DOCSLIB.ORG

Using Geophysical Well Log Analysis and Geostatistics to Map

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Using Geophysical Well Log Analysis and Geostatistics to Map USING GEOPHYSICAL WELL LOG ANALYSIS AND GEOSTATISTICS TO MAP GROUNDWATER TDS DISTRIBUTIONS IN THE FRUITVALE AND ROSEDALE RANCH OIL FIELDS, KERN COUNTY, CALIFORNIA A Thesis Presented to the faculty of the Department of Geology California State University, Sacramento Submitted in partial satisfaction of the requirements for the degree of MASTER OF SCIENCE in Geology by Michael J. Stephens SUMMER 2017 USING GEOPHYSICAL WELL LOG ANALYSIS AND GEOSTATISTICS TO MAP GROUNDWATER TDS DISTRIBUTIONS IN THE FRUITVALE AND ROSEDALE RANCH OIL FIELDS, KERN COUNTY, CALIFORNIA A Thesis by Michael J. Stephens Approved by: __________________________________, Committee Chair Dr. David Shimabukuro __________________________________, Second Reader Dr. Steven Skinner __________________________________, Third Reader Dr. Jan Gillespie ____________________________ Date ii Student: Michael J. Stephens I certify that this student has met the requirements for format contained in the University format manual, and that this thesis is suitable for shelving in the Library and credit is to be awarded for the thesis. __________________________, Graduate Coordinator ___________________ Dr. Kevin Cornwell Date Department of Geology iii Abstract of USING GEOPHYSICAL WELL LOG ANALYSIS AND GEOSTATISTICS TO MAP GROUNDWATER TDS DISTRIBUTIONS IN THE FRUITVALE AND ROSEDALE RANCH OIL FIELDS, KERN COUNTY, CALIFORNIA by Michael J. Stephens With the recent drought in California, a greater demand has been placed on groundwater resources. Publicly-available data indicate that produced water from oil and gas extraction in California is commonly being injected into the subsurface for disposal at relatively shallow depths in some oil fields. This may conflict with the U.S. Environmental Protection Agency (EPA) Safe Drinking Water Act and California Senate Bill 4. These measures protect groundwater containing < 10,000 ppm total dissolved solids (TDS), also defined as underground sources of drinking water (USDW). Groundwater TDS maps are needed to identify and protect the USDW because there is no current survey of the USDW boundary. Direct measurements of groundwater TDS are not common, which necessitates using alternative methods to quantify TDS. This study uses the resistivity-porosity (RP) method to calculate TDS from resistivity, porosity, and iv temperature measurements recorded in borehole geophysical data. We use existing measured geochemical data to guide proper parameterization of the petrophysical equations by examining comparisons with the ground truth data. The RP method is only accurate within clean, wet sand intervals. Hydrocarbons and shale, if present, distort the TDS calculations, rendering inaccurate results. Due to the large number of wells needing to be analyzed, an algorithm was coded in Python to process digitized geophysical well data to identify clean sand intervals where TDS calculations are more accurate. The RP-derived TDS data were fed into a 3D geostatistical kriging model to create an interpolated volume model of TDS. The model is validated by comparing the predicted TDS values to the measured TDS data. The average error is 11%, with a correlation of R2 = 0.97. The model was used to visualize a cross section throughout the Fruitvale and Rosedale Ranch oil fields in the San Joaquin Basin of California. Groundwater TDS in the area varies significantly. The 10,000 ppm TDS boundary is at ~3,500 ft in Rosedale Ranch and deepens to the southeast in Fruitvale to ~4,500 ft. According to the data, several factors including depth, stratigraphy, faults, and fresh water recharge control the TDS distribution. Within the Rosedale Ranch area, Miocene normal faults and a low-permeable clay layer isolates aquifers from fresh water recharge from the Kern River. Stratigraphic control seems to dominate the TDS structure in the area between the fields. The groundwater in the Fruitvale area is flushed by recharge from the Kern River. v This study provides a realistic and effective approach to quantify formation water TDS with available data as well as a better understanding of the controls on groundwater TDS, which can assist future mapping efforts and lead to better information for water resources managers. __________________________________, Committee Chair Dr. David Shimabukuro ____________________________ Date vi ACKNOWLEDGEMENTS As these things are never the result of a single person’s work, I’d like to recognize those that have supported me throughout the development of this thesis. First and foremost, my deepest appreciation to Dr. Dave Shimabukuro for providing guidance throughout my graduate career. The time and energy he spent working on this project with me is immeasurable. To Dr. Steve Skinner who taught me programming. His course and guidance enabled me to take on this project. Thank you to Dr. Jan Gillespie for her advice and guidance throughout this project - her knowledge of California geology was essential in making my thesis a success. Finally, many thanks to Will Chang for serving as an informal advisor for much of this project and for sharing his knowledge of geostatistics which aided in the completion of my thesis. Thank you to the California State Water Resources Control Board and the U.S. Geological Survey for providing funding for this project. They have been valuable sources of scientific knowledge and collaboration, and I am grateful for the opportunity to work with these organizations. As this research was aided by copious data, I am grateful to the Water Resources Group at CSUS that spent countless hours collecting and quality checking data used in this study. Thank you to my parents, Bob and Linda, who have always supported me and encouraged me to continue my education. They have personally demonstrated the value of education. Lastly, thank you to my wife, Sarah, who inspires me to follow my passions regardless of the challenges that may arise. vii TABLE OF CONTENTS Page Acknowledgements .................................................................................................... vii List of Figures ............................................................................................................. xi INTRODUCTION .........................................................................................................1 BACKGROUND ......................................................................................................... 