DOCSLIB.ORG

Interplay of Oceanographic and Paleoclimate Events with Tectonism During Middle to Late Miocene Sedimentation Across the Southwestern USA

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Interplay of Oceanographic and Paleoclimate Events with Tectonism During Middle to Late Miocene Sedimentation Across the Southwestern USA Interplay of oceanographic and paleoclimate events with tectonism during middle to late Miocene sedimentation across the southwestern USA Charles E. Chapin New Mexico Bureau of Geology and Mineral Resources, New Mexico Institute of Mining and Technology, Socorro, New Mexico 87801, USA ABSTRACT INTRODUCTION Miocene (ca. 27–16 Ma) and is refl ected in the unconformities and missing time- stratigraphic Continental sedimentation refl ects a com- The southwestern United States hosts exten- intervals (lacunas) beneath the Ogallala For- plex interplay of tectonics and climate. A sive continental sedimentary deposits of middle mation on the east fl ank of the Southern Rocky 2000-km transect from coastal California to and late Miocene age between the western Great Mountains and the Fence Lake and Bidahochi the western Great Plains documents a major Plains and the coast of California (Fig. 1). The formations on the west fl ank. Cather et al. increase in sedimentation (ca. 16–6 Ma) deposits occur within several physiographic (2007) document ~1230 m of exhumation of the coeval with deposition of the hemipelagic provinces and at variable elevations and tectonic southeastern Colorado Plateau between eolian Monterey Formation along the California settings. Deposition occurred mainly between accumulation of the Chuska erg (ca. 33.5– coast. Basin and Range-style regional exten- 16 and 6 Ma (Fig. 2), coeval with deposition 27 Ma) and deposition of the Bidahochi Forma- sion following elongation of the Pacifi c– of the hemipelagic Monterey Formation (Ingle, tion (16–6 Ma). Similar exhumation (~1500 m) North American transform boundary at 1981; Behl, 1999) along the California coast and timing (ca. 28–16 Ma) were obtained by ca. 17.5 Ma provided fault-bounded basins (Figs. 1 and 2). In several areas, the deposits Flowers et al. (2008) from (U-Th)/He thermo- for accommodation space, but sedimenta- accumulated following long intervals of erosion chronometry. This exhumation began during tion also occurred on unextended erosional and/or nondeposition (Fig. 2). The middle to late the peak of middle Tertiary ignimbrite volca- surfaces of the Great Plains and Colorado Miocene interval of continental sedimentation nism and supports the interpretations of Roy Plateau. Two global climate transitions ended between ca. 6 and 5 Ma, as integration et al. (2004) and Eaton (2008) of magmati- bracket this sedimentary interval. The of drainages brought about widespread incision, cally driven middle Tertiary uplift. The second middle Miocene transition (ca. 17–12 Ma) exhumation, and deposition of contrasting fl u- period of exhumation began in late Miocene records the global change from equatorial to vial deposits of exterior drainages (Eberly and (ca. 7–6 Ma) and is interpreted herein as result- meridional circulation caused by: (1) closing Stanley, 1978; Scarborough, 1989; Spencer et ing from intensifi cation of the North American of the eastern Tethys Seaway (ca. 18 Ma); al., 2001a; Connell, 2004; Mack, 2004; Smith, monsoon and integration of drainage systems (2) opening of the Arctic–North Atlantic 2004, Polyak et al., 2008). that largely ended accumulation of closed-basin connection (ca. 17.5 Ma); (3) growth of Tectonic events affecting middle and late continental deposits. Thus, the two periods of the East Antarctic Ice Sheet (ca. 14 Ma); Miocene sedimentation and erosion across the exhumation illustrated in Figure 2 document and (4) closing of the Indonesian Seaway Southwest were mainly of two types: (1) those both middle Tertiary tectono-magmatic–driven (ca. 12 Ma). Upwelling of cold waters along that resulted in accommodation space for aggra- uplift