DOCSLIB.ORG

The Relationship Between the Iridium Anomaly and Palynological Floral Events at Three Cretaceous-Tertiary Boundary Localities in Western Canada

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
The Relationship Between the Iridium Anomaly and Palynological Floral Events at Three Cretaceous-Tertiary Boundary Localities in Western Canada The relationship between the iridium anomaly and palynological floral events at three Cretaceous-Tertiary boundary localities in western Canada JOHN F. LERBEKMO University of Alberta, Department of Geology, Edmonton, Alberta T6G 2E3, Canada ARTHUR R. SWEET Geological Survey of Canada, 3303 33 Street N. W., Calgary, Alberta T2L 2E7, Canada ROBERT M. ST. LOUIS* University of Alberta, Department of Geology, Edmonton, Alberta T6G 2E3, Canada ABSTRACT Snead, 1969; a series of papers by Srivastava, culminating in Srivastava, 1970; Leffingwell, 1971; Tschudy, 1971; Sweet, 1978) concerning the Profiles illustrating the abundance of iridium and the changes in region from Colorado through Montana and into Saskatchewan and the relative abundances of major groups within the palynoflora are Alberta substantiated Stanley's work. Collectively, these papers demon- given for three localities from western Canada. The peak abundance strate that the flora coexisting with the dinosaurian Triceratops fauna (of of iridium ranges from 1.35 to 5.60 ppb and corresponds to the base of late Maastrichtian age; Jeletzky, 1960) is characterized by a diverse suite a coal and to a floral-extinction event at the three localities. Imme- of angiosperm pollen that generally dominates the over-all assemblage. diately above the iridium-peak anomaly, angiosperm pollen is con- The most visually conspicuous taxa in this flora belong to Aquilapollenites, spicuous in the assemblage, in contrast to the fern-spore spike Wodehouseia, and allied angiosperm genera, although they rarely exceed a described for sections in the mid-continental United States and at the few percent in relative abundance. Above beds carrying the Triceratops Morgan Creek locality in south-central Saskatchewan. fauna, a shift occurs to a palynoflora that has a lower diversity and is dominated by gymnosperm pollen. INTRODUCTION Studies of the interval immediately adjacent to the Cretaceous- Tertiary boundary in the mid-continental United States have shown that many species of pollen and spores characteristic of the Maastrichtian land flora terminate their upward range at an iridium anomaly (Orth and others, 1981; Smit and van der Kaars, 1984; Tschudy and others, 1984; Alvarez and others, 1984). The same stratigraphic horizon, combining a floral break and an iridium anomaly, has also been identified in Canada (Jerzy- kiewicz and others, 1984; Sweet and Hills, 1984; Lerbekmo and Coulter, 1985; Jerzykiewicz and Sweet, 1986; Lerbekmo and St. Louis, 1986; Nichols and others, 1986). The purpose of this paper is to present geochemical and palynological profiles for the interval immediately contiguous to the Cretaceous-Tertiary boundary for three sections in western Canada. Each section shows a level of extinctions, a level of entrances, and a sequence of changes in the relative abundances of major groups of taxa similarly related to an anom- alously high iridium concentration. The locations are in the central Rocky Mountain foothills, the Red Deer Valley of Alberta, and southwestern Saskatchewan (Fig. 1). Floral Events at the Cretaceous-Tertiary Boundary The basic palynological criteria for differentiating between Maastrich- tian and lower Paleocene strata in the mid-continental region of North America were established by the pioneer work of Stanley (1965) on floras of the Hell Creek and Fort Union Formations of South Dakota. Subse- quently, a succession of papers (Norton and Hall, 1967,1969; Oltz, 1969; Figure 1. Locality map. C.V. = Coal Valley section; R.D.V. = Red 'Present address: Suburban Resources, 259 Skyline Avenue, Tooele, Utah Deer Valley section; F.V. = Frenchman Valley section. See text for 84074. exact locations. Geological Society of America Bulletin, v. 99, p. 325-330,4 figs., September 1987. Downloaded