7 Regional Geology ............................................................................................. 7 Local Geology ................................................................................................... 9 Production History .......................................................................................... 14 Hydrology ....................................................................................................... 17 METHODS…. .............................................................................................................18 Available TDS Data ........................................................................................ 18 Petrophysical Equations .................................................................................. 21 Porosity Model ................................................................................................ 25 Temperature Model ......................................................................................... 28 TDS Calculations ............................................................................................ 30 Geostatistics .................................................................................................... 35 Exploratory Data Analysis and Transformation ................................. 37 The Variogram .................................................................................... 39 Kriging System ................................................................................... 41 Stratigraphic Data ........................................................................................... 43 Fault Data ........................................................................................................ 43 viii RESULTS & DISCUSSION....................................................................................... 45 Groundwater TDS Distribution....................................................................... 45 Model Validation ............................................................................................ 52 Geostatistical Model Validation ......................................................... 52 RP-Calculations Validation ................................................................ 55 Potential Controls on TDS Structure .............................................................. 63 CONCLUSIONS......................................................................................................... 71 Appendix A. Resistivity-porosity derived TDS values ............................................ 72 Appendix B. Example code for TDS calculations .................................................... 82 References .................................................................................................................. 87 ix LIST OF FIGURES Figures Page 1. Wastewater injection depth in California ......................................................... 2 2. Map of the San Joaquin Valley ......................................................................... 4 3. Map of the study area .......................................................................................
Load more

Recommended publications
  • Download Full Article in PDF Format
    A new marine vertebrate assemblage from the Late Neogene Purisima Formation in Central California, part II: Pinnipeds and Cetaceans Robert W. BOESSENECKER Department of Geology, University of Otago, 360 Leith Walk, P.O. Box 56, Dunedin, 9054 (New Zealand) and Department of Earth Sciences, Montana State University 200 Traphagen Hall, Bozeman, MT, 59715 (USA) and University of California Museum of Paleontology 1101 Valley Life Sciences Building, Berkeley, CA, 94720 (USA) [email protected] Boessenecker R. W. 2013. — A new marine vertebrate assemblage from the Late Neogene Purisima Formation in Central California, part II: Pinnipeds and Cetaceans. Geodiversitas 35 (4): 815-940. http://dx.doi.org/g2013n4a5 ABSTRACT e newly discovered Upper Miocene to Upper Pliocene San Gregorio assem- blage of the Purisima Formation in Central California has yielded a diverse collection of 34 marine vertebrate taxa, including eight sharks, two bony fish, three marine birds (described in a previous study), and 21 marine mammals. Pinnipeds include the walrus Dusignathus sp., cf. D. seftoni, the fur seal Cal- lorhinus sp., cf. C. gilmorei, and indeterminate otariid bones. Baleen whales include dwarf mysticetes (Herpetocetus bramblei Whitmore & Barnes, 2008, Herpetocetus sp.), two right whales (cf. Eubalaena sp. 1, cf. Eubalaena sp. 2), at least three balaenopterids (“Balaenoptera” cortesi “var.” portisi Sacco, 1890, cf. Balaenoptera, Balaenopteridae gen. et sp. indet.) and a new species of rorqual (Balaenoptera bertae n. sp.) that exhibits a number of derived features that place it within the genus Balaenoptera. is new species of Balaenoptera is relatively small (estimated 61 cm bizygomatic width) and exhibits a comparatively nar- row vertex, an obliquely (but precipitously) sloping frontal adjacent to vertex, anteriorly directed and short zygomatic processes, and squamosal creases.
