DOCSLIB.ORG

The Age of the Morrison Formation

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
The Age of the Morrison Formation THE AGE OF THE MORRISON FORMATION BART J. KOWALLIS ",*, ERIC H. CHRISTIANSEN ", ALAN L. DEINO b, FRED PETERSONC,CHRISTINE E. TURNER", MICHAEL J. KUNK and JOHN D OBRADOVICH ' " Dcyartnlent of Geology, Briglzunz Young University, Proijo, UT 84602, USA; Berkelej~Ceocl~ronolog~~ Center., 2455 Ridge Road, Berkeley, CA 94709, USA; US Geologiciil Surve.~,Feilercrl Cmter, Denver, CO 80225, USA; US Grological Sclr11ej,,981 Natior~alCenter, Reston, VA 22092, USA IReceii~erlin fi~l~Ifvi.i??4 April 1997) The Morrison Formation in Utah and Colorado contams many volcanic ash layers and ashy beds, now altered rnostly to bentonite, that have yielded isotopic ages. The Brushy Basin Member. at the top of the formation, gives single-crystal. laser-fusion and step-heating, pla- teau 40~r/3'~rages on sanidine that range systematically between 148.1 50.5 (1 std. error of mean) at the top of the nlember to 150.3 rt 0.3 Ma near the bottom. The Tidwell Member, at the base of the Morrison Formation, contaills one ash bed about 3 m above the J-5 unconfor- lnity that occurs in at least two widely separated sections. This ash has been dated by "~r/'~Ardating of saliidi~leand gives ages of 154.75 rt 0.54 Ma (Deino NTM sample, laser- fusion), 154.82 31 0.58 Ma (Demo RAIN sample, laser-fusion), 154.87 !C 0.52 (Kunk NTM sample, plateau). and 154.8 !C 1.4 Ma (Obradovich NTM sample, laser-fusion). The Morrison Formation, therefore, ranges in age fron: about 148 to 155 Ma and, based upon fossll evi- dence appears to be entirely Late Jurassic, including the latest Oxfordian(?). Kimmeridgian, and early Tithonian Ages. Kej.,t'or.rf.~:Morrison Formation; lsotoplc ages; Latest Oxfordian('?); Kimmeridgian; Early Tithonian One of the significant unresolved problems related to the Morrison For- niation is its age. both ~11ronostratigrapl1icallyand biostratigraphically. The for~nationhas been labeled as Jurassic. Cretaceous, and Jurassic- Cretaceous over the years (e.g., Eninions and others, 1896; Darton, 1922; * Corresponding autlior 236 B.J. KOWALI.IS ri tri. Simpsoa, 1926; Stokes, 1944; Imlay, 1952; 1980; Bilbey-Bowman and others; 1986; Hotton, 1986; Kowallis anci others, 1986; Kowallis and Heaton, 1987). In one of the lllost recent papers to address this problem, Kowallis and others (1991) observed that, "Precise ages from the ~~ppermostpart of the Brushy Basin Member are still needed to deteriiiitle if the Jurassic- Cretaceous boundary lies within the uppermost Brushy Basin Meruber." The authors might also have added that very little is known about the age of the lower members of the Morrison Formation. The age data reported in this paper, in addition to those ages reported earlier in Kowallis and others (1991), and in conjuilctio~lwith the biostratigraphic informa- tion reported by Schudack and others (this volume) and Litwin and others (this volume), provide a solid framework for determining the age, both iso- topic and biostratigraphic, of the Morrison Formation. PREVIOUS AGE ASSIGNMENTS Table I lists studies reporting isotopic ages froni the Morrison Formation (most of the previously published ages came fi-om the Brushy Basin Mem- ber), excluding the new ages reported here. These radiometric ages span the Cretaceous-Jurassic bou~idaryaccording to published time scales (e.g., the Jurassic-Cretaceous boundary is given as 130Ma by Kennedy and Odin, 1982; 145.6 Ma by Haslalid and others, 1990; 141.1 Ma by Bralower and others, 1990; and 142Ma by Obradovicli, 1993), and do not resolve longstanding debates concerning the age of the formation (i.e., is the for- mation Jurassic, Cretaceous, or a bit of both?). These previously published isotopic ages have helped to better define the age of the formation, but they all have inlierent