from http://pubs.geoscienceworld.org/gsa/gsabulletin/article-pdf/99/3/325/3998305/i0016-7606-99-3-325.pdf by guest on 25 September 2021 326 LERBEKMO AND OTHERS The present of Aquilapollenites and allied taxa of the triprojectate EPOCH/ / A. COAL VALLEY B. RED DEER VALLEY C FR VALLEY^ complex identifies the late Maastrichtian flora of the mid-continental inte- ^STAGE rior basin from Wyoming north as belonging to the Aquilapollenites palynofloral province. This palynofloral province was initially considered UJ |iillM j Z , . UJ to have a north-south trend but is now recognized as being essentially (J O PASKAPOO FM. northern circumjiolar with north-south flexuresimpose d by the position of UJ the Late Cretaceous epicontinental seaways (Samoilovich, 1977; RAVENSCRAG FM. Chlonova, 1981; Srivastava, 1981; Batten, 1984). ccALSPU R SCOLLARD The diagnostic angiosperm pollen taxa with the late Maastrichtian — MV MHEER COAlu M NFUI-; rnAi ^ — FFRRIS roai — Aquilapollenites floral province are frequently relatively large and mor- 3 FM. 2 FM- FRENCHMAN FM. phologically complex. Generally, it is these morphologically exotic groups 5•7 OQf f / NTRANCE CGL ° z BATTLE FM. that became extinct at the boundary, resulting in a less diverse early G S 9 WHITEMUDFM. Paleocene palynoflora in which the dominant pollen species are relatively z o small and have reduced sculpture and simple shapes. Because of this, s o HORSESHOE EASTEND FM. distinct phytogeographic provinces are not recognized in the early UJ CANYON Paleocene. SAUNDER FM. a> RAZEAU MAASTRICHT! FM. — N THE CRETACEOUS-TERTIARY BOUNDARY BEARPAW FM. IN WESTERN CANADA OLDMAN FM. JUDITH RIVER FM. The stratigiaphic level of this boundary in Alberta and Saskatche- CAMPANIA wan, as identified palynologically, coincides with the base of the first major coal seam in the section (the Mynheer, Nevis, or Ferris seams; Figure 2. Table of formations. Figs. 2 and 3), which overlies an interval barren of coal but containing a highly diverse Maastrichtian flora. At this level, the uppermost limit of the stratigraphic range of several species terminates and, above it, species not though diversity drops, the relative abundance of angiosperm pollen re- represented in the Maastrichtian make their first appearance. These mains high through at least the lower 7 cm of the Mynheer coal because of changes at the species level correspond to the classic shift from a diverse, a relatively large number of specimens of Syncolporites minimus and angiosperm-dominated, late Maastrichtian flora (within which triprojec- Triporopollenites plektosus. Above this interval, the dominance shifts from tate pollen is especially prominent) to a low-diversity, early Paleocene angiosperm and gymnosperm pollen to miospores (mostly Laevigatospor- flora dominated by gymnosperm pollen and miospores. This is also the ites sp.) and gymnosperm pollen (Taxodiaceae-Cupressaceae complex). level of the peak of anomalously high iridium concentration at the boun- Although several species characteristic of the Maastrichtian have their dary (Fig. 4). uppermost range coinciding with the base of the coal, many species, in- cluding Wodehouseia spinata, Aquilapollenites immiser, and A. reticula- Central Foothills: Luscar-Sterco Mine Site, ta, do persist above the Cretaceous-Tertiary boundary. Coal Valley Area A few different species enter the record near the base of the Paleo- cene. These include Aquilapollenites sp. cf. A. quadrilobus, a thin-walled, The Cretacjous-Tertiary boundary at the central foothills site (sec. finely spinose, heteropolar, triprojectate grain, and Cranwellia subtilis, a 25, T. 47, R. 20 W5 Mer.; GSC Locality No. C-l 11248) lies at the base of small, very finely striate species. The first appearance of Wodehouseia the first thick and laterally persistent coal (Mynheer) overlying a non-coal- fimbriata is in a 20-cm rider seam, the base of which is 1.15 m above the bearing interval, spanning the upper Maastrichtian. No other notable litho- top of the main Mynheer coal zone or ~ 11.3 m above the Cretaceous- logic differences are seen within the Saunders Group below and above the Tertiary