DOCSLIB.ORG

Manual 2000 Pagemaker

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text

Load more

STUDENT’S MANUAL for 2000 NORTH CAROLINA UNIVERSITIES SUMMER FIELD COURSE in GEOLOGY by P. Geoffrey Feiss Richard Mauger Kevin G. Stewart 1 Acknowledgments This manual has evolved over a decade with the help and assistance of many faculty, TAs, and staff — some forgotten, some not. Among those who deserve thanks are John Bartley, Mary Crump, Cathy Cash, Allen Glazner, Stephen Harper, Richard Spruill, Charles Daniel, Jim Reynolds, Terri Woods, Rick Wooten, and Patsy Webb. © copyright USA 2000 All rights reserved 2 Schedule for 2000 Field Course Date Day Activity 12-May Fri leave North Carolina; Trip West; camp at Cedars of Lebanon State Park, TN 13-May Sat Trip West; camp at Red Rock Canyon State Park, Hinton, OK 14-May Sun Trip West; arrive Abiquiu, NM camp site 15-May Mon Abiquiu, NM; Intoductory Geologic Mapping Project 16-May Tue Abiquiu, NM; Intoductory Geologic Mapping Project 17-May Wed Abiquiu, NM; Intoductory Geologic Mapping Project 18-May Thu Abiquiu, NM; Intoductory Geologic Mapping Project 19-May Fri Taos, NM mapping and landslide project 20-May Sat Taos, NM mapping and landslide project 21-May Sun Taos, NM mapping and landslide project 22-May Mon Taos, NM mapping and landslide project 23-May Tue Taos, NM mapping and landslide project 24-May Wed Taos, NM mapping and landslide project 25-May Thu Taos, NM mapping and landslide project 26-May Fri Field trip, Great Sand Dunes , CO and Raton Basin, NM 27-May Sat Field trip, Great Sand Dunes , CO and Raton Basin, NM 28-May Sun Field trip, Great Sand Dunes , CO and Raton Basin, NM 29-May Mon Cuba, NM, Mapping and hydrology projects 30-May Tue Cuba, NM, Mapping and hydrology projects 31-May Wed Cuba, NM, Mapping and hydrology projects 1-Jun Thu Cuba, NM, Mapping and hydrology projects 2-Jun Fri Cuba, NM, Mapping and hydrology projects 3-Jun Sat Cuba, NM, Mapping and hydrology projects 4-Jun Sun Cuba, NM, Mapping and hydrology projects 5-Jun Mon Cuba, NM, Mapping and hydrology projects 6-Jun Tue Cuba, NM, Mapping and hydrology projects 7-Jun Wed Field Trip, Mesa Verde, CO and Creede, CO 8-Jun Thu Field Trip, Mesa Verde, CO and Creede, CO 9-Jun Fri Field Trip, Mesa Verde, CO and Creede, CO 10-Jun Sat Gunnison Projects, East Elk Creek campground 11-Jun Sun Gunnison Projects, East Elk Creek campground 13-Jun Mon Gunnison Projects, East Elk Creek campground 14-Jun Tue Gunnison Projects, East Elk Creek campground 15-Jun Wed Gunnison Projects, East Elk Creek campground 16-Jun Thu Gunnison Projects, WSC dorms 17-Jun Fri Gunnison Projects, WSC dorms 18-Jun Sat Gunnison Projects, WSC dorms 19-Jun Sun Gunnison Projects, WSC dorms 20-Jun Mon Gunnison Projects, WSC dorms 21-Jun Tue Gunnison Projects, WSC dorms 22-Jun Wed Gunnison Projects, WSC dorms, pack for trip east 23-Jun Thu Trip East, camp at Wilson Lake State Park, Sylvan Grove, KS 24-Jun Fri Trip East, camp at Cedars of Lebanon State Park, TN 25-Jun Sat Trip East; arrive Raleigh/Chapel Hill, NC late afternoon MAILING ADDRESSES Before June 1 UNC System Geology Field Course c/o Circle A Ranch, Box 2142, Cuba, NM 87013 After June 1 UNC System Geology Field Course c/o Aspinall-Wilson Center Western State College, Gunnison, CO 81230 3 CHAPTER 1 - GENERAL INFORMATION ACADEMIC MATTERS Grading Policy - Independent Work If a student is found to have in his/her possession a copy or copies of map(s) or reports(s) from previous years, the student will be immediately dismissed from the field course.1 All material submitted by you for a grade will represent independent work. This is not as simple as it sounds. In all field exercises you will be working with a field partner and, in addition, we wish to encourage the free exchange of ideas in the field and in “bull sessions” - whenever the spirit moves you. Operationally, the concept of independent work boils down to this: •All data on your maps and in field notes was observed by you. •All work submitted for grading was done by you. An example may suffice. Suppose that in a discussion with another group in the field, you and your partner become aware of an important structure that you had missed in your mapping. On that basis alone, it would not be appropriate to enter that structure on your map or submit your map with that structure shown. You would be advised to enter the idea in your field notebook properly acknowledged as to the source of the idea. How- ever, there is no reason why you and your partner could not, on the basis of that discussion, return to the area in question, see the structure, and then enter the appropriate data on your map (in fact, you may return to the area