problems. The RbbSr age by Lee and Brookiiis (1978) comes fro111 a~~thigenicclay and thus tilust be viewed as a minin~urnage. The K Ar biotite ages are questionable because biotite is aliliost u~iiversally altered to sotile extent in bentonites, and potassium in biotite can be redistributed during alteration of the volcanic ash beds without wffectiag the appearance of the grains. Turner and Fishman (1991) and Christiansen and others (1994) have show11 that potassium was quite mobile during alteration of the Brushy Basin Member ash beds. The fission-track data have 1;rsge errors. include ages on some detrital material, and give several ages that appear to be too young when compared with other methods. The best set of previously published data are the 40~r/"~slases-I'~~si~n plagioclase ages (Kowallis and others. 1991). but plirgioclase has fairly low TABLE I lsotoplc ages from the Morrison For~natioll P Rclc>i'ciic,c, 4go & Ei-1.0,-( i 0) Mnrerinl A4erhod Loculioii & Mernher * 2 Lec and BI-ookiiis. 1978 148+9Ma Clay Rb-Sr New Mexlco (BB) vn Obi-ado\ ich. 19x4 pers. comm. 134i 1.2Ma Biotlte K-Ar Colorado (BB) 3 Bilhrq. 1992 147.2+ 1.0Ma Biotite K-Ar Cleveland-Lloyd Q. (BB) Billx>. 1992 146.8 + 1.OMa Biotite K- Ar Cleveland-Lloyd Q. (BB) 78 Bilbsq. 1992 135.23~5.5 Ma Biotite K-Ar D~nosaurNatl. Moil. (BB) 2 Ko\valli\ and othzrs. 1986 99- 144 + 8 Ma Zircon Fission Track Notom, Utah (BB) KO\\ allis ;\lid Hcaton. 1987 142- 195 + 9 Ma Zii-con Fission Track Notom, Utah (SW) Z Kounllis and Heaton. 1987 157+7Ma Zircon Fission Track Notom. Utah (Ti ";? Ko~allisand Heaton. 1987 145k 13Ma Apatite Fissioii Track Noiom. Utah (BB) 7 Ko\\.allis ~indHeatoil. 1957 132+ IOMa Apatite Fission Track Kotom. Utah (SW) Kowallia and others. 1991 147.6 ?L 0.8 Ma Plagioclase Ar--Ar laser-fusioil Montezuma Creek (BB) F Plagioclase Ar-Ar laser-fusion Moiltezun~aCreek (BBI r! KO\\allis and others. I99 I 147.0 + 0.6 Ma 0 Ko\valIis :\lid ot11e1.c. 199 1 145.2i- 1.2 Ma Plagioclase Ar-Ar laser-fusion Montezuma Creek (BB) 2 I<onaIlis and others. 1991 147.8 * 0.6 Ma Plagioclase Ar-Ar laser-fusioil Montezuina Creek (BB) Ko\~allisand others. 199 1 149.4 & 0.7 Ma Plagioclase Ar--Ar laser-fusion Montezuma Creek (BB) KO~LIIIISiind otllel-s. 1991 152.9 + 1.2 Ma Plagioclase Ar--Ar laser-fusion Dinosaur Nail. Moil. (BB) DeCellr and Burden, 1992 129 f 14 Ma Zircon Fission Track Central W) oming (BB'?) fvlsiilhci-\ .ire RB - Brn\li) Basin. SW = Salt Wash. T= Tlduell 738 B.J. KOWALLIS ei cil levels of potassium, increasing the errors in these ages. In addition, plagio- clase apl.'ears to be more susceptible to alteration in the Morriso~~'ish beds than sanidine. The paleontological data base has also been a source of shifting age as- sign~nentsfor the Morrison Formation. Table 11 lists sigllificant previously published references related to the biostratigraphic age of the Morrison Formation. We have attempted to compile a list of references that is repre- sentative and fairly complete, but we have undoubtedly nlissed some refer- ences because the Morrison literature is quite extensive. These references show that early ia this century the formation was thought to be Jurassic, Cretaceous, or Jurassic-Cretaceous; during the mid-1900s the forination was thought to be definitely Jurassic; whereas most recently the age has again been questioned, with some scientists proposing a Jurassic Cretac- eous age. In addition to the isotopic and paleontological age determinations listed in Tables I and 11, a few papers have been published on the paleomag~letic reversal sequence in the Morrison Formation. Steiner and Helsley (1975a,b), Steiner (1980), and Steiiler and others (1994) observed that the reversal sequence seen in the Morrison Formation correlates "well with the reversal sequence of about the same age [Kimmeridgian], derived from the oldest observed magnetic anomalies in the sea