boundary. Cretaceous-Tertiary boundary. The initiation of coal deposition in the The iridium anomaly associated with the Cretaceous-Tertiary bound- Coalspur Formation is consistent with the cyclic pattern established within ary at this location occurs in the basal part of the Mynheer coal (Fig. 4 A). the underlying Brazeau Formation. Nevertheless, the thickness and lateral The peak value of 5.6 ± 0.32 ppto occurs in the lowest 1 cm of the coal, but extent of coal zones immediately above the Cretaceous-Tertiary boundary anomalously high values occur through at least the lower 4 cm of the coal far exceed those found in the underlying formation and may in some way and probably through ~7 cm. Only normal background values occur in be related to the Cretaceous-Tertiary boundary event(s) (Jerzykiewicz and the 3-cm mudstone immediately below the coal. The original coal-mud- Sweet, 1986). stone contact was not verifiable in the core, however. The asymmetry of As summarized in Jerzykiewicz and Sweet (1986), the basal 3 cm of the iridium anomaly, especially when compared to the other two localities, the Mynheer coal (Figs. 3A and 4A) can be lithologically described as coal suggests that as much as a few centimetres of sediment may not have been with lenses of light gray, bentonitic mudstone (shown as a coal band and a recovered at the contact between the coal and the underlying mudstone. bentonite band in Fig. 3A). There is no other evidence of a "boundary clay." Overlying the lowest 3-cm interval, there is a 34-cm-thick coal seam Central Alberta Plains: Kniiidsen's Farm Locality, of which the lower 4 cm was sampled separately. Immediately underlying Red Deer Valley the lowest 3-cm interval of the Mynheer coal is a 3-cm-thick, dark gray, silty mudstone below which there is ~ 1.9 m of sandstone. The horizon that is identified playnologically as the boundary in the Figure 3A summarizes the palynological results obtained from the Red Deer Valley (SE% sec. 11, T. 34, R. 22 W4 Mer.; GSC Locality Nos. study of samples from the lower 1.3 m of the Mynheer coal. The C-l 19651 through 69) is within the Scollard Formation, at the base of the Cretaceous-Tertiary boundary is positioned between the base of the Myn- Nevis coal (Sweet and Hills, 1984).
Load more

Recommended publications
  • The Serendipitous Discovery of an Extraterrestrial Iridium Anomaly at the Cretaceous-Palaeogene Boundary in Gubbio and the Rise of a Far-Reaching Theory
    TO L O N O G E I L C A A P I ' T A A T L E I I A Bollettino della Società Paleontologica Italiana, 58 (1), 2019, 77-83. Modena C N O A S S. P. I. The serendipitous discovery of an extraterrestrial iridium anomaly at the Cretaceous-Palaeogene boundary in Gubbio and the rise of a far-reaching theory Alessandro Montanari & Rodolfo Coccioni A. Montanari, Osservatorio Geologico di Coldigioco, Contrada Coldigioco, I-62021 Apiro, Italy; [email protected] R. Coccioni, Dipartimento di Scienze Pure ed Applicate, Università degli Studi di Urbino Carlo Bo, Piazza della Repubblica 13, I-61029 Urbino, Italy; [email protected] KEY WORDS - Alvarez Hypothesis, mass extinctions, paradigm shift, Italy. ABSTRACT - It is not so frequent that in a scientific investigation using a deductive approach, an unforeseen result leads to a new hypothesis, which grows stronger through the same deductive approach of investigation, and eventually becomes a theory leading to a paradigm shift. The theory that a catastrophic impact of an extraterrestrial object, a comet or an asteroid, on the Earth caused a global mass extinction at the end of the Cretaceous Period strongly challenged the Lyellian paradigm of gradualism/uniformitarianism. In the 1980s, a nonconformist theory sprouted from the serendipitous discovery of an iridium anomaly in an inconspicuous clay layer marking the Cretaceous-Palaeogene boundary in the pelagic succession of Gubbio and opened the way to forty years of heated debates and thousands of scientific publications in the most disparate fields of Earth and planetary sciences. With this paper, our intention is to recount the scientific background, which led to the formulation of this theory.