in question and decide that the other group is completely wrong!). What you call your work must be your own work. We encourage the sharing of ideas and observations (not data) with one another. This is integral to the learning experi- ence. Here’s an example: you encounter a couple of students measuring a strike and dip on an outcrop. You, too, plan to measure the strike and dip of this formation. As you approach, you hear one partner say to the other, “Strike N38W, Dip 51 SE”. What do you do? Hint: you do not enter that in your field notes and walk on. You inspect the outcrop yourself and make your own measurements. After all, they might have measured a foliation, not bed- ding, or been wearing a highly magnetic belt buckle and got the dip in the wrong direction. Problems may arise if you are not careful and circumspect with your maps and field notes during the evenings and other times. Should you leave your map in open view and unattended, you are nearly as guilty as someone who copies from that map — in a court of law you would be held accountable for entrapment. Keep your maps and notes secure and out-of-harm’s way. Do not tempt your colleagues. Unfortunately, it is not unusual for us to hear, six months later, that “so-and-so” copied every map — “everybody knew this”. The problem is that “everybody” but the faculty and TAs know. If you know of such cheating, it is your responsibility to stop it — by confronting the student or reporting it. Why should you expect a TA or faculty member to confront an unknown student not known to have committed grievous acts of unreported dishonesty. 1 For UNC-CH students, this is also an Honor Code violation. 4 Due Dates Course grades are determined on the basis of assigned field course projects. Due dates (subject to revision at the instructor’s discretion) for these projects will be made abundantly clear at the beginning of each exercise. The specific requirements for each of these projects will be spelled out at the same time. Generally speaking, an inked and col- ored geologic map, a stratigraphic column, and possibly one or more structure cross-sec- tions will be required. In some instances a narrative or a description of the lithologic units may also be necessary. The grade reported is based on submitted, graded work combined with the faculty’s subjective impressions of your performance in the field. This latter is based on observation and discussions with each of you in the field by the instructors. The faculty are not grading you on what you know or do not know in the field. They are aware of your motivation, your willingness to contribute to the mapping project, your interest and enthusiasm, your developing field skills and many other factors. The instructors are there to supply guid- ance, answer questions, and observe your progress. It is unlikely that circumstances exist in which it would be advantageous to avoid the instructors while in the field (a course some individuals have chosen in the past). If the instructors never see you, they can neither help you nor give you the benefit of the doubt in grading. This Course Manual This manual should be your Bible/Koran/Torah. It contains instructions, a guide to field methods, guidelines for preparing maps and cross-sections, and lots of useful geologi- cal information. We appreciate constructive comments for future editions. Your instructors may give reading assignments and hold you responsible, at any time, for short quizzes on the manual contents. Be forewarned. We assume that you will have read the manual thoroughly prior to leaving on the trip west from North Carolina. Policy on Making Up Missed Field Work If, because of illness or injury, a student misses a portion of the field work, arrange- ments will have to be made with the faculty in charge of that project as to how this work is to be made-up so that you can submit a complete map. If a student misses a large portion of field time, it is left to the judgment of the faculty and the field camp director to suggest that the student withdraw from all or a portion of the course and repeat the work in a subsequent field season. If injury occurs as a result of carelessness or negligence on the part of the student, especially if that injury occurs during the student’s free time, the faculty will be notably less sympathetic about making special arrangements than if the student is injured in the normal course of field work. RULES AND REGULATIONS Over the years, we have developed a set of rules and regulations to govern various aspects of behavior at field camp.
Recommended publications
  • Geologic Map of the Central San Juan Caldera Cluster, Southwestern Colorado by Peter W