floor." Swierc and Johilson (1990) examined the reversal pattern in the Morrison and Cloverly formations in the Bighorn Basin of Wyoming and inferred a ~naxin~un~of 7 million years of deposition for the Morrison Formation during the Late Jurassic. They also estimated a niinimunl of 15 million years of nondeposi- tion between the Morrison and Cloverly formations. However, the nature and position of the contact between the Morrison and Cloverly forlnations in Wyoming is problenlatic and no reliable isotopic ages have been obtained there. One zircon fission-track age of 129f 14Ma has been reported from central Wyoining by DeCelles and Burden (1992) from sedi- ments they believe to be Cloverly Formation, but which have been pre- viously assigned to the Morrison. Until these probleins are resolved, a chronologic interpretatioil of the Wyoming paleon~agneticdata will be imprecise STRATIGRAPHY The Morrison Formation in the Colorado Plateau consists largely of intcr- bedded conglomerate, sandstone, mudstone, and altered volcanic ash with relatively small amounts of marlstone, limestone, and claystone. The ash TABLE I1 Uiostrat~gi-aphicage information for the Morrison Formation Ref~frrerlce Age Tvpc of E~~i~ii~rrce Emmons and others, Vertebrates s~rn~larto Jurassic forms 1896 elsewhere Marsh, 1896 Jurassic Dmosaurs are like those of European Jurassic Logan, 1900 Jurassic Illvertebrates similar to Jurassic Wealden of Europe Wdrd, 1900 Jurassic Cycadeoid flora is like that of the .Iurassic IZigg\, 1902 Jurass~c Dinosaurs are like thosc of European Jurassic W~lllston,1905 Cretaceous Vertebrates indicate a Cretaceous age Wa~d,1906 Jurassic Cycads like Jurassic forms Lull, I91 I Cret:iceous Fauna like that of Cretaceous Aru~idel Formation, Maryland Berry, 1915 Cretaceous Flora similar to Cretaceous Potomac Group Lee, 1915 Cretaceous Morrison fauna needed more time to evolve than Jurassic Lull. 1915 Cretaceous D~liosaurssilnilar to African (Tendaguru Fm.) Cretaceous forms Osborn, 1915 Cretaceous-Jurassic Kimmeridgian dinosaurs are like Morrison's, but could be Cret.
Load more

Recommended publications
  • (Reptilia: Archosauria) from the Late Triassic of North America
    Journal of Vertebrate Paleontology 20(4):633±636, December 2000 q 2000 by the Society of Vertebrate Paleontology RAPID COMMUNICATION FIRST RECORD OF ERPETOSUCHUS (REPTILIA: ARCHOSAURIA) FROM THE LATE TRIASSIC OF NORTH AMERICA PAUL E. OLSEN1, HANS-DIETER SUES2, and MARK A. NORELL3 1Lamont-Doherty Earth Observatory, Columbia University, Palisades, New York 10964; 2Department of Palaeobiology, Royal Ontario Museum, 100 Queen's Park, Toronto, Ontario, Canada M5S 2C6 and Department of Zoology, University of Toronto, Toronto, Ontario, Canada M5S 3G5; 3Division of Paleontology, American Museum of Natural History, Central Park West at 79th Street, New York, New York 10024 INTRODUCTION time-scales (Gradstein et al., 1995; Kent and Olsen, 1999). Third, Lucas et al. (1998) synonymized Stegomus with Aeto- To date, few skeletal remains of tetrapods have been recov- saurus and considered the latter taxon an index fossil for con- ered from the Norian- to Rhaetian-age continental strata of the tinental strata of early to middle Norian age. As discussed else- Newark Supergroup in eastern North America. It has always where, we regard this as the weakest line of evidence (Sues et been assumed that these red clastic deposits are largely devoid al., 1999). of vertebrate fossils, and thus they have almost never been sys- tematically prospected for such remains. During a geological DESCRIPTION ®eld-trip in March 1995, P.E.O. discovered the partial skull of a small archosaurian reptile in the lower part of the New Haven The fossil from Cheshire is now housed in the collections of Formation (Norian) of the Hartford basin (Newark Supergroup; the American Museum of Natural History, where it is cata- Fig.