    [Show full text]
  • The Historical Record in the Scaglia Limestone at Gubbio: Magnetic Reversals and the Cretaceous-Tertiary Mass Extinction
    Sedimentology (2009) 56, 137Ð148 doi: 10.1111/j.1365-3091.2008.01010.x The historical record in the Scaglia limestone at Gubbio: magnetic reversals and the Cretaceous-Tertiary mass extinction WALTER ALVAREZ Department of Earth and Planetary Science, University of California, Berkeley, CA 94720-4767, USA (E-mail: [email protected]) ABSTRACT The Scaglia limestone in the Umbria-Marche Apennines, well-exposed in the Gubbio area, offered an unusual opportunity to stratigraphers. It is a deep- water limestone carrying an unparalleled historical record of the Late Cretaceous and Palaeogene, undisturbed by erosional gaps. The Scaglia is a pelagic sediment largely composed of calcareous plankton (calcareous nannofossils and planktonic foraminifera), the best available tool for dating and long-distance correlation. In the 1970s it was recognized that these pelagic limestones carry a record of the reversals of the magnetic field. Abundant planktonic foraminifera made it possible to date the reversals from 80 to 50 Ma, and subsequent studies of related pelagic limestones allowed the micropalaeontological calibration of more than 100 Myr of geomagnetic polarity stratigraphy, from ca 137 to ca 23 Ma. Some parts of the section also contain datable volcanic ash layers, allowing numerical age calibration of the reversal and micropalaeontological time scales. The reversal sequence determined from the Italian pelagic limestones was used to date the marine magnetic anomaly sequence, thus putting ages on the reconstructed maps of continental positions since the breakup of Pangaea. The Gubbio Scaglia also contains an apparently continuous record across the CretaceousÐTertiary boundary, which was thought in the 1970s to be marked everywhere in the world by a hiatus.
    [Show full text]
  • On the Path of Discovery: the Controversy and Science Behind Chicxulub Crater
    ON THE PATH OF DISCOVERY: THE CONTROVERSY AND SCIENCE BEHIND CHICXULUB CRATER A MODE TO FURTHER UNDERSTANDING THE NATURE OF SCIENCE IN GEOLOGY WYATT PETRYSHEN CONTENTS 1 Preface . 3 1. On The Path Of Discovery Act Ⅰ: A Mysterious Ash . 5 Act Ⅱ: An Unchanged Earth. 11 Act Ⅲ: A Smoking Gun. 15 Act Ⅳ: A Union of Evidence. 22 Act Ⅴ: The Epilogue . 29 2. Activity: Finding A Crater . 32 Map 1 . 33 3. Further Readings A Strange Angle . 34 Neutron Activation Analysis . 37 Teaching Notes . 39 4. Acknowledgements . 40 5. Bibliography . 41 PREFACE The below passages are a collection of narratives intended to further the understanding of the nature of science in geology. The main body On the Path of Discovery, brings the reader through a self guided tour of scientists conducting real-world research. Open ended reflection questions occur throughout the 2 narrative to facilitate active discussions and to help develop an understanding in the nature of science. An activity is included to simulate the real-world research tasks conducted for the original scientific discovery. The section Further Readings has been put in place to expand on some of the scientific topics discussed in the case study. The Further Readings are written in a different tone then On the Path of Discovery; their main purpose is to clarify scientific topics. Acknowledgments and a detailed bibliography have also been included in this collection. “I think it's much more interesting to live not knowing than to have answers which might be wrong. I have approximate answers and possible beliefs and different degrees of uncertainty about different things, but I am not absolutely sure of anything and there are many things I don't know anything about,… I don't have to know an answer.