    [Show full text]
  • Reef-Coral Fauna of Carrizo Creek, Imperial County, California, and Its Significance
    THE REEF-CORAL FAUNA OF CARRIZO CREEK, IMPERIAL COUNTY, CALIFORNIA, AND ITS SIGNIFICANCE . .By THOMAS WAYLAND VAUGHAN . INTRODUCTION. occur has been determined by Drs . Arnold and Dall to be lower Miocene . The following conclusions seem warranted : Knowledge of the existence of the unusually (1) There was water connection between the Atlantic and interesting coral fauna here discussed dates Pacific across Central America not much previous to the from the exploration of Coyote Mountain (also upper Oligocene or lower Miocene-that is, during the known as Carrizo Mountain) by H . W. Fair- upper Eocene or lower Oligocene . This conclusion is the same as that reached by Messrs. Hill and Dall, theirs, how- banks in the early nineties.' Dr. Fairbanks ever, being based upon a study of the fossil mollusks . (2) sent the specimens of corals he collected to During lower Miocene time the West Indian type of coral Prof. John C. Merriam, at the University of fauna extended westward into the Pacific, and it was sub- California, who in turn sent them to me . sequent to that time that the Pacific and Atlantic faunas There were in the collection representatives of have become so markedly differentiated . two species and one variety, which I described As it will be made evident on subsequent under the names Favia merriami, 2 Stephano- pages that this fauna is much younger than ctenia fairbanksi,3 and Stephanoccenia fair- lower Miocene, the inference as to the date of banksi var. columnaris .4 As the geologic hori- the interoceanic connection given in the fore- zon was not even approximately known at that going quotation must be modified .
    [Show full text]
  • Deep Sea Drilling Project Initial Reports Volume 13
    M. HAJOS 34.5. THE MEDITERRANEAN DIATOMS Marta Hajos, Hungarian Geological Institute, Budapest, Hungary INTRODUCTION species. The relevant information has been obtained from the references cited at the end of this chapter and from Ten washed samples taken at eight levels from the drill investigations of Hungarian fossiliferous localities. cores of the Mediterranean expedition of the Deep Sea The 175 taxa investigated belong primarily to the phyla Drilling Project were sent for study to the present writer by Chrysophyta and Bacillariophyta, and are accompanied in Paulian Dumitrica of the Geological Institute, Bucharest, subordinate numbers by representatives of Phytolitharia, Rumania. He had found these samples to be the richest Acritarcha, Radiolaria and Porifera. diatom-bearing sediments both in terms of species and The paleoecological assignments shown in Table 1 and individuals. the complete floral spectrum allow three paleo-ecological Two samples from Core 13 of Site 124—Balearic Rise1 divisions, representing three areas of the Mediterranean and were selected near levels of finely laminated dolomitic three different sedimentary facies, to be distinguished. marls with dark green to black interbeds. This dolomitic unit is part of the evaporite series cored in the deep Balearic Division 1 — Siliceous Dolomitic Marls of Site 124 Basin. All six samples from Sites 127 and 128 in the 2 Hellenic Trench of the Ionian Basin are from layers of The sediments of the two samples from Site 124 dark sapropelitic ooze, where the siliceous microfauna is (124-13-2, 89-90 cm and 124-13-2, 127-129 cm) were particularly abundant. The remaining two samples are from apparently deposited under the same ecological conditions.