    [Show full text]
  • Morrison Formation 37 Cretaceous System 48 Cloverly Formation 48 Sykes Mountain Formation 51 Thermopolis Shale 55 Mowry Shale 56
    THE STRUCTURAL AND STRATIGRAPHIC FRAMEWORK OF THE WARM SPRINGS RANCH AREA, HOT SPRINGS COUNTY, WYOMING By CHRISTOPHER JAY CARSON Bachelor of Science Oklahoma State University 1998 Submitted to the Faculty of the Graduate College of the Oklahoma State University in partial fulfillment of the requirements for the Degree of MASTER OF SCIENCE July, 2000 THE STRUCTURAL AND STRATIGRAPHIC FRAMEWORK OF THE WARM SPRINGS RANCH AREA, HOT SPRINGS COUNTY, WYOMING Thesis Approved: Thesis Advisor ~~L. ... ~. ----'-"'-....D~e~e:.-g-e----- II ACKNOWLEDGEMENTS I wish to express appreciation to my advisor Dr. Arthur Cleaves for providing me with the opportunity to compile this thesis, and his help carrying out the fieldwork portion of the thesis. My sincere appreciation is extended to my advisory committee members: Dr. Stan Paxton, Dr. Gary Stewart, and Mr. David Schmude. I wish to thank Mr. Schmude especially for the great deal of personal effort he put forth toward the completion of this thesis. His efforts included financial, and time contributions, along with invaluable injections of enthusiasm, advice, and friendship. I extend my most sincere thank you to Dr. Burkhard Pohl, The Big Hom Basin Foundation, and the Wyoming Dinosaur Center. Without whose input and financial support this thesis would not have been possible. In conjunction I would like to thank the staff of the Wyoming Dinosaur Center for the great deal of help that I received during my stay in Thermopolis. Finally I wish to thank my friends and family. To my friends who have pursued this process before me, and with me; thank you very much.
    [Show full text]
  • The Jackpile Sandstone Member of the Morrison Formation in West
    TheJackpile Sandstone Member 0f the MorrisonFormation in west-central New Mexico- a formaldefinition byDonald E. jwen,Consulting Geologist, Tulsa, 0K 74152,and Lester J. Walters,Jr. andRonald G. Beck, ARCO Oil and Gas Co., Dallas, IX75221 The JackpileSandstone Member of the uranium mine. The JackpileSandstone is stonelenses Contactswith the underlying Morrison Formation(Upper Jurassic)in west- typically a whitish, crossbeddedsubarkose Brushy BasinMember of the Morrison For- central New Mexico is named here formallv with clay matrix and interbedded, varie- mation may be gradational, scoured, or from a stratotype near the Jackpile-PaguatL gated, pale-greento red, bentonitic mud- interbedded. The Jackpileextends only a short distancesouth of the stratotvDedue R.5W. to truncation along the basal Dakota un- conformity. However, it extendsnortheast to Lamy, north to near Cuba, and a short distancewest and a longer distancenorth- west into the subsurfaceof the San Juan Basin.Thickness of the Jackpileranges from near zero to 300ft (91 m); at the stratotype it is 100 ft (30 m) thick. Crossbeddingin- dicatesa regional easterlypaleocurrent-flow direction for the braided-streamand distal alluvial-fan complexesin which the Jackpile was deposited. Source areas were to the west and southwest,south of Gallup, and in the Mogollon Highlands. Introduction The Jackpile sandstone of economic usage has been employed informally in strati- graphic nomenclature for a distinctive bed in the uppermost part of the Brushy Basin Member of the Morrison Formation in west- central New Mexico since the Jackpile ura- nium body was discovered in that bed dur- ing 1951.The stratigraphic name fackpile has Alsoin this issue Temperatureof.mineralization in Mogollonmining district p.