    [Show full text]
  • Ascent of Dinosaurs Linked to an Iridium Anomaly at the Triassic-Jurassic Boundary
    R EPORTS sion, the network ties become less correlated 11. R. Breiger, Social Forces 53, 181 (1974). 17. P. Killworth, H. Bernard, Soc. Networks 1, 159 (1978). as H increases. In the limit of large H, the 12. B. Bolloba«s, Random Graphs (Academic Press, New 18. B. Manneville, The Biology of Business: Decoding the York, 1985). Natural Laws of the Enterprise (Jossey-Bass, San Fran- network becomes essentially a random graph 13. M. Newman, D. Watts, Phys. Rev. E 60, 7332 (1999). cisco, 1999), chap. 5. (regardless of ␣) and the search algorithm 14. J. Kleinberg, Proc. 32nd ACM Symposium on Theory of 19. We thank J. Kleinberg for beneficial discussions. This becomes a random walk. An effective decen- Computing (Association for Computing Machinery, work was funded in part by the National Science New York, 2000). Foundation (grants SES-00-94162 and DMS- tralized search therefore requires a balance 0109086), the Intel Corporation, and the Columbia 15. H. C. White, Social Forces 49, 259 (1970). University Office of Strategic Initiatives. (albeit a highly forgiving one) of categorical 16. H. Bernard, P. Killworth, M. Evans, C. McCarty, G. flexibility and constraint. Shelly, Ethnology 27, 155 (1988). 23 January 2002; accepted 3 April 2002 Finally, by introducing parameter choices that are consistent with Milgram’s experiment (N ϭ 108, p ϭ 0.25) (1), as well as with subsequent empirical findings (z ϭ 300, H ϭ 2) Ascent of Dinosaurs Linked to (17, 16), we can compare the distribution of chain lengths in our model with that of Travers an Iridium Anomaly at the and Milgram (1) for plausible values of ␣ and b.
    [Show full text]
  • K/T Mass Extinction
    Death from Outer Space, Did an Asteroid Impact Wipe out the Dinosaurs? The asteroid Gaspra - 7x7x12 miles A Gallery of Asteroids Was it really an asteroid? We must have multiple working hypotheses! Dinosaurs forgot to board the Ark K/T Boundary 66 MY Age of Dinosaurs Geologic Time Scale K-T extinction record Wyoming The K/T impact clay layer, T Gubbio, Italy. Iridium anomaly first found here. K = Cretaceous K T = Tertiary Iridium anomaly in the K/T rocks at Gubbio, Italy, 20 cm in parts per billion (PPB). K/T 0 boundary 10 cm PPB 0 10 The K/T boundary in New Mexico is marked by the white claystone just above the head of the hammer. Claire Belcher, Geology Department, University of London The white claystone layer marks the K/T boundary The K/T boundary in Spain Known distribution of sites with K/T Iridium anomaly Map of major impact sites in North America The Berringer Crater in Arizona, 50,000 years old. 4000 ft across -- formed by 100 ft meteorite. Why craters are so much larger than the objects that make them. Like shooting a bullet into a soft target. The Manicougan Crater in Quebec,late Triassic in age -- 100 km diameter Gosses Bluff, Australia. Crater age is 142 Ma, but no mass extinction. A 4 km wide asteroid hit America at the end of the Eocene, 35 m.y. ago the Chicxulub Crater Late Cretaceous Paleogeography Gravity anomaly map of Yucatan area 3D representation of gravity anomaly Another representation of the gravity anomaly on the Yucatan Penninsula: the Chicxulub Crater Tektites from the asteroid impact – melted rock Enlargement of a tektite from the Atlantic sea floor Tektites from the K/T boundary in New Jersey Map showing distribution of tektites by size.
    [Show full text]
  • Asteroids and Dinosaurs: Unexpected Twists and an Unfinished Story
    1 Asteroids and dinosaurs: Unexpected twists and an unfinished story Plate tectonics might seem like a routine topic from a 7th grade textbook, but in the 1970s, plate tectonics was cutting-edge science. The theory had only gained widespread acceptance over the previous ten years and subsequently attracted scads of scientists looking to open up new intellectual frontiers. Walter Alvarez was one of them, but his research into plate tectonics was destined to be sidelined. An intriguing observation would eventually lead him, his collaborators, and the rest of science on an intellectual journey across geology, chemistry, paleontology, and atmospheric science—to- Fig. 1. At left, Luis and Walter Alvarez stand by the rock layers near Gubbio, Italy, where unusually high traces of wards solving one of the great mysteries in Earth’s his- iridium were found at the Cretaceous-Tertiary boundary. Was tory: What happened to the dinosaurs (Fig. 1)? this evidence that of an ancient supernova or an ancient asteroid impact? And what, if anything did it have to do with This case study highlights these aspects of the nature the dinosaur extinction? of science: • Science can test hypotheses about events that happened long ago. • Scientific ideas are tested with multiple lines of evidence. • Science relies on communication within a diverse scientific community. • The process of science is non-linear, unpredictable, and ongoing. • Science often investigates problems that require collaboration from those in many different disciplines. From plate tectonics to paleontology One of the key pieces of evidence supporting plate tec- tonic theory was the discovery that rocks on the sea- floor record ancient reversals of the Earth’s magnetic field: as rocks are formed where plates are moving away from one another, they record the current direction of the Earth’s magnetic field, which flip-flops irregularly over very long periods of time (Fig.