and late Miocene–Pliocene climatically the California coast, abetted by domina- dation of sedimentary deposits, and (2) those driven exhumation. tion of La Niña phases of El Niño–Southern that changed oceanic and atmospheric circula- The Miocene record of continental sedimen- Oscillation (ENSO), progressively aridifi ed tion, which affected both climate and sedimen- tation and erosion has traditionally been inter- the Southwest as refl ected in sedimentary tation. A correlation chart that summarizes tec- preted in terms of tectonic or epeirogenic uplift and biologic records. The second climate tonic events, oceanic and atmospheric changes, (for example, Trimble, 1980; Steven et al., 1997; transition occurred as opening of the Gulf of and various sedimentation and climatic effects Eaton, 1987, 2008) with little regard to possible California (ca. 6 Ma) intensifi ed the North in a temporal framework is presented as Fig- climatic effects (Molnar and England, 1990; American monsoon, resulting in integration ure 3. The timing of events is based on compila- Molnar, 2004). Since climate is determined of drainages, incision of uplifts, and exhu- tion of published dates of various types from the mainly by coupling of oceanic and atmospheric mation of basin fi lls. The Miocene ended literature. Ages and descriptions of stratigraphic circulation, I burrowed into the oceanographic with the driest climate of the Tertiary (both units are summarized in Appendix 1, with the literature seeking tectonic, oceanographic, and regional and global) accompanied by con- key references. paleoclimate events that had the appropriate version of savanna to steppe or scrub desert, Figures 2 and 3 show two periods of exhu- timing, scale, and location to have infl uenced the spread of C4 grasses, and the greatest mam- mation that affected the Southern Rocky Moun- Miocene sedimentation and erosion history of mal extinction of the Neogene. tains. The fi rst occurred in Oligocene to middle the southwestern USA. Two climate transitions Geosphere; December 2008; v. 4; no. 6; p. 976–991; doi: 10.1130/GES00171.1; 4 fi gures. 976 For permission to copy, contact [email protected] © 2008 Geological Society of America Downloaded from http://pubs.geoscienceworld.org/gsa/geosphere/article-pdf/4/6/976/3337163/i1553-040X-4-6-976.pdf by guest on 27 September 2021 Miocene sedimentation and climate 125°W 120° 115° 110° 105° 100° W GM NE ID 40° N CB SV OG WY 35 BP NP MP 30 25 GB GS D HP SF M 20 35 CR NV CA UT SL 40 OG M CO KS AZ NM 35° N VR GC R OK B DS LV RGR 45 CP ES O SV RL 30 SB BS SF M V B A LA HP F 50 L S P R Pl W OG ME RG SP T HR BA EP 25 SC ° TX 30 N GOC ME 55 RG 0 500 KM Figure 1. Shaded relief map of the southwestern United States from the western Great Plains on the right (east) to the Pacifi c Coast of California at far left. Northern Gulf of California and Baja Peninsula at lower left. The Southern Rocky Mountains, Rio Grande rift, and Colorado Plateau make up the high topography at center. Selected middle and upper Miocene terrestrial sedimentary deposits (red) were compiled from numerous sources cited in text and Appendix 1. Miocene basins in the Basin and Range province of Arizona and southwest- ern New Mexico are partly obscured by widespread gravel-covered pediments and Pliocene-Quaternary alluvial deposits. Only basins with published Miocene surface or subsurface stratigraphic data are shown. Exposures in Arizona are from Scarborough (1989) and those in southwestern New Mexico modifi ed from Wilks (2005). Monterey Formation and equivalent Miocene deposits of onshore California are shown in blue (from Graham and Williams, 1985, and Williams, 1988). Blue contour lines show the percentage of annual precipitation pro- vided by the North American Monsoon in July, August, and September for the 26-yr period 1963–1988 (from Higgins et al., 1999). Names of states are abbreviated inside their boundaries. A—Albuquerque, B—Bakersfi eld, B—Bidahochi Formation, BA—Baja California, BP—Browns Park