full text]
  • PROPERTY of Alabita STATE Geoloclcal Survlfl LBWY
    PROPERTY OF ALABItA STATE GEOLOClCAL SURVLFl LBWY U.S. DEPARTMENT OF THE INTERIOR TO ACCOMPANY MAP 1-1942 U.S. GEOLOGICAL SURVEY GEOLOGIC MAP AND FOLD- AND THRUST-BELT INTERPRETATION OF THE SOUTHEASTERN PART OF THE CHARLEY RlVER QUADRANGLE, EAST-CENTRAL ALASKA By James H. Dover INTRODUCTION The report contains a geologic map and interpretive cross sections (scale 1:100,000, sheets 1 and 2, respectively), This report presents the geologic map evidence for and a small-scale tectonic map showing regional structural the interpretation of the Charley River region as a fold and continuity and trends (scale 1:500,000, fig. sheet 2). thrust belt. Stratigraphic problems bearing on the rigor of 4, The geologic map contains considerable detail this interpretation are briefly reviewed, and some regional compiled from more than 1,000 field stations (fig. 1, tectonic implications of the fold and thrust belt sheet 1). Nearly 85 percent of these stations and their model-including the interaction of the fold and thrust belt included data are recompiled directly from the original field with the Tintina strike-slip fault zone, are also discussed. notes and field sheets (1960-63, 1967-68, 1973) of PREVIOUS WORK Brabb and Churkin. The new data were collected during parts of four field seasons, from 1982 to 1985, and Geologic observations were first made in the Charley involve a total of 25 days of helicopter-supported field River region by pioneering Alaskan geologists such work, concentrated largely in localities where pre-existing as Prindle (1905, 1906, 1913), Kindle (1908), Brooks data were scarce, or in localities judged from previous and Kindle (1908), and Cairnes (1914), but the recon- work to be critical to structural interpretation.
    [Show full text]
  • The Viruan (Middle Ordovician) of Öland
    The Viruan (Middle Ordovician) of Öland By Valdar Jaanusson ABSTRACT.-The stratigraphy and lithology of the Viruan (Middle Ordovician) Iimestones of the bed-rock of Öland are described based on three bares and on field work in the outcrop area. A combined litho- and bio-stratigraphic classification (termed topo-stratigraphic) is introduced for the described sequence. The names of the Estonian stages (Aserian, Lasnamägian, Uhakuan, and Kukrusean) are used as chrono-stratigraphic references instead of the previous Swedish names of the units of stage category (Platyurus, Schroeteri, Crassicauda, and Ludibundus, re­ spectivcly). New topo-stratigraphic divisions are Segerstad Limestone (of Aserian age), Skärlöv, Seby, and Folkeslunda Limestones (of Lasnamägian age), Furudal, Källa, and Persnäs Lime­ stones (of Uhakuan age), and Dalby Limestone (of Kukrusean age in the bed-rock of Öland). The Aserian Lasnamägian topo-stratigraphic divisions have the same lithological characteris­ and tics throughout Öland. The Uhakuan beds are developed as calcilutites (Furudal Limestone) on southern Öland continuing as a tongue (Källa Limestone) on northern Öland. The middle and upper part of the Uhakuan beds of northern Öland consist of calcarenites (Persnäs Limestone) lithologically indistiguishable from the Kukrusean Dalby Limestone which forms the bed-rock only on northern Öland. Within the Segerstad Limestone two zones are distinguished (z. of Angelinoceras latum and z. of Illaenus planifrons).H ouvr ' s zones of Lituites discors, L. lituus, and L. perfectus are of Lasna­ mägian age, and their stratigraphic position and fauna! characteristics are described. Contents Introduction . 207 Methods .............. 209 Classification of the Viruan rocks of Öland 2I2 Historical survey . 2I9 Taxonornie and nomenclatural notes 22I Viruan rocks of northern Öland .