    [Show full text]
  • Global Catastrophes in Earth History
    GLOBAL CATASTROPHES IN EARTH HISTORY An Interdisciplinary Conference on Impacts, Volcanism, and Mass Mortality Snowbird, Utah October 20-23, 1988 N89-2 12E7 --?HEW- Sponsored by The Lunar and Planetary Institute and The National Academy of Sciences Abstracts Presented to the Topical Conference Global Catastrophes in Earth History: An Interdisciplinary Conference on Impacts, Volcanism, and Mass Mortality Snowbird, Utah October 20 - 23,1988 Sponsored by Lunar and Planetary Institute and The National Academy of Sciences LPI Contribution No. 673 Compiled in 1988 Lunar and Planetary Institute Material in this volume may be copied without restraint for library, abstract service, educational, or personal research purposes; however, republication of any paper or portion thereof requires the written permission of the authors as well as appropriate acknowledgment of this publication. PREFACE This volume contains abstracts that have been accepted for presentation at the topical conference Global Catastrophes in Earth History: An Interdisciplinary Conference on Impacts, Volcanism and Mass Mortality. The Organizing Committee consisted of Robert Ginsburg, Chairman, University of Miami; Kevin Burke, Lunar and Planetary Institute; Lee M. Hunt, National Research Council; Digby McLaren, University of Ottawa; Thomas Simkin, National Museum of Natural History; Starley L. Thompson, National Center for Atmospheric Research; Karl K. Turekian, Yale University; George W. Wetherill, Carnegie Institution of Washington. Logistics and administrative support were provided by the Projects Ofice at the Lunar and Planetary Institute. This abstract volume was prepared by the Publications Office staff at the Lunar and Planetary Institute. The Lunar and Planetary Institute is operated by the Universities Space Research Association under contract No. NASW-4066 with the National Aeronautics and Space Administration.
    [Show full text]
  • Magnetostratigraphy of a Core from Raton Basin, New Mexico
    Magnetostratigraphyof a core lrom Raton Basin, NewMexico-implications forsynchroneity of CretaceouslTertiary boundary euents by MichaelA. Payne,En<onProduction ResearchCo., Houston, TX, and DonaldL. Wolberg,Paleontologist, and Ailrian Hunf, ResearchAssistant, New Mexico Bureau of Mines and Mineral Resources,Socorro, NM The magneticpolarity stratigraphyof a The Raton Formation may be up to 610 m various proposed Cretaceous-Tertiary 30.5-m(100.l-fQ-long core from the Raton (2,001ft) thick (Ash and Tidwell, L976) and boundaries have proven inconclusive. This Basinin New Mexicohas been obtained. contains the Cretaceous-Tertiary (K-T) situation is unfortunate given the extant pa- The core includesthe palynologicallyde- boundary. Fossilsare poorly representedwith leomagnetic/paleontologic documentation terminedCretaceous-Tertiarv boundarv and the exception of paleobotanicmaterials. Leaf available. However, Orth provided accessto aniridium abundanceanomily. The bound- (100.1-ft) ary is shownto lie in a normalpolarity zone, floras are known from the Trinidad Sand- the 30.5-m Raton core, drilled by asverified by hand samplescollected from stone, the Vermejo Formation, and the Raton Los Alamos Laboratorv, with a demon- the basin,thus placingin gravedoubt the Formation (Brown, 1943).Brown (7943,1962) strated iridium anomaly-at the palynologic validity of a synchronousworldwide ex- consideredthe lower 15m (49ft) of the Raton CretaceourTertiary boundary. Addition- tinction event. Formation, containing the problematic plant ally, samples were taken from surface ex- f.ossl Paleoasterinquirenda Knowlton, to be posures near the town of Raton at the Introduction Cretaceousin age and the upper part Paleo- Cretaceous-Tertiary boundary. Fig. 3 is a cene. Tschudy (1973)located the palynolog- generalized representation of the 30.5-m The Raton Basinis a large sedimentary and ical Cretaceous-Tertiarv boundarv at 81 m (100.1-ft)core showing dominant lithologies structural basin in northeast New Mexico and (266 ft) and 88 m (289 it; above the base of and paleomagnetic sampling intervals.