Formation, BS—Barstow (Town and Formation), CB—Circle Bar basin, CP—Colorado Plateau, CR—Colorado River, D—Denver, DS—Dove Spring Formation, EP—El Paso, F—Fence Lake Formation, GB—Great Basin, GC—Grand Canyon, GOC—Gulf of California, GM—Granite Mountains basin, GS—Glenwood Springs, HP—High Plains, HR—Hatch–Rincon basin, LA—Los Angeles, LV—Las Vegas, M—Monterey Formation, ME—Mexico, MP—Middle Park, N—North Park, O—Ocate volcanic fi eld, OG—Ogallala Formation, P—Phoenix, PI—Picacho basin, R—Raton, R—Reserve graben, RG—Rio Grande, RGR—Rio Grande rift, S—Socorro, SB— Santa Barbara, SC—Sonoita Creek basin, SF—San Francisco, SF—Santa Fe, SL—San Luis Basin, SP—San Pedro trough, SV—Saratoga Valley, SV—Shadow Valley basin, T—Tucson, V—Verde Basin, VR—Virgin River depression, W—Winston graben. Base from U.S. Geo- logical Survey Shaded Relief Map, R.E. Harrison, 1969, scale 1:7,500,000. Underlined abbreviations used only to distinguish between localities with similar spelling. Geosphere, December 2008 977 Downloaded from http://pubs.geoscienceworld.org/gsa/geosphere/article-pdf/4/6/976/3337163/i1553-040X-4-6-976.pdf by guest on 27 September 2021 on 27 September 2021 by guest Downloaded from http://pubs.geoscienceworld.org/gsa/geosphere/article-pdf/4/6/976/3337163/i1553-040X-4-6-976.pdf 978 Geosphere, December2008 W ~2000 km E Ma MONTEREY MOJAVE LAKE SOUTHERN FENCE BIDAHOCHI SOUTHERN N. & C. RIO OGALLALA OGALLALA Ma 0 FM DESERT MEAD ARIZONA LAKE FM FM NEW MEXICOGRANDE RIFT S. PLAINS N. PLAINS 0 INTEGRATION OF DRAINAGE ca. 6–3 Ma 5 5 10 S. 10 OGALLALA FM FM FM SHADOW V. DOVE SPG. N. MULTI FMS MULTI MONTEREY MULTI FMS MULTI BIDAHOCHI FENCE LAKE MULTI FMS MULTI OGALLALA 15 15 Chapin BARSTOW MULTI FMS MULTI LACUNA PLATE 20 BOUNDARY LACUNA EARLY 20 BASINS RAINBOW LACUNA GARDENS RIFT MEMBER LACUNA DETACHMENT TERRANES BASINS EARLY DETACHMENT TERRANES RIFT AND MESOZOIC MESOZOIC 25 BASINS VOLCANIC 25 and to MESOZOIC AND and ROCKS PERMIAN OLIGOCENE VOLCANIC ARIKAREE GROUP ROCKS ROCKS PERMIAN ROCKS ROCKS MESOZOIC and WHITE 30 R.
Load more

Recommended publications
  • Summary of the Paleontology of the Santa Fe Group (Mio-Pliocene), North-Central New Mexico Barry S
    New Mexico Geological Society Downloaded from: http://nmgs.nmt.edu/publications/guidebooks/30 Summary of the paleontology of the Santa Fe Group (Mio-Pliocene), north-central New Mexico Barry S. Kues and Spencer G. Lucas, 1979, pp. 237-241 in: Santa Fe Country, Ingersoll, R. V. ; Woodward, L. A.; James, H. L.; [eds.], New Mexico Geological Society 30th Annual Fall Field Conference Guidebook, 310 p. This is one of many related papers that were included in the 1979 NMGS Fall Field Conference Guidebook. Annual NMGS Fall Field Conference Guidebooks Every fall since 1950, the New Mexico Geological Society (NMGS) has held an annual Fall Field Conference that explores some region of New Mexico (or surrounding states). Always well attended, these conferences provide a guidebook to participants. Besides detailed road logs, the guidebooks contain many well written, edited, and peer-reviewed geoscience papers. These books have set the national standard for geologic guidebooks and are an essential geologic reference for anyone working in or around New Mexico. Free Downloads NMGS has decided to make peer-reviewed papers from our Fall Field Conference guidebooks available for free download. Non-members will have access to guidebook papers two years after publication. Members have access to all papers. This is in keeping with our mission of promoting interest, research, and cooperation regarding geology in New Mexico. However, guidebook sales represent a significant proportion of our operating budget. Therefore, only research papers are available for download. Road logs, mini-papers, maps, stratigraphic charts, and other selected content are available only in the printed guidebooks. Copyright Information Publications of the New Mexico Geological Society, printed and electronic, are protected by the copyright laws of the United States.