    [Show full text]
  • Gastropoda:Muricidae
    The malacologicalsocietymalacological society of Japan Jeur. Malac,) fi re VENUS {Jap. - Vol, 5z No. 3 ( l99g): 2e9 223 Originand Biogeographic History of Ceratostoma (Gastropoda: Muricidae) Kazutaka AMANo and Geerat J. VERMEIJ of943ofGeoscience. Jbetsu Uhiversity oj' EZIucation. i2xmayashiki-1. Jbetsu, MigataDqpartmentPrellercture, -85i2 Japan, and Department of Geolegy and Center for Population Uitiversity Calijbrnia at Davis, One Shields Avenue, Davis, CA 95616 USABiology Abstract: We examined the two Neogene species of the ocenebrine muricid gastropod genus Ceratostoma Herrmannsen, 1846, from Japan and North Korea, namely, C. makiyamai The (Hatai & Kotaka, 1952) and C. sp,, both from the early middle Miecene. genus Ceratostotna is divisible into fouT groups based on C. nuttalli (Conrad), C. virginiae (Maury), C, fotiatum (Gemelin), and C. rorijIuum (Adams & Reeve). Three Miocene species from Kamehatka assigned by Russian workers to Ceratostoma are difficult to evaluate owing to poor preservation. Purpura turris Nomland, from the Pliecene of California, which was assigned to Ceratostoma by earlicr authors, is here tentatively assigned to Crassilabrum Jousseaume, 1880, have arisen the the early Miocene, it The genus Ceratostoma may in Atlantic. By had reached California, and then spTead westward to northeast Asia by earLy middle Mio- Miocene ccne time. This pattern of east to west expansion during the early half of the also characterizes many other north-temperate marine genera, including the ocenebrine NiiceUa. Keywords: origin, biogeography, Ceratostoma, Muricidae Introduction muricid Ceratostoma liye in shallow Recent species of the ocenebrine gastropod genus waters on both sides of the temperate and boreal North Pacific. There are six living species: C nuttaUi (Conrad) from California and Baja California, C.
    [Show full text]
  • Qt53v080hx.Pdf
    UC Berkeley PaleoBios Title A new Early Pliocene record of the toothless walrus Valenictus (Carnivora, Odobenidae) from the Purisima Formation of Northern California Permalink https://escholarship.org/uc/item/53v080hx Journal PaleoBios, 34(0) ISSN 0031-0298 Author Boessenecker, Robert W. Publication Date 2017-06-15 DOI 10.5070/P9341035289 Peer reviewed eScholarship.org Powered by the California Digital Library University of California PaleoBios 34:1-6, June 15, 2017 PaleoBios OFFICIAL PUBLICATION OF THE UNIVERSITY OF CALIFORNIA MUSEUM OF PALEONTOLOGY Boessenecker, Robert W. (2017). A New Early Pliocene Record of the Toothless Walrus Valenictus (Carnivora, Odobenidae) from the Purisima Formation of Northern California. Cover photo: Life restoration of the extinct Pliocene walrus Valenictus and flightless auks (Mancalla) hauled out on the rocky shore of the uplifted Coast Ranges of California (top right); cliff exposures of the Purisima Formation near Santa Cruz, from where Valenictus was collected by Wayne Thompson (left); bivalves, chiefly Clinocardium meekianum, exposed in the Purisima Formation near the locality (bottom). Photo credit and original artwork: Robert W. Boessenecker. Citation: Boessenecker, Robert W. 2017. A New Early Pliocene Record of the Toothless Walrus Valenictus (Carnivora, Odobenidae) from the Puri- sima Formation of Northern California. PaleoBios, 34. ucmp_paleobios_35289 A New Early Pliocene Record of the Toothless Walrus Valenictus (Carnivora, Odobenidae) from the Purisima Formation of Northern California ROBERT W. BOESSENECKER1,2 1Department of Geology and Environmental Geosciences, College of Charleston, Charleston, SC 29424; [email protected] 2University of California Museum of Paleontology, University of California, Berkeley, CA 94720 The walrus (Odobenus rosmarus) is a large tusked molluskivore that inhabits the Arctic and is the sole living member of the family Odobenidae.