    [Show full text]
  • Rapid Short-Term Cooling Following the Chicxulub Impact at the Cretaceous–Paleogene Boundary
    Rapid short-term cooling following the Chicxulub impact at the Cretaceous–Paleogene boundary Johan Vellekoopa,1, Appy Sluijsa, Jan Smitb, Stefan Schoutenc,d, Johan W. H. Weijersc,2, Jaap S. Sinninghe Damstéc,d, and Henk Brinkhuisa aMarine Palynology, Department of Earth Sciences, Faculty of Geosciences, Laboratory of Palaeobotany and Palynology, Utrecht University, 3584 CD, Utrecht, The Netherlands; bEventstratigraphy, Sedimentology, Faculty of Earth- and Life Sciences, VU University Amsterdam, 1081 HV, Amsterdam, The Netherlands; cGeochemistry, Department of Earth Sciences, Faculty of Geosciences, Utrecht University, 3584 CD, Utrecht, The Netherlands; and dDepartment of Marine Organic Biogeochemistry, NIOZ Royal Netherlands Institute of Sea Research, 1790 AB, Den Burg, Texel, The Netherlands Edited by Thure E. Cerling, University of Utah, Salt Lake City, UT, and approved April 11, 2014 (received for review October 14, 2013) The mass extinction at the Cretaceous–Paleogene boundary, ∼66 complicated because the traditional proxy carriers for the surface Ma, is thought to be caused by the impact of an asteroid at Chic- ocean conditions, calcareous microfossils, experienced major xulub, present-day Mexico. Although the precise mechanisms that extinction (17). Furthermore, diagenetic alteration is commonly led to this mass extinction remain enigmatic, most postulated sce- noted in postextinction biotic carbonates, inhibiting accurate narios involve a short-lived global cooling, a so-called “impact temperature reconstructions (18). winter” phase. Here we document a major decline in sea surface Among the few sections with potentially sufficient temporal res- temperature during the first months to decades following the im- olution across the K–Pg boundary are the exceptionally well-pre- pact event, using TEX86 paleothermometry of sediments from the served and well-studied outcrops exposed along the Brazos River Brazos River section, Texas.
    [Show full text]
  • The Chicxulub Multi-Ring Impact Crater, Yucatan Carbonate Platform, Gulf of Mexico
    GEOFÍSICA INTERNACIONAL (2011) 50-1: 99-127 REVIEW ARTICLE The Chicxulub multi-ring impact crater, Yucatan carbonate platform, Gulf of Mexico Jaime Urrutia-Fucugauchi*, Antonio Camargo-Zanoguera, Ligia Pérez-Cruz and Guillermo Pérez-Cruz Received: November 16, 2010; accepted: November 23, 2010; published on line: December 17, 2010 Resumen El cráter Chicxulub, parte de un grupo selecto de corteza inferior y manto superior son deformados rasgos geológicos, constituye un laboratorio para y se tiene un levantamiento en la parte central investigar los procesos de formación de cráteres y de la excavación de varias decenas de kilómetros los efectos de impactos en el planeta. Chicxulub es que forma un levantamiento de basamento que uno de tres cráteres complejos multi-anillos docu- caracteriza a estos cráteres complejos. La zona de mentados en el registro terrestre y el impacto es impacto es deformada y fracturada. Los estudios relacionado a los cambios ambientales y climáticos de la dinámica del impacto, formación del cráter, que marcan la frontera Cretácico/Paleógeno (K/Pg) efectos globales de la liberación de energía y ondas y las extinciones masivas de organismos. El cráter, sísmicas y los modelados del comportamiento de localizado en la porción noroeste de la península materiales sujetos a altas presiones y temper- de Yucatán, está cubierto por sedimentos car- aturas forman parte de los problemas en estudio, bonatados y fue identificado inicialmente en los representado retos interesantes en geociencias. estudios dentro del programa de exploración de La capa de eyecta con el material fragmentado Petróleos Mexicanos. En la superficie, evidencias identificada como la capa K/Pg constituye un mar- del cráter sepultado incluyen al anillo de cenotes y cador estratigráfico a escala global, permitiendo rasgos topográficos semi-circulares, los cuales se correlaciones estratigráficas y análisis de procesos asocian a la compactación diferencial de los ma- en la transición del Mesozoico al Cenozoico.