    [Show full text]
  • Carnivora from the Late Miocene Love Bone Bed of Florida
    Bull. Fla. Mus. Nat. Hist. (2005) 45(4): 413-434 413 CARNIVORA FROM THE LATE MIOCENE LOVE BONE BED OF FLORIDA Jon A. Baskin1 Eleven genera and twelve species of Carnivora are known from the late Miocene Love Bone Bed Local Fauna, Alachua County, Florida. Taxa from there described in detail for the first time include the canid cf. Urocyon sp., the hemicyonine ursid cf. Plithocyon sp., and the mustelids Leptarctus webbi n. sp., Hoplictis sp., and ?Sthenictis near ?S. lacota. Postcrania of the nimravid Barbourofelis indicate that it had a subdigitigrade posture and most likely stalked and ambushed its prey in dense cover. The postcranial morphology of Nimravides (Felidae) is most similar to the jaguar, Panthera onca. The carnivorans strongly support a latest Clarendonian age assignment for the Love Bone Bed. Although the Love Bone Bed local fauna does show some evidence of endemism at the species level, it demonstrates that by the late Clarendonian, Florida had become part of the Clarendonian chronofauna of the midcontinent, in contrast to the higher endemism present in the early Miocene and in the later Miocene and Pliocene of Florida. Key Words: Carnivora; Miocene; Clarendonian; Florida; Love Bone Bed; Leptarctus webbi n. sp. INTRODUCTION can Museum of Natural History, New York; F:AM, Frick The Love Bone Bed Local Fauna, Alachua County, fossil mammal collection, part of the AMNH; UF, Florida Florida, has produced the largest and most diverse late Museum of Natural History, University of Florida. Miocene vertebrate fauna known from eastern North All measurements are in millimeters. The follow- America, including 43 species of mammals (Webb et al.
    [Show full text]
  • Pamphlet to Accompany Geologic Map of the Apache Canyon 7.5
    GEOLOGIC MAP AND DIGITAL DATABASE OF THE APACHE CANYON 7.5’ QUADRANGLE, VENTURA AND KERN COUNTIES, CALIFORNIA By Paul Stone1 Digital preparation by P.M. Cossette2 Pamphlet to accompany: Open-File Report 00-359 Version 1.0 2000 This report is preliminary and has not been reviewed for conformity with U. S. Geological Survey editorial standards. Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U. S. Government. This database, identified as "Geologic map and digital database of the Apache Canyon 7.5’ quadrangle, Ventura and Kern Counties, California," has been approved for release and publication by the Director of the USGS. Although this database has been reviewed and is substantially complete, the USGS reserves the right to revise the data pursuant to further analysis and review. This database is released on condition that neither the USGS nor the U. S. Government may be held liable for any damages resulting from its use. U.S. Geological Survey 1 345 Middlefield Road, Menlo Park, CA 94025 2 West 904 Riverside Avenue, Spokane, WA 99201 1 CONTENTS Geologic Explanation............................................................................................................. 3 Introduction................................................................................................................................. 3 Stratigraphy................................................................................................................................ 4 Structure ....................................................................................................................................