    Geologic Map of the Central San Juan Caldera Cluster, Southwestern Colorado by Peter W

    Geologic Map of the Central San Juan Caldera Cluster, Southwestern Colorado By Peter W. Lipman Pamphlet to accompany Geologic Investigations Series I–2799 dacite Ceobolla Creek Tuff Nelson Mountain Tuff, rhyolite Rat Creek Tuff, dacite Cebolla Creek Tuff Rat Creek Tuff, rhyolite Wheeler Geologic Monument (Half Moon Pass quadrangle) provides exceptional exposures of three outflow tuff sheets erupted from the San Luis caldera complex. Lowest sheet is Rat Creek Tuff, which is nonwelded throughout but grades upward from light-tan rhyolite (~74% SiO2) into pale brown dacite (~66% SiO2) that contains sparse dark-brown andesitic scoria. Distinctive hornblende-rich middle Cebolla Creek Tuff contains basal surge beds, overlain by vitrophyre of uniform mafic dacite that becomes less welded upward. Uppermost Nelson Mountain Tuff consists of nonwelded to weakly welded, crystal-poor rhyolite, which grades upward to a densely welded caprock of crystal-rich dacite (~68% SiO2). White arrows show contacts between outflow units. 2006 U.S. Department of the Interior U.S. Geological Survey CONTENTS Geologic setting . 1 Volcanism . 1 Structure . 2 Methods of study . 3 Description of map units . 4 Surficial deposits . 4 Glacial deposits . 4 Postcaldera volcanic rocks . 4 Hinsdale Formation . 4 Los Pinos Formation . 5 Oligocene volcanic rocks . 5 Rocks of the Creede Caldera cycle . 5 Creede Formation . 5 Fisher Dacite . 5 Snowshoe Mountain Tuff . 6 Rocks of the San Luis caldera complex . 7 Rocks of the Nelson Mountain caldera cycle . 7 Rocks of the Cebolla Creek caldera cycle . 9 Rocks of the Rat Creek caldera cycle . 10 Lava flows premonitory(?) to San Luis caldera complex . .11 Rocks of the South River caldera cycle .
  • Structural Interpretation of the Cherokee Arch, South