    [Show full text]
  • The Impact at the Cretaceous/Tertiary Boundary
    The Proceedings of the International Conference on Creationism Volume 4 Print Reference: Pages 241-252 Article 18 1998 The Impact at the Cretaceous/Tertiary Boundary Thomas Fritsche Follow this and additional works at: https://digitalcommons.cedarville.edu/icc_proceedings DigitalCommons@Cedarville provides a publication platform for fully open access journals, which means that all articles are available on the Internet to all users immediately upon publication. However, the opinions and sentiments expressed by the authors of articles published in our journals do not necessarily indicate the endorsement or reflect the views of DigitalCommons@Cedarville, the Centennial Library, or Cedarville University and its employees. The authors are solely responsible for the content of their work. Please address questions to [email protected]. Browse the contents of this volume of The Proceedings of the International Conference on Creationism. Recommended Citation Fritsche, Thomas (1998) "The Impact at the Cretaceous/Tertiary Boundary," The Proceedings of the International Conference on Creationism: Vol. 4 , Article 18. Available at: https://digitalcommons.cedarville.edu/icc_proceedings/vol4/iss1/18 THE IMPACT AT THE CRETACEOUSrrERTIARY BOUNDARY THOMAS FRITZSCHE, DR. BAHNHOFSTR. 2 37139 ADELEBSEN - GERMANY KEYWORDS Impact, K-T boundary, catastrophism, mass extinction ABSTRACT The discovery of iridium anomalies in three Cretaceous-Tertiary sections by the Alvarez team in 1980 prompted them to hypothesize an asteroid impact to explain these unusual concentrations. In the following years further evidence provided more support for their hypothesis, but a small minority of scientists are still unconvinced. Since the earth sciences were confronted with the impact hypothesis heated debates about mass extinctions, gradual or extraterrestrial causes, Lyellian uniformitarianism, evolution, and catastrophism got under way.
    [Show full text]
  • Pillmore (1930–2003) D.J
    Memorial to Charles L. “Chuck” Pillmore (1930–2003) D.J. NICHOLS U.S. Geological Survey, Denver Federal Center, Denver, Colorado 80225, USA The geological community lost an outstanding con- tributor late in 2003 when Charles Lee “Chuck” Pillmore died at the age of 73. A scientist of diverse accomplish- ments, his interests ranged from photogrammetry to paleon- tology and from bedrock geology to the impact event at the Cretaceous-Tertiary (K-T) boundary. Chuck Pillmore was born April 7, 1930, in Boulder, Colorado. He grew up in the Boulder and Lafayette area, where the nearby Rocky Mountains must have subtly inspired his love of geology. When he fi rst attended the University of Colorado in Boulder, he began a program in electrical engineering, but his interest in that was short- lived. The fi eld that would become his profession soon attracted him, and he graduated with a degree in geology in 1952. He went on to complete a Master’s degree in geology in 1954, with a thesis on the petrography and petrology of part of Mount Sopris in western Colorado. He began his career with the U.S. Geological Survey (USGS) that same year, and he remained with the USGS nearly 40 years, until retirement in 1993. For Chuck, retirement meant only that he could devote himself to an unencumbered pursuit of geologic research as Scientist Emeritus with the USGS, and some of his most fulfi lling work was conducted during the last ten years of his life. Chuck was a beloved husband, father, and grandfather, as well as a respected and admired colleague.
    [Show full text]