    [Show full text]
  • Ground-Water Geochemistry of the Albuquerque-Belen Basin, Central New Mexico
    GROUND-WA TER GEOCHEMISTRY OF THE ALBVQVERQVE-BELEN BASIN, CENTRAL NEW MEXICO By Scott K. Anderholm U.S. GEOLOGICAL SURVEY Water-Resources Investigations Report 86-4094 Albuquerque, New Mexico 1988 DEPARTMENT OF THE INTERIOR DONALD PAUL MODEL, Secretary U.S. GEOLOGICAL SURVEY Dallas L. Peck, Director For additional information Copies of this report can write to: be purchased from: District Chief U.S. Geological Survey U.S. Geological Survey Water Resources Division Books and Open-File Reports Pinetree Office Park Federal Center, Building 810 4501 Indian School Rd. NE, Suite 200 Box 25425 Albuquerque, New Mexico 87110 Denver, Colorado 80225 CONTENTS Page Abstract ............................................................. 1 Introduction ......................................................... 2 Acknowledgments ................................................. 4 Purpose and scope ............................................... 4 Location ........................................................ 4 Climate ......................................................... 6 Previous investigations ......................................... 6 Geology .................................................... 6 Hydrology .................................................. 6 Well-numbering system ........................................... 9 Geology .............................................................. 10 Precambrian rocks ............................................... 10 Paleozoic rocks ................................................. 10 Mesozoic
    [Show full text]
  • Mammal Footprints from the Miocene-Pliocene Ogallala
    Mammalfootprints from the Miocene-Pliocene Ogallala Formation, easternNew Mexico by ThomasE. Williamsonand SpencerG. Lucas, New Mexico Museum of Natural History and Science,1801 Mountain Road NW Albuquerque, New Mexico 87104-7375 Abstract well-develooed mudcracks. The track- ways are diveloped on the mudstone Mammal trackways preserved in the drape but are preserved as infillings at the Miocene-Pliocene Ogallala Formation of base of the overlying conglomerate (Figs. eastern New Mexico represent the first 2-4). Most tracks are preserved on the report of mammal fossils-from this unit in underside of a single, thick conglomerate New Mexico. These trackwavs are Dre- block (Fig. 3). A few isolated mammal served as infillings in a conglomerate near the base of the Ogallala Formation. At least prints were also observed on the under- four mammalian ichnotaxa are represented, side of adjacent blocks.he depth of the including a single trackway of a large camel infillings suggest that tracks were made in (Gambapessp. A), several prints of an uncer- a relatively soft substrate. Some prints are tain family of artiodactyl (Gambapessp B), a accompanied by marks indicating slip- single trackway of a large feloid carnivoran page on a slick, wet substrate (Fig. 5C). (Bestiopeda sp.), and several indistinct im- Infillings of mudcracks and narrow, cylin- pressions, probably representing more than drical burrows and raindrop impressions one trackway of a small canid carnivoran are Dreserved over some areas of the (Chelipus sp ). The footprints are preserved in a channel-margin facies of an Ogallala tracliway slab. Mammal trackways repre- braided stream. sent at least four ichnotaxa.
    [Show full text]
  • Mammalia, Felidae, Canidae, and Mustelidae) from the Earliest Hemphillian Screw Bean Local Fauna, Big Bend National Park, Brewster County, Texas
    Chapter 9 Carnivora (Mammalia, Felidae, Canidae, and Mustelidae) From the Earliest Hemphillian Screw Bean Local Fauna, Big Bend National Park, Brewster County, Texas MARGARET SKEELS STEVENS1 AND JAMES BOWIE STEVENS2 ABSTRACT The Screw Bean Local Fauna is the earliest Hemphillian fauna of the southwestern United States. The fossil remains occur in all parts of the informal Banta Shut-in formation, nowhere very fossiliferous. The formation is informally subdivided on the basis of stepwise ®ning and slowing deposition into Lower (least fossiliferous), Middle, and Red clay members, succeeded by the valley-®lling, Bench member (most fossiliferous). Identi®ed Carnivora include: cf. Pseudaelurus sp. and cf. Nimravides catocopis, medium and large extinct cats; Epicyon haydeni, large borophagine dog; Vulpes sp., small fox; cf. Eucyon sp., extinct primitive canine; Buisnictis chisoensis, n. sp., extinct skunk; and Martes sp., marten. B. chisoensis may be allied with Spilogale on the basis of mastoid specialization. Some of the Screw Bean taxa are late survivors of the Clarendonian Chronofauna, which extended through most or all of the early Hemphillian. The early early Hemphillian, late Miocene age attributed to the fauna is based on the Screw Bean assemblage postdating or- eodont and predating North American edentate occurrences, on lack of de®ning Hemphillian taxa, and on stage of evolution. INTRODUCTION southwestern North America, and ®ll a pa- leobiogeographic gap. In Trans-Pecos Texas NAMING AND IMPORTANCE OF THE SCREW and adjacent Chihuahua and Coahuila, Mex- BEAN LOCAL FAUNA: The name ``Screw Bean ico, they provide an age determination for Local Fauna,'' Banta Shut-in formation, postvolcanic (,18±20 Ma; Henry et al., Trans-Pecos Texas (®g.