    [Show full text]
  • 8. Archosaur Phylogeny and the Relationships of the Crocodylia
    8. Archosaur phylogeny and the relationships of the Crocodylia MICHAEL J. BENTON Department of Geology, The Queen's University of Belfast, Belfast, UK JAMES M. CLARK* Department of Anatomy, University of Chicago, Chicago, Illinois, USA Abstract The Archosauria include the living crocodilians and birds, as well as the fossil dinosaurs, pterosaurs, and basal 'thecodontians'. Cladograms of the basal archosaurs and of the crocodylomorphs are given in this paper. There are three primitive archosaur groups, the Proterosuchidae, the Erythrosuchidae, and the Proterochampsidae, which fall outside the crown-group (crocodilian line plus bird line), and these have been defined as plesions to a restricted Archosauria by Gauthier. The Early Triassic Euparkeria may also fall outside this crown-group, or it may lie on the bird line. The crown-group of archosaurs divides into the Ornithosuchia (the 'bird line': Orn- ithosuchidae, Lagosuchidae, Pterosauria, Dinosauria) and the Croco- dylotarsi nov. (the 'crocodilian line': Phytosauridae, Crocodylo- morpha, Stagonolepididae, Rauisuchidae, and Poposauridae). The latter three families may form a clade (Pseudosuchia s.str.), or the Poposauridae may pair off with Crocodylomorpha. The Crocodylomorpha includes all crocodilians, as well as crocodi- lian-like Triassic and Jurassic terrestrial forms. The Crocodyliformes include the traditional 'Protosuchia', 'Mesosuchia', and Eusuchia, and they are defined by a large number of synapomorphies, particularly of the braincase and occipital regions. The 'protosuchians' (mainly Early *Present address: Department of Zoology, Storer Hall, University of California, Davis, Cali- fornia, USA. The Phylogeny and Classification of the Tetrapods, Volume 1: Amphibians, Reptiles, Birds (ed. M.J. Benton), Systematics Association Special Volume 35A . pp. 295-338. Clarendon Press, Oxford, 1988.
    [Show full text]
  • A New Microvertebrate Assemblage from the Mussentuchit
    A new microvertebrate assemblage from the Mussentuchit Member, Cedar Mountain Formation: insights into the paleobiodiversity and paleobiogeography of early Late Cretaceous ecosystems in western North America Haviv M. Avrahami1,2,3, Terry A. Gates1, Andrew B. Heckert3, Peter J. Makovicky4 and Lindsay E. Zanno1,2 1 Department of Biological Sciences, North Carolina State University, Raleigh, NC, USA 2 North Carolina Museum of Natural Sciences, Raleigh, NC, USA 3 Department of Geological and Environmental Sciences, Appalachian State University, Boone, NC, USA 4 Field Museum of Natural History, Chicago, IL, USA ABSTRACT The vertebrate fauna of the Late Cretaceous Mussentuchit Member of the Cedar Mountain Formation has been studied for nearly three decades, yet the fossil-rich unit continues to produce new information about life in western North America approximately 97 million years ago. Here we report on the composition of the Cliffs of Insanity (COI) microvertebrate locality, a newly sampled site containing perhaps one of the densest concentrations of microvertebrate fossils yet discovered in the Mussentuchit Member. The COI locality preserves osteichthyan, lissamphibian, testudinatan, mesoeucrocodylian, dinosaurian, metatherian, and trace fossil remains and is among the most taxonomically rich microvertebrate localities in the Mussentuchit Submitted 30 May 2018 fi fi Accepted 8 October 2018 Member. To better re ne taxonomic identi cations of isolated theropod dinosaur Published 16 November 2018 teeth, we used quantitative analyses of taxonomically comprehensive databases of Corresponding authors theropod tooth measurements, adding new data on theropod tooth morphodiversity in Haviv M. Avrahami, this poorly understood interval. We further provide the first descriptions of [email protected] tyrannosauroid premaxillary teeth and document the earliest North American record of Lindsay E.