    Structural Interpretation of the Cherokee Arch, South

    STRUCTURAL INTERPRETATION OF THE CHEROKEE ARCH, SOUTH CENTRAL WYOMING, USING 3-D SEISMIC DATA AND WELL LOGS by Joel Ysaccis B. ABSTRACT The purpose of this study is to use 3-D seismic data and well logs to map the structural evolution of the Cherokee Arch, a major east-west trending basement high along the Colorado-Wyoming state line. The Cherokee Arch lies along the Cheyenne lineament, a major discontinuity or suture zone in the basement. Recurrent, oblique-slip offset is interpreted to have occurred along faults that make up the arch. Gas fields along the Cherokee Arch produce from structural and structural-stratigraphic traps, mainly in Cretaceous rocks. Some of these fields, like the South Baggs – West Side Canal fields, have gas production from multiple pays. The tectonic evolution of the Cherokee Arch has not been previously studied in detail. About 315 mi2 (815 km2) of 3-D seismic data were analyzed in this study to better understand the kinematic evolution of the area. The interpretation involved mapping the Madison, Shinarump, Above Frontier, Mancos, Almond, Lance/Fox Hills and Fort Union horizons, as well as defining fault geometries. Structure maps on these horizons show the general tendency of the structure to dip towards the west. The Cherokee Arch is an asymmetrical anticline in the hanging wall, which is mainly transected by a south-dipping series of east-west striking thrust faults. The interpreted thrust faults generally terminate within the Mancos to Above Frontier interval, and their vertical offset increases in magnitude down to the basement. Post-Mancos iii intervals are dominated by near-vertical faults with apparent normal offset.
  • Geology and Mineral Resources of Sierra Nacimiento and Vicinity, New

    Geology and Mineral Resources of Sierra Nacimiento and Vicinity, New

    iv Contents ABSTRACT 7 TERTIARY-QUATERNARY 47 INTRODUCTION 7 QUATERNARY 48 LOCATION 7 Bandelier Tuff 48 PHYSIOGRAPHY 9 Surficial deposits 48 PREVIOUS WORK 9 PALEOTECTONIC SETTING 48 ROCKS AND FORMATIONS 9 REGIONAL TECTONIC SETTING 49 PRECAMBRIAN 9 STRUCTURE 49 Northern Nacimiento area 9 NACIMIENTO UPLIFT 49 Southern Nacimiento area 15 Nacimiento fault 51 CAMBRIAN-ORDOVICIAN (?) 20 Pajarito fault 52 MISSISSIPPIAN 20 Synthetic reverse faults 52 Arroyo Peñasco Formation 20 Eastward-trending faults 53 Log Springs Formation 21 Trail Creek fault 53 PENNSYLVANIAN 21 Antithetic reverse faults 53 Osha Canyon Formation 23 Normal faults 53 Sandia Formation 23 Folds 54 Madera Formation 23 SAN JUAN BASIN 55 Paleotectonic interpretation 25 En echelon folds 55 PERMIAN 25 Northeast-trending faults 55 Abo Formation 25 Synclinal bend 56 Yeso Formation 27 Northerly trending normal faults 56 Glorieta Sandstone 30 Antithetic reverse faults 56 Bernal Formation 30 GALLINA-ARCHULETA ARCH 56 TRIASSIC 30 CHAMA BASIN 57 Chinle Formation 30 RIΟ GRANDE RIFT 57 JURASSIC 34 JEMEZ VOLCANIC FIELD 59 Entrada Sandstone 34 TECTONIC EVOLUTION 60 Todilto Formation 34 MINERAL AND ENERGY RESOURCES 63 Morrison Formation 34 COPPER 63 Depositional environments 37 Mineralization 63 CRETACEOUS 37 Origin 67 Dakota Formation 37 AGGREGATE 69 Mancos Shale 39 TRAVERTINE 70 Mesaverde Group 40 GYPSUM 70 Lewis Shale 41 COAL 70 Pictured Cliffs Sandstone 41 ΗUMΑTE 70 Fruitland Formation and Kirtland Shale URANIUM 70 undivided 42 GEOTHERMAL ENERGY 72 TERTIARY 42 OIL AND GAS 72 Ojo Alamo Sandstone
  • The Bearhead Rhyolite, Jemez Volcanic Field, NM