    [Show full text]
  • Appendix G Paleontological Resources Assessment
    Appendix G Paleontological Resources Assessment Paleontological Resource Assessment for the California Flats Solar Project, Monterey and San Luis Obispo Counties, California Jessica L. DeBusk Prepared By Applied EarthWorks, Inc. 743 Pacific Street, Suite A San Luis Obispo, CA 93401 Prepared For Element Power US, LLC 421 SW Sixth Avenue, Suite 1000 Portland, OR 97204 April 2013 draft SUMMARY OF FINDINGS At the request of Element Power US, LLC, parent company of California Flats Solar, LLC (the Applicant), Applied EarthWorks Inc. (Æ) performed a paleontological resource assessment for the California Flats Solar Project (Project) located southeast of Parkfield in Monterey and San Luis Obispo counties, California. The study consisted of a museum records search, a comprehensive literature and geologic map review, and a field survey. This report summarizes the methods and results of the paleontological resource assessment and provides Project-specific management recommendations. This assessment included a comprehensive review of published and unpublished literature and museum collections records maintained by the Natural History Museum of Los Angeles County (LACM) and the University of California Museum of Paleontology (UCMP). The purpose of the literature review and museum records search was to identify the geologic units underlying the Project area and to determine whether or not previously recorded paleontological localities occur either within the Project boundaries or within the same geologic units elsewhere. The museum records search was followed by a field survey. The purpose of the field survey was to visually inspect the ground surface for exposed fossils and to evaluate geologic exposures for their potential to contain preserved fossil material at the subsurface.
    [Show full text]
  • Geology and Paleontology of the Late Miocene Wilson Grove Formation at Bloomfield Quarry, Sonoma County, California
    Geology and Paleontology of the Late Miocene Wilson Grove Formation at Bloomfield Quarry, Sonoma County, California 2 cm 2 cm Scientific Investigations Report 2019–5021 U.S. Department of the Interior U.S. Geological Survey COVER. Photographs of fragments of a walrus (Gomphotaria pugnax Barnes and Raschke, 1991) mandible from the basal Wilson Grove Formation exposed in Bloomfield Quarry, just north of the town of Bloomfield in Sonoma County, California (see plate 8 for more details). The walrus fauna at Bloomfield Quarry is the most diverse assemblage of walrus yet reported worldwide from a single locality. cm, centimeter. (Photographs by Robert Boessenecker, College of Charleston.) Geology and Paleontology of the Late Miocene Wilson Grove Formation at Bloomfield Quarry, Sonoma County, California By Charles L. Powell II, Robert W. Boessenecker, N. Adam Smith, Robert J. Fleck, Sandra J. Carlson, James R. Allen, Douglas J. Long, Andrei M. Sarna-Wojcicki, and Raj B. Guruswami-Naidu Scientific Investigations Report 2019–5021 U.S. Department of the Interior U.S. Geological Survey U.S. Department of the Interior DAVID BERNHARDT, Secretary U.S. Geological Survey James F. Reilly II, Director U.S. Geological Survey, Reston, Virginia: 2019 For more information on the USGS—the Federal source for science about the Earth, its natural and living resources, natural hazards, and the environment—visit https://www.usgs.gov/ or call 1–888–ASK–USGS (1–888–275–8747). For an overview of USGS information products, including maps, imagery, and publications, visit https://store.usgs.gov/. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S.