    [Show full text]
  • Tertiary Stratigraphy of the Navajo Country Charles A
    New Mexico Geological Society Downloaded from: http://nmgs.nmt.edu/publications/guidebooks/9 Tertiary stratigraphy of the Navajo country Charles A. Repenning, J. F. Lance, and J. H. Irwin, 1958, pp. 123-129 in: Black Mesa Basin (Northeastern Arizona), Anderson, R. Y.; Harshbarger, J. W.; [eds.], New Mexico Geological Society 9th Annual Fall Field Conference Guidebook, 205 p. This is one of many related papers that were included in the 1958 NMGS Fall Field Conference Guidebook. Annual NMGS Fall Field Conference Guidebooks Every fall since 1950, the New Mexico Geological Society (NMGS) has held an annual Fall Field Conference that explores some region of New Mexico (or surrounding states). Always well attended, these conferences provide a guidebook to participants. Besides detailed road logs, the guidebooks contain many well written, edited, and peer-reviewed geoscience papers. These books have set the national standard for geologic guidebooks and are an essential geologic reference for anyone working in or around New Mexico. Free Downloads NMGS has decided to make peer-reviewed papers from our Fall Field Conference guidebooks available for free download. Non-members will have access to guidebook papers two years after publication. Members have access to all papers. This is in keeping with our mission of promoting interest, research, and cooperation regarding geology in New Mexico. However, guidebook sales represent a significant proportion of our operating budget. Therefore, only research papers are available for download. Road logs, mini-papers, maps, stratigraphic charts, and other selected content are available only in the printed guidebooks. Copyright Information Publications of the New Mexico Geological Society, printed and electronic, are protected by the copyright laws of the United States.
    [Show full text]
  • 71St Annual Meeting Society of Vertebrate Paleontology Paris Las Vegas Las Vegas, Nevada, USA November 2 – 5, 2011 SESSION CONCURRENT SESSION CONCURRENT
    ISSN 1937-2809 online Journal of Supplement to the November 2011 Vertebrate Paleontology Vertebrate Society of Vertebrate Paleontology Society of Vertebrate 71st Annual Meeting Paleontology Society of Vertebrate Las Vegas Paris Nevada, USA Las Vegas, November 2 – 5, 2011 Program and Abstracts Society of Vertebrate Paleontology 71st Annual Meeting Program and Abstracts COMMITTEE MEETING ROOM POSTER SESSION/ CONCURRENT CONCURRENT SESSION EXHIBITS SESSION COMMITTEE MEETING ROOMS AUCTION EVENT REGISTRATION, CONCURRENT MERCHANDISE SESSION LOUNGE, EDUCATION & OUTREACH SPEAKER READY COMMITTEE MEETING POSTER SESSION ROOM ROOM SOCIETY OF VERTEBRATE PALEONTOLOGY ABSTRACTS OF PAPERS SEVENTY-FIRST ANNUAL MEETING PARIS LAS VEGAS HOTEL LAS VEGAS, NV, USA NOVEMBER 2–5, 2011 HOST COMMITTEE Stephen Rowland, Co-Chair; Aubrey Bonde, Co-Chair; Joshua Bonde; David Elliott; Lee Hall; Jerry Harris; Andrew Milner; Eric Roberts EXECUTIVE COMMITTEE Philip Currie, President; Blaire Van Valkenburgh, Past President; Catherine Forster, Vice President; Christopher Bell, Secretary; Ted Vlamis, Treasurer; Julia Clarke, Member at Large; Kristina Curry Rogers, Member at Large; Lars Werdelin, Member at Large SYMPOSIUM CONVENORS Roger B.J. Benson, Richard J. Butler, Nadia B. Fröbisch, Hans C.E. Larsson, Mark A. Loewen, Philip D. Mannion, Jim I. Mead, Eric M. Roberts, Scott D. Sampson, Eric D. Scott, Kathleen Springer PROGRAM COMMITTEE Jonathan Bloch, Co-Chair; Anjali Goswami, Co-Chair; Jason Anderson; Paul Barrett; Brian Beatty; Kerin Claeson; Kristina Curry Rogers; Ted Daeschler; David Evans; David Fox; Nadia B. Fröbisch; Christian Kammerer; Johannes Müller; Emily Rayfield; William Sanders; Bruce Shockey; Mary Silcox; Michelle Stocker; Rebecca Terry November 2011—PROGRAM AND ABSTRACTS 1 Members and Friends of the Society of Vertebrate Paleontology, The Host Committee cordially welcomes you to the 71st Annual Meeting of the Society of Vertebrate Paleontology in Las Vegas.