    The Bearhead Rhyolite, Jemez Volcanic Field, NM

    Journal of Volcanology and Geothermal Research 107 32001) 241±264 www.elsevier.com/locate/jvolgeores Effusive eruptions from a large silicic magma chamber: the Bearhead Rhyolite, Jemez volcanic ®eld, NM Leigh Justet*, Terry L. Spell Department of Geosciences, University of Nevada, Las Vegas, NV, 89154-4010, USA Received 23 February 2000; accepted 6 November 2000 Abstract Large continental silicic magma systems commonly produce voluminous ignimbrites and associated caldera collapse events. Less conspicuous and relatively poorly documented are cases in which silicic magma chambers of similar size to those associated with caldera-forming events produce dominantly effusive eruptions of small-volume rhyolite domes and ¯ows. The Bearhead Rhyolite and associated Peralta Tuff Member in the Jemez volcanic ®eld, New Mexico, represent small-volume eruptions from a large silicic magma system in which no caldera-forming event occurred, and thus may have implications for the genesis and eruption of large volumes of silicic magma and the long-term evolution of continental silicic magma systems. 40Ar/39Ar dating reveals that most units mapped as Bearhead Rhyolite and Peralta Tuff 3the Main Group) were erupted during an ,540 ka interval between 7.06 and 6.52 Ma. These rocks de®ne a chemically coherent group of high-silica rhyolites that can be related by simple fractional crystallization models. Preceding the Main Group, minor amounts of unrelated trachydacite and low silica rhyolite were erupted at ,11±9 and ,8 Ma, respectively, whereas subsequent to the Main Group minor amounts of unrelated rhyolites were erupted at ,6.1 and ,1.5 Ma. The chemical coherency, apparent fractional crystallization-derived geochemical trends, large areal distribution of rhyolite domes 3,200 km2), and presence of a major hydrothermal system support the hypothesis that Main Group magmas were derived from a single, large, shallow magma chamber.
  • (2000), Voluminous Lava-Like Precursor to a Major Ash-Flow

    (2000), Voluminous Lava-Like Precursor to a Major Ash-Flow

    Journal of Volcanology and Geothermal Research 98 (2000) 153–171 www.elsevier.nl/locate/jvolgeores Voluminous lava-like precursor to a major ash-flow tuff: low-column pyroclastic eruption of the Pagosa Peak Dacite, San Juan volcanic field, Colorado O. Bachmanna,*, M.A. Dungana, P.W. Lipmanb aSection des Sciences de la Terre de l’Universite´ de Gene`ve, 13, Rue des Maraıˆchers, 1211 Geneva 4, Switzerland bUS Geological Survey, 345 Middlefield Rd, Menlo Park, CA, USA Received 26 May 1999; received in revised form 8 November 1999; accepted 8 November 1999 Abstract The Pagosa Peak Dacite is an unusual pyroclastic deposit that immediately predated eruption of the enormous Fish Canyon Tuff (ϳ5000 km3) from the La Garita caldera at 28 Ma. The Pagosa Peak Dacite is thick (to 1 km), voluminous (Ͼ200 km3), and has a high aspect ratio (1:50) similar to those of silicic lava flows. It contains a high proportion (40–60%) of juvenile clasts (to 3–4 m) emplaced as viscous magma that was less vesiculated than typical pumice. Accidental lithic fragments are absent above the basal 5–10% of the unit. Thick densely welded proximal deposits flowed rheomorphically due to gravitational spreading, despite the very high viscosity of the crystal-rich magma, resulting in a macroscopic appearance similar to flow- layered silicic lava. Although it is a separate depositional unit, the Pagosa Peak Dacite is indistinguishable from the overlying Fish Canyon Tuff in bulk-rock chemistry, phenocryst compositions, and 40Ar/39Ar age. The unusual characteristics of this deposit are interpreted as consequences of eruption by low-column pyroclastic fountaining and lateral transport as dense, poorly inflated pyroclastic flows.
  • Ignimbrites to Batholiths Ignimbrites to Batholiths: Integrating Perspectives from Geological, Geophysical, and Geochronological Data

    Ignimbrites to Batholiths Ignimbrites to Batholiths: Integrating Perspectives from Geological, Geophysical, and Geochronological Data