    [Show full text]
  • On the Reconciliation of Biostratigraphy and Strontium Isotope Stratigraphy of Three Southern Californian Plio-Pleistocene Formations
    On the reconciliation of biostratigraphy and strontium isotope stratigraphy of three southern Californian Plio-Pleistocene formations Alexandra J. Buczek1, Austin J.W. Hendy2, Melanie J. Hopkins1, and Jocelyn A. Sessa3,† 1 Division of Paleontology, American Museum of Natural History, Central Park West & 79th Street New York, New York 10024, USA 2 Department of Invertebrate Paleontology, Natural History Museum of Los Angeles County, 900 Exposition Blvd., Los Angeles, California 90007, USA 3 Department of Biodiversity, Earth and Environmental Science, Academy of Natural Sciences of Drexel University, 1900 Benjamin Franklin Parkway, Philadelphia, Pennsylvania 19103, USA ABSTRACT INTRODUCTION 2006; Powell et al., 2009; Squires, 2012; Ven- drasco et al., 2012). Based primarily on regional The San Diego Formation, Pico Forma- The mid-Pliocene warm period (ca 3 Ma; macrofossil and microfossil biostratigraphy, tion, Careaga Sandstone, and Foxen Mud- Jansen et al., 2007) was a time of high global these units are hypothesized to be late Pliocene stone of southern California are thought to temperatures (2 °C to 3 °C above pre-industrial to early Pleistocene in age (Figs. 1 and 3), but no be late Pliocene to early Pleistocene; however, temperatures) and high atmospheric CO2 con- numerical ages exist to confirm this hypothesis. numerical ages have not been determined. centrations (360–400 ppm) (Jansen et al., 2007). Previous age determinations must be revisited Following assessment of diagenetic altera- These climatic conditions, combined with the
    [Show full text]
  • New 87 Sr/88 Sr Data from Invertebrate Macrofossils in the Neogene Etchegoin Formation, San Joaquin Basin, California K.B
    New 87 Sr/88 Sr data from invertebrate macrofossils in the Neogene etchegoin formation, San Joaquin basin, California K.B. Loomis Isochron/West, Bulletin of Isotopic Geochronology, v. 58, pp. 17-21 Downloaded from: https://geoinfo.nmt.edu/publications/periodicals/isochronwest/home.cfml?Issue=58 Isochron/West was published at irregular intervals from 1971 to 1996. The journal was patterned after the journal Radiocarbon and covered isotopic age-dating (except carbon-14) on rocks and minerals from the Western Hemisphere. Initially, the geographic scope of papers was restricted to the western half of the United States, but was later expanded. The journal was sponsored and staffed by the New Mexico Bureau of Mines (now Geology) & Mineral Resources and the Nevada Bureau of Mines & Geology. All back-issue papers are available for free: https://geoinfo.nmt.edu/publications/periodicals/isochronwest This page is intentionally left blank to maintain order of facing pages. 17 NEW "Sr/««Sr DATA FROM tNVERTEBRATE MACROFOSSILS IN THE NEOGENE ETCHEGOIN FORMATION, SAN JOAQUIN BASIN, CALIFORNIA KAREN B. LOOMIS ARCO Exploration and Production Technology, Piano, TX 75075 The Etchegoin Group, comprised of the Jacalitos, previously unpublished ®^Sr/®®Sr data from marine inverte Etchegoin, and San Joaquin formations, forms the upper brate macrofossils suggesting that the Etchegoin part of the sedimentary fill of the San Joaquin forearc basin Formation in the west-central San Joaquin basin ranges of central California. This stratigraphic sequence is locally from late Miocene to early Pliocene in age. fossiliferous (i.e., containing plant fossils, invertebrate and vertebrate macrofossils) and consists of siltstone, sand METHODS stone, conglomerate, and rare tuff beds deposited in shallow-marine, marginal-marine, and nonmarine environ The Etchegoin Group was studied in the Jacalitos, ments during the late Neogene regression of the San Kreyenhagen, and Kettleman hills in the western San Joaquin Sea (Loomis, 1990a, 1990b).