    [Show full text]
  • Phytoliths of the Barstow Formation Through the Middle Miocene Climatic Optimum: Preliminary Findings Katharine M
    Phytoliths of the Barstow Formation through the Middle Miocene Climatic Optimum: preliminary findings Katharine M. Loughney 1,2 and Selena Y. Smith 1, 1 Museum of Paleontology, University of Michigan, 1109 Geddes Ave., Ann Arbor, MI 48109 2 Department of Earth & Environmental Sciences, University of Michigan, 1100 North University Ave., Ann Arbor, MI 48109 abstract—The Middle Miocene Climatic Optimum (MMCO) was an interval of signif- icant warming between 17.0 – 14.0 Ma, and a record of the interval is preserved in its entirety in the type Barstow Formation (19.3 – 13.3 Ma) of southern California. In order to understand the biotic impacts of the MMCO, it is necessary to understand vegetation; however, macrofloral records from the middle Miocene in this region are rare and do not span the MMCO. Phytoliths (plant silica) can be preserved in continental sediments even when macrofossil or pollen remains are not, and they can be diagnostic of specific plant clades and/or functional groups, some of which are useful environmental indica- tors. Sixty-eight sediment samples were collected from 12 stratigraphic sections measured within the Barstow Formation in the Mud Hills, Calico Mountains, and Daggett Ridge, and 39 samples were processed for phytoliths. Ten samples yielded phytoliths, although phytoliths were rare in most of these samples. Paleosols from the uppermost part of the Barstow Formation yielded the most abundant and most diverse phytolith assemblages, including grass bilobates and echinate spheres of palms; grass phytoliths were also identi- fied in samples from the Owl Conglomerate and Middle members but were rare. These phytolith data provide evidence that grasses were present throughout deposition of the Barstow Formation, and that they coexisted with palms in mixed-vegetation habitats.
    [Show full text]
  • Episodes 149 September 2009 Published by the International Union of Geological Sciences Vol.32, No.3
    Contents Episodes 149 September 2009 Published by the International Union of Geological Sciences Vol.32, No.3 Editorial 150 IUGS: 2008-2009 Status Report by Alberto Riccardi Articles 152 The Global Stratotype Section and Point (GSSP) of the Serravallian Stage (Middle Miocene) by F.J. Hilgen, H.A. Abels, S. Iaccarino, W. Krijgsman, I. Raffi, R. Sprovieri, E. Turco and W.J. Zachariasse 167 Using carbon, hydrogen and helium isotopes to unravel the origin of hydrocarbons in the Wujiaweizi area of the Songliao Basin, China by Zhijun Jin, Liuping Zhang, Yang Wang, Yongqiang Cui and Katherine Milla 177 Geoconservation of Springs in Poland by Maria Bascik, Wojciech Chelmicki and Jan Urban 186 Worldwide outlook of geology journals: Challenges in South America by Susana E. Damborenea 194 The 20th International Geological Congress, Mexico (1956) by Luis Felipe Mazadiego Martínez and Octavio Puche Riart English translation by John Stevenson Conference Reports 208 The Third and Final Workshop of IGCP-524: Continent-Island Arc Collisions: How Anomalous is the Macquarie Arc? 210 Pre-congress Meeting of the Fifth Conference of the African Association of Women in Geosciences entitled “Women and Geosciences for Peace”. 212 World Summit on Ancient Microfossils. 214 News from the Geological Society of Africa. Book Reviews 216 The Geology of India. 217 Reservoir Geomechanics. 218 Calendar Cover The Ras il Pellegrin section on Malta. The Global Stratotype Section and Point (GSSP) of the Serravallian Stage (Miocene) is now formally defined at the boundary between the more indurated yellowish limestones of the Globigerina Limestone Formation at the base of the section and the softer greyish marls and clays of the Blue Clay Formation.