    [Show full text]
  • [PDF] Dinosaur Eggshell from the Red Sandstone Group of Tanzania
    Journal of Vertebrate Paleontology 24(2):494±497, June 2004 q 2004 by the Society of Vertebrate Paleontology NOTE DINOSAUR EGGSHELL FROM THE RED SANDSTONE GROUP OF TANZANIA MICHAEL D. GOTTFRIED1, PATRICK M. O'CONNOR2, FRANKIE D. JACKSON3, ERIC M. ROBERTS4, and REMEGIUS CHAMI5, 1Mich- igan State University Museum, East Lansing, Michigan, 48824, [email protected]; 2College of Osteopathic Medicine, Ohio University, Athens, Ohio, 45701; 3Department of Earth Sciences, Montana State University, Bozeman, Montana, 59717; 4Department of Geology and Geophysics, University of Utah, Salt Lake City, Utah, 84112, 5Antiquities Unit, P.O. Box 2280, Dar es Salaam, Tanzania Investigations over the last several decades at Gondwanan Mesozoic Although the age of the Red Sandstone Group is poorly understood (see localities have signi®cantly expanded our knowledge of the diversity Damblon et al., 1998), a Cretaceous age is suggested at this site based and distribution of Southern Hemisphere dinosaurs. These records are on (1) the overall composition of the fauna, which includes titanosaurid? primarily based on skeletal remains, but included among them are in- sauropods and both avian and nonavian theropods, as well as osteo- stances of preserved eggshell, notably from Argentina (e.g., Calvo et glossomorph ®shes, and (2) the possibility that these deposits may be al., 1997; Chiappe et al., 1998) and India (e.g., Khosla and Sahni, 1995). approximately coeval with the Cretaceous dinosaur beds of Malawi (Ja- In general, however, dinosaur eggshell is relatively poorly known from cobs et al., 1990), which lie ca. 200 km southeast of the Mbeya region. Gondwana, and from Africa in particular.
    [Show full text]
  • By HENRY FAIRFIELD OSBORN and CHARL
    VoL. 6, 1920 PALAEONTOLOGY: OSBORN AND MOOK IS RECONSTRUCTION OF THE SKELETON OF THE SAUROPOD DINOSAUR CAMARASA URUS COPE (MOROSA URUS MARSH) By HENRY FAIRFIELD OSBORN AND CHARLES CRAIG MOOK AMERICAN MusEUM or NATURAL HISTORY, NEW YORK CITY Read before the Academy, November 11, 1919 The principles of modern research in vertebrate palaeontology are illustrated in the fifteen years' work resulting in the restoration of the massive sauropod dinosaur known as Camarasaurus, the "chambered saurian.." The animal was found near Canyon City, Colorado, in March, 1877. The first bones were described by Cope, August 23, 1877. The first at- tempted restoration was by Ryder, December 21, 1877. The bones analyzed by this research were found probably to belong to six individuals of Camarasaurus mingled with the remains of some carnivorous dinosaurs, all from the summit of the Morrison formation, now regarded as of Jurassic- Cretaceous age. In these two quarries Cope named nine new genera and fourteen new species of dinosaurs, none of which have found their way into. palaeontologic literature, excepting Camarasaurus. Out of these twenty-three names we unravel three genera, namely: One species of Camarasaurus, identical with Morosaurus Marsh. One species of Amphicaclias, close to Diplodocus Marsh. One species of Epanterias, close to Allosaurus Marsh. The working out of the Camarasaurus skeleton results in both the artica ulated restoration and the restoration of the musculature. The following are the principal characters: The neck is very flexible; anterior vertebrae of the back also freely movable; the division between the latter and the relatively rigid posterior dorsals is sharp.