    Ignimbrites to batholiths Ignimbrites to batholiths: Integrating perspectives from geological, geophysical, and geochronological data Peter W. Lipman1,* and Olivier Bachmann2 1U.S. Geological Survey, Mail Stop 910, Menlo Park, California 94028, USA 2Institute of Geochemistry and Petrology, ETH Zurich, CH-8092 Zürich, Switzerland ABSTRACT related intrusions cooled and solidified soon shorter. Magma-supply estimates (from ages after zircon crystallization, as magma sup- and volcano-plutonic volumes) yield focused Multistage histories of incremental accu- ply waned. Some researchers interpret these intrusion-assembly rates sufficient to gener- mulation, fractionation, and solidification results as recording pluton assembly in small ate ignimbrite-scale volumes of eruptible during construction of large subvolcanic increments that crystallized rapidly, leading magma, based on published thermal models. magma bodies that remained sufficiently to temporal disconnects between ignimbrite Mid-Tertiary processes of batholith assembly liquid to erupt are recorded by Tertiary eruption and intrusion growth. Alternatively, associated with the SRMVF caused drastic ignimbrites, source calderas, and granitoid crystallization ages of the granitic rocks chemical and physical reconstruction of the intrusions associated with large gravity lows are here inferred to record late solidifica- entire lithosphere, probably accompanied by at the Southern Rocky Mountain volcanic tion, after protracted open-system evolution asthenospheric input. field (SRMVF). Geophysical
  • Stratigraphic Nomenclature of ' Volcanic Rocks in the Jemez Mountains, New Mexico

    Stratigraphic Nomenclature of ' Volcanic Rocks in the Jemez Mountains, New Mexico

    -» Stratigraphic Nomenclature of ' Volcanic Rocks in the Jemez Mountains, New Mexico By R. A. BAILEY, R. L. SMITH, and C. S. ROSS CONTRIBUTIONS TO STRATIGRAPHY » GEOLOGICAL SURVEY BULLETIN 1274-P New Stratigraphic names and revisions in nomenclature of upper Tertiary and , Quaternary volcanic rocks in the Jemez Mountains UNITED STATES DEPARTMENT OF THE INTERIOR WALTER J. HICKEL, Secretary GEOLOGICAL SURVEY William T. Pecora, Director U.S. GOVERNMENT PRINTING OFFICE WASHINGTON : 1969 For sale by the Superintendent of Documents, U.S. Government Printing Office Washington, D.C. 20402 - Price 15 cents (paper cover) CONTENTS Page Abstract.._..._________-...______.._-.._._____.. PI Introduction. -_-________.._.____-_------___-_______------_-_---_-_ 1 General relations._____-___________--_--___-__--_-___-----___---__. 2 Keres Group..__________________--------_-___-_------------_------ 2 Canovas Canyon Rhyolite..__-__-_---_________---___-____-_--__ 5 Paliza Canyon Formation.___-_________-__-_-__-__-_-_______--- 6 Bearhead Rhyolite-___________________________________________ 8 Cochiti Formation.._______________________________________________ 8 Polvadera Group..______________-__-_------________--_-______---__ 10 Lobato Basalt______________________________________________ 10 Tschicoma Formation_______-__-_-____---_-__-______-______-- 11 El Rechuelos Rhyolite--_____---------_--------------_-_------- 11 Puye Formation_________________------___________-_--______-.__- 12 Tewa Group__._...._.______........___._.___.____......___...__ 12 Bandelier Tuff.______________.______________... 13 Tsankawi Pumice Bed._____________________________________ 14 Valles Rhyolite______.__-___---_____________.________..__ 15 Deer Canyon Member.______-_____-__.____--_--___-__-____ 15 Redondo Creek Member.__________________________________ 15 Valle Grande Member____-__-_--___-___--_-____-___-._-.__ 16 Battleship Rock Member...______________________________ 17 El Cajete Member____..._____________________ 17 Banco Bonito Member.___-_--_---_-_----_---_----._____--- 18 References .
  • 40Ar/39Ar Dating of the Late Cretaceous Jonathan Gaylor