    [Show full text]
  • Lee-Riding-2018.Pdf
    Earth-Science Reviews 181 (2018) 98–121 Contents lists available at ScienceDirect Earth-Science Reviews journal homepage: www.elsevier.com/locate/earscirev Marine oxygenation, lithistid sponges, and the early history of Paleozoic T skeletal reefs ⁎ Jeong-Hyun Leea, , Robert Ridingb a Department of Geology and Earth Environmental Sciences, Chungnam National University, Daejeon 34134, Republic of Korea b Department of Earth and Planetary Sciences, University of Tennessee, Knoxville, TN 37996, USA ARTICLE INFO ABSTRACT Keywords: Microbial carbonates were major components of early Paleozoic reefs until coral-stromatoporoid-bryozoan reefs Cambrian appeared in the mid-Ordovician. Microbial reefs were augmented by archaeocyath sponges for ~15 Myr in the Reef gap early Cambrian, by lithistid sponges for the remaining ~25 Myr of the Cambrian, and then by lithistid, calathiid Dysoxia and pulchrilaminid sponges for the first ~25 Myr of the Ordovician. The factors responsible for mid–late Hypoxia Cambrian microbial-lithistid sponge reef dominance remain unclear. Although oxygen increase appears to have Lithistid sponge-microbial reef significantly contributed to the early Cambrian ‘Explosion’ of marine animal life, it was followed by a prolonged period dominated by ‘greenhouse’ conditions, as sea-level rose and CO2 increased. The mid–late Cambrian was unusually warm, and these elevated temperatures can be expected to have lowered oxygen solubility, and to have promoted widespread thermal stratification resulting in marine dysoxia and hypoxia. Greenhouse condi- tions would also have stimulated carbonate platform development, locally further limiting shallow-water cir- culation. Low marine oxygenation has been linked to episodic extinctions of phytoplankton, trilobites and other metazoans during the mid–late Cambrian.
    [Show full text]
  • Stratigraphy and Structure of the Subsurface Cambrian and Ordovician Carbonates of New York
    DOCUMENT RESUME ED 093 640 SE 017 316 AUTHOR Rickard, Lawrence V. TITLE Stratigraphy and Structure of the Subsurface Cambrian and Ordovician Carbonates of New York. INSTITUTION New York State Education Dept., Albany. PUB DATE 73 NOTE 30p. EDRS PRICE EF-$0.75 HC-$1.85 PLUS POSTAGE DESCRIPTORS Bibliographies; Earth Science; *Geology; Instruction; *Instructional Materials; *Maps; *Paleontology; Science Education IDENTIFIERS New York State Museum and Science Service ABSTRACT This publication presents a description pf 137 wells in New York State and adjacent parts of Pennsylvania. Correlations with surface exposures are established. Maps and cross sections display the thickness, structure, and stratigraphic relationships of the carbonates described. ,A paleogeologic map of New York State at the end of the Early Ordovician is presented. Two distinct series of rocks which comprise the Cambrian and Ordovician carbonates of New York'are described and studied in detail. The monograpil includes an extensive bibliography, several schematic figures and diagrams, and two appendices which give data relevant to the identification of control wells and subsurface data from control wells. (Author/EB) U S. DEPARTMENT OF HEALTH. EDUCATION B WELFARE NATIONAL INSTITUTE OF EDUCATION THIS DOCUMENT HAS BEEN REPRO OUCEO EXACTLY AS RECEIVED FRO': THE PERSON OR ORGANIZATION ORIGIN ATING IT POINTS OF VIEW OR OPINIONS STATED DO NOT NECESSARILY REPRE SENT OFFICIAL NATIONAL INSTITUTE DI EDUCATION POSITION OR POLICY Stratigraphy and Structure of .the', Subsurface Cambrian OrdoVician arbonates of New York LAWRENCE V. RICKARD NEW YORK STATE MUSEUM AND SCIENCE SERVICE MAP AND CHART SERIES NUMBER 18 The Ulu:Trill) of the Slate of New .York The Stale Education Department Albany, 1973 THE UNIVERSITY OF THE STATE OF NEW YORK Regents of the University (with years when terms expire) 1984 JOSEPH W.
    [Show full text]