    [Show full text]
  • Stratigraphic Framework of the Cretaceous Mowry Shale, Frontier
    Chapter 15 Stratigraphic Framework of the Cretaceous Mowry Shale, Frontier Formation and Adjacent Units, Southwestern Wyoming Province, Volume Title Page Wyoming, Colorado, and Utah By Mark A. Kirschbaum and Laura N.R. Roberts Chapter 15 of Petroleum Systems and Geologic Assessment of Oil and Gas in the Southwestern Wyoming Province, Wyoming, Colorado, and Utah By USGS Southwestern Wyoming Province Assessment Team U.S. Geological Survey Digital Data Series DDS–69–D U.S. Department of the Interior U.S. Geological Survey U.S. Department of the Interior Gale A. Norton, Secretary U.S. Geological Survey Charles G. Groat, Director U.S. Geological Survey, Denver, Colorado: Version 1, 2005 For sale by U.S. Geological Survey, Information Services Box 25286, Denver Federal Center Denver, CO 80225 For product and ordering information: World Wide Web: http://www.usgs.gov/pubprod Telephone: 1-888-ASK-USGS For more information on the USGS—the Federal source for science about the Earth, its natural and living resources, natural hazards, and the environment: World Wide Web: http://www.usgs.gov Telephone: 1-888-ASK-USGS Although this report is in the public domain, permission must be secured from the individual copyright owners to reproduce any copyrighted materials contained within this report. 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. Manuscript approved for publication May 10, 2005 ISBN= 0-607-99027-9 Contents Abstract ………………………………………………………………………………………
    [Show full text]
  • This Is a Digital Document from the Collections of the Wyoming Water Resources Data System (WRDS) Library
    This is a digital document from the collections of the Wyoming Water Resources Data System (WRDS) Library. For additional information about this document and the document conversion process, please contact WRDS at [email protected] and include the phrase “Digital Documents” in your subject heading. To view other documents please visit the WRDS Library online at: http://library.wrds.uwyo.edu Mailing Address: Water Resources Data System University of Wyoming, Dept 3943 1000 E University Avenue Laramie, WY 82071 Physical Address: Wyoming Hall, Room 249 University of Wyoming Laramie, WY 82071 Phone: (307) 766-6651 Fax: (307) 766-3785 Funding for WRDS and the creation of this electronic document was provided by the Wyoming Water Development Commission (http://wwdc.state.wy.us) VOLUME 11-A OCCURRENCE AND CHARACTERISTICS OF GROUND WATER IN THE BIGHORN BASIN, WYOMING Robert Libra, Dale Doremus , Craig Goodwin Project Manager Craig Eisen Water Resources Research Institute University of Wyoming Report to U.S. Environmental Protection Agency Contract Number G 008269-791 Project Officer Paul Osborne June, 1981 INTRODUCTION This report is the second of a series of hydrogeologic basin reports that define the occurrence and chemical quality of ground water within Wyoming. Information presented in this report has been obtained from several sources including available U.S. Geological Survey publications, the Wyoming State Engineer's Office, the Wyoming Geological Survey, and the Wyoming Oil and Gas Conservation Commission. The purpose of this report is to provide background information for implementation of the Underground Injection Control Program (UIC). The UIC program, authorized by the Safe Drinking Water Act (P.L.
    [Show full text]
  • Craniofacial Morphology of Simosuchus Clarki (Crocodyliformes: Notosuchia) from the Late Cretaceous of Madagascar
    Society of Vertebrate Paleontology Memoir 10 Journal of Vertebrate Paleontology Volume 30, Supplement to Number 6: 13–98, November 2010 © 2010 by the Society of Vertebrate Paleontology CRANIOFACIAL MORPHOLOGY OF SIMOSUCHUS CLARKI (CROCODYLIFORMES: NOTOSUCHIA) FROM THE LATE CRETACEOUS OF MADAGASCAR NATHAN J. KLEY,*,1 JOSEPH J. W. SERTICH,1 ALAN H. TURNER,1 DAVID W. KRAUSE,1 PATRICK M. O’CONNOR,2 and JUSTIN A. GEORGI3 1Department of Anatomical Sciences, Stony Brook University, Stony Brook, New York, 11794-8081, U.S.A., [email protected]; [email protected]; [email protected]; [email protected]; 2Department of Biomedical Sciences, Ohio University College of Osteopathic Medicine, Athens, Ohio 45701, U.S.A., [email protected]; 3Department of Anatomy, Arizona College of Osteopathic Medicine, Midwestern University, Glendale, Arizona 85308, U.S.A., [email protected] ABSTRACT—Simosuchus clarki is a small, pug-nosed notosuchian crocodyliform from the Late Cretaceous of Madagascar. Originally described on the basis of a single specimen including a remarkably complete and well-preserved skull and lower jaw, S. clarki is now known from five additional specimens that preserve portions of the craniofacial skeleton. Collectively, these six specimens represent all elements of the head skeleton except the stapedes, thus making the craniofacial skeleton of S. clarki one of the best and most completely preserved among all known basal mesoeucrocodylians. In this report, we provide a detailed description of the entire head skeleton of S. clarki, including a portion of the hyobranchial apparatus. The two most complete and well-preserved specimens differ substantially in several size and shape variables (e.g., projections, angulations, and areas of ornamentation), suggestive of sexual dimorphism.