    [Show full text]
  • 3.5 Geology/Soils
    3.5 GEOLOGY/SOILS 3.5.1 INTRODUCTION This section describes the project’s impacts related to geology and soils, including such factors as seismology, soils, topography, and erosion. It also includes an examination of potential hazards associated with potential damage to proposed structures and infrastructure from ground shaking, potential liquefaction hazards and soils and soils stability. Applicable laws, regulations and relevant local planning policies that pertain to geology are also discussed. Much of the information contained in this subsection was based upon the following geotechnical reports submitted by consultants under contract to the Chandler’s Palos Verdes Sand and Gravel Company and the peer review of those technical studies by Arroyo/Willdan Geotechnical: Geologic Constraints Investigation of the Chandler’s Inert Solid Land Fill Quarry and Surrounding Properties, Rolling Hills Estates, California, Earth Consultants International, June 15, 2000. Phase I Geologic and Geotechnical Engineering Study to Determine Potential Development Areas within the Chandler’s P.V. Sand and Gravel Company Property, Adjacent Trust Properties and the Rolling Hills Country Club, Rolling Hills Estates, California, Neblett & Associates, Inc., December 2001. Fault Investigation, Phases I and II, Chandler Quarry and Rolling Hills Country Club, Palos Verdes Estates, California, Neblett & Associates, Inc., April 29, 2005. Geotechnical Review, Geologic and Geotechnical Engineering Study, Potential Development Areas within the Chandler’s P.V. Sand and Gravel Company Property, Adjacent Trust Properties, and the Rolling Hills Country Club, City of Rolling Hills Estates, California, prepared by Arroyo Geotechnical, September 24, 2007. Review of Response Report, Geotechnical Review, Geologic and Geotechnical Engineering Study, Potential Development Areas within the Chandler’s P.V.
    [Show full text]
  • 1 the Volume of the Complete Palos Verdes Anticlinorium: Stratigraphic
    The Volume of the Complete Palos Verdes Anticlinorium: Stratigraphic Horizons for the Community Fault Model Christopher Sorlien, Leonardo Seeber, Kris Broderick, Doug Wilson Figure 1: Faults, earthquakes, and locations. Lower hemisphere earthquake focal mechanisms, labeled by year, are from USGS and SCEC (1994), with location of 1930 earthquake (open circle) from Hauksson and Saldivar (1986). The surface or seafloor traces, or upper edges of blind faults are from the Southern California Earthquake Center Community Fault Model (Plesch and Shaw, 2002); other faults are from Sorlien et al. (2006). Figure 2 is located by red dashed polygon. L.A.=Los Angeles (downtown); LB=Long Beach (city and harbor); PVA=Palos Verdes anticlinorium, Peninsula and Hills, PVF=Palos Verdes fault; SPBF=San Pedro Basin fault; SMM=Santa Monica Mountains; SPS=San Pedro Shelf. Structural Setting If the water and post-Miocene sedimentary rocks were removed, the Los Angeles (L.A.) area would have huge relief, most of which was generated in the Plio-Pleistocene (Fig. 1; Wright, 1991). The five km-deep L.A. basin would be isolated from other basins to the SW by a major anticline-ridge, the Palos Verdes Anticlinorium (PVA), parallel to the current NW-SE coastline (Davis et al., 1989; Figures 2, 3). The Palos Verdes Hills have been long recognized as a contractional structure, but of dimensions similar to the peninsula (e.g., Woodring et al., 1946). This prominent topographic feature is instead only the exposed portion of the much larger PVA (Fig 2). Submerged parts of the PVA had previously been interpreted as separate anticlines (Nardin and Henyey, 1978; Legg et al., 2004) related in part to bends in strike-slip faults (Ward and Valensise, 1994), rather than a single complex structure above low-angle (oblique) thrust faults.
    [Show full text]