    [Show full text]
  • Lithologic Characteristics of Pliocene Rocks Cored at Elk Hills, Kern County, California
    Lithologic Characteristics of Pliocene Rocks Cored at Elk Hills, Kern County, California GEOLOGICAL SURVEY BULLETIN 1332-D Lithologic Characteristics of Pliocene Rocks Cored at Elk Hills, Kern County, California By WILLIAM M. BERRYMAN CONTRIBUTIONS TO ECONOMIC GEOLOGY GEOLOGICAL SURVEY BULLETIN 1332-D A complete sequence of Pliocene rocks cored in Naval Petroleum Reserve No. 1 well324-19R is established as a reference section for subsurface Pliocene rocks in the Elk Hills oil field UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1973 UNITED STATES DEPARTMENT OF THE INTERIOR ROGERS C. B. MORTON, Secretary GEOLOGICAL SURVEY V. E. McKelvey, Director Library of Congress catalog-card No. 73-600064 For sale by the Superintendent of Documents, U. S. Government Printing Office Washington, D. C. 20402 Stock Number 2401-00317 CONTENTS Page Abstract...................................................................................................................... Dl Introduction .............................................................................................................. 1 Purpose of report ............................................................................................ 2 Drilling summary ............................................................................................ 4 Methods of investigation ................................................................................ 4 Acknowledgments ............................................................................................ 5 Stratigraphy
    [Show full text]
  • New K-Ar Ages from Tuffs in the Etchegoin Formation, San Joaquin Basin, Nevada K.B
    New K-Ar ages from tuffs in the etchegoin formation, San Joaquin basin, Nevada K.B. Loomis Isochron/West, Bulletin of Isotopic Geochronology, v. 58, pp. 3-7 Downloaded from: https://geoinfo.nmt.edu/publications/periodicals/isochronwest/home.cfml?Issue=58 Isochron/West was published at irregular intervals from 1971 to 1996. The journal was patterned after the journal Radiocarbon and covered isotopic age-dating (except carbon-14) on rocks and minerals from the Western Hemisphere. Initially, the geographic scope of papers was restricted to the western half of the United States, but was later expanded. The journal was sponsored and staffed by the New Mexico Bureau of Mines (now Geology) & Mineral Resources and the Nevada Bureau of Mines & Geology. All back-issue papers are available for free: https://geoinfo.nmt.edu/publications/periodicals/isochronwest This page is intentionally left blank to maintain order of facing pages. NEW K-Ar AGES FROM TUFFS IN THE ETCHEGOIN FORMATION, SAN JOAQUIN BASIN, CALIFORNIA KAREN B. LOOMIS ARCO Exploration and Production Technology, Piano, TX 75075 Volcanic tuff beds are interbedded with sedimentary rocks of the upper Miocene and Pliocene Etchegoin Formation in the west- central San Joaquin basin of California (figs. N/v/l 1, 2). Three regionally extensive tuff units, San Joaquin Fm. informally termed the "Gate","Deadman", and "Den Hartog" tuffs, were mapped 6000 (Loomis, 1990b, Plate 1) in the Jacalitos Den Hartog tuff Creek-Zapato Chino Creek area, near the 5.0 ± 0.3 Ma (K-Ar) towns of Coalinga and Avenal (fig. 2). Potassium-argon dates were obtained from (3-26-89-6) these three tuff beds and the results are 5 ft (1.5 m) thick presented in this report.
    [Show full text]
  • Jahns 1954P59.Pdf
    OLOGY [Bull. 170 1can 7. MARINE-NONMARINE RELATIONSHIPS IN THE CENOZOIC SECTION OF CALIFORNIA* .c, Childs, 1921, op. cit. BY J. WYATT DURHAM,t RICHARD H . JAHNS, t ltz, J. R., 1037, A late Cenozoic vertebrate fauna from the Coso Mountains, AND DONALD E . SAVAGE§ yo County, California : Carnegie Inst. Washington Pub. No. 487, pp. 75-109. INTRODUCTION Latest Highly fossiliferous marine sediments of Cenozoic age are widely 1gtonian 111•', 1' k, Childs, 1921, op. cit. distributed in the coastal parts of central and southern California, C'_q·,~/, FR E </;,:'!lo as well as in the Sacramento-San Joaquin Valley region farther in­ · ~ cholabrean 0-?~ 1ey, R. ,V., and Mason, H . L., 1933, A Pleistocene flora from the asphalt land. Even more widespread are nonmarine, chiefly terrestrial, ) •'8 1'/ ' posits at Carpinteria, California: Carnegie Inst. 'Vnshington Pub. No. 415, sequences of Cenozoic strata, many of which contain vertebrate .\)~ I N Y 0 . 4u-79. faunas characterized by a dominance of mammalian forms. These <I '""'...', k, Chester, 1953, Rancho La Bren: Los Angeles County l\Iuseum, Science strata are most abundant in the Mojave Desert region and in the r., no. 5, Paleontology no. 9, 5th ed., pp. 1-81. interior parts of areas that lie nearer the coast. Marine and nonmarine strata are in juxtaposition or interfinger with one another at many places, especially in the southern Coast S A N Ranges and the San Joaquin basin to the east, in the Transverse 8ERNAROINO Ranges and adjacent basins, and in several parts of the Peninsular K E R N Range region and the Coachella-Imperial Valley to the east.
    [Show full text]