    [Show full text]
  • Stratigraphic Correlation Chart for Western Colorado and Northwestern New Mexico
    New Mexico Geological Society Guidebook, 32nd Field Conference, Western Slope Colorado, 1981 75 STRATIGRAPHIC CORRELATION CHART FOR WESTERN COLORADO AND NORTHWESTERN NEW MEXICO M. E. MacLACHLAN U.S. Geological Survey Denver, Colorado 80225 INTRODUCTION De Chelly Sandstone (or De Chelly Sandstone Member of the The stratigraphic nomenclature applied in various parts of west- Cutler Formation) of the west side of the basin is thought to ern Colorado, northwestern New Mexico, and a small part of east- correlate with the Glorieta Sandstone of the south side of the central Utah is summarized in the accompanying chart (fig. 1). The basin. locations of the areas, indicated by letters, are shown on the index map (fig. 2). Sources of information used in compiling the chart are Cols. B.-C. shown by numbers in brackets beneath the headings for the col- Age determinations on the Hinsdale Formation in parts of the umns. The numbers are keyed to references in an accompanying volcanic field range from 4.7 to 23.4 m.y. on basalts and 4.8 to list. Ages where known are shown by numbers in parentheses in 22.4 m.y. on rhyolites (Lipman, 1975, p. 6, p. 90-100). millions of years after the rock name or in parentheses on the line The early intermediate-composition volcanics and related rocks separating two chronostratigraphic units. include several named units of limited areal extent, but of simi- No Quaternary rocks nor small igneous bodies, such as dikes, lar age and petrology—the West Elk Breccia at Powderhorn; the have been included on this chart.
    [Show full text]
  • Paleopathological Analysis of a Sub-Adult Allosaurus Fragilis (MOR
    Paleopathological analysis of a sub-adult Allosaurus fragilis (MOR 693) from the Upper Jurassic Morrison Formation with multiple injuries and infections by Rebecca Rochelle Laws A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science in Earth Sciences Montana State University © Copyright by Rebecca Rochelle Laws (1996) Abstract: A sub-adult Allosaurus fragilis (Museum of the Rockies specimen number 693 or MOR 693; "Big Al") with nineteen abnormal skeletal elements was discovered in 1991 in the Upper Jurassic Morrison Formation in Big Horn County, Wyoming at what became known as the "Big Al" site. This site is 300 meters northeast of the Howe Quarry, excavated in 1934 by Barnum Brown. The opisthotonic position of the allosaur indicated that rigor mortis occurred before burial. Although the skeleton was found within a fluvially-deposited sandstone, the presence of mud chips in the sandstone matrix and virtual completeness of the skeleton showed that the skeleton was not transported very far, if at all. The specific goals of this study are to: 1) provide a complete description and analysis of the abnormal bones of the sub-adult, male, A. fragilis, 2) develop a better understanding of how the bones of this allosaur reacted to infection and trauma, and 3) contribute to the pathological bone database so that future comparative studies are possible, and the hypothesis that certain abnormalities characterize taxa may be evaluated. The morphology of each of the 19 abnormal bones is described and each disfigurement is classified as to its cause: 5 trauma-induced; 2 infection-induced; 1 trauma- and infection-induced; 4 trauma-induced or aberrant, specific origin unknown; 4 aberrant; and 3 aberrant, specific origin unknown.
    [Show full text]