    40Ar/39Ar Dating of the Late Cretaceous Jonathan Gaylor

    40Ar/39Ar Dating of the Late Cretaceous Jonathan Gaylor To cite this version: Jonathan Gaylor. 40Ar/39Ar Dating of the Late Cretaceous. Earth Sciences. Université Paris Sud - Paris XI, 2013. English. NNT : 2013PA112124. tel-01017165 HAL Id: tel-01017165 https://tel.archives-ouvertes.fr/tel-01017165 Submitted on 2 Jul 2014 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. Université Paris Sud 11 UFR des Sciences d’Orsay École Doctorale 534 MIPEGE, Laboratoire IDES Sciences de la Terre 40Ar/39Ar Dating of the Late Cretaceous Thèse de Doctorat Présentée et soutenue publiquement par Jonathan GAYLOR Le 11 juillet 2013 devant le jury compose de: Directeur de thèse: Xavier Quidelleur, Professeur, Université Paris Sud (France) Rapporteurs: Sarah Sherlock, Senoir Researcher, Open University (Grande-Bretagne) Bruno Galbrun, DR CNRS, Université Pierre et Marie Curie (France) Examinateurs: Klaudia Kuiper, Researcher, Vrije Universiteit Amsterdam (Pays-Bas) Maurice Pagel, Professeur, Université Paris Sud (France) - 2 - - 3 - Acknowledgements I would like to begin by thanking my supervisor Xavier Quidelleur without whom I would not have finished, with special thanks on the endless encouragement and patience, all the way through my PhD! Thank you all at GTSnext, especially to the directors Klaudia Kuiper, Jan Wijbrans and Frits Hilgen for creating such a great project.
  • Guidebook Contains Preliminary Findings of a Number of Concurrent Projects Being Worked on by the Trip Leaders

    Guidebook Contains Preliminary Findings of a Number of Concurrent Projects Being Worked on by the Trip Leaders

    TH FRIENDS OF THE PLEISTOCENE, ROCKY MOUNTAIN-CELL, 45 FIELD CONFERENCE PLIO-PLEISTOCENE STRATIGRAPHY AND GEOMORPHOLOGY OF THE CENTRAL PART OF THE ALBUQUERQUE BASIN OCTOBER 12-14, 2001 SEAN D. CONNELL New Mexico Bureau of Geology and Mineral Resources-Albuquerque Office, New Mexico Institute of Mining and Technology, 2808 Central Ave. SE, Albuquerque, New Mexico 87106 DAVID W. LOVE New Mexico Bureau of Geology and Mineral Resources, New Mexico Institute of Mining and Technology, 801 Leroy Place, Socorro, NM 87801 JOHN D. SORRELL Tribal Hydrologist, Pueblo of Isleta, P.O. Box 1270, Isleta, NM 87022 J. BRUCE J. HARRISON Dept. of Earth and Environmental Sciences, New Mexico Institute of Mining and Technology 801 Leroy Place, Socorro, NM 87801 Open-File Report 454C and D Initial Release: October 11, 2001 New Mexico Bureau of Geology and Mineral Resources New Mexico Institute of Mining and Technology 801 Leroy Place, Socorro, NM 87801 NMBGMR OFR454 C & D INTRODUCTION This field-guide accompanies the 45th annual Rocky Mountain Cell of the Friends of the Pleistocene (FOP), held at Isleta Lakes, New Mexico. The Friends of the Pleistocene is an informal gathering of Quaternary geologists, geomorphologists, and pedologists who meet annually in the field. The field guide has been separated into two parts. Part C (open-file report 454C) contains the three-days of road logs and stop descriptions. Part D (open-file report 454D) contains a collection of mini-papers relevant to field-trip stops. This field guide is a companion to open-file report 454A and 454B, which accompanied a field trip for the annual meeting of the Rocky Mountain/South Central Section of the Geological Society of America, held in Albuquerque in late April.
  • Geophysical Study of the San Juan Mountains Batholith Complex, Southwestern Colorado

    Geophysical Study of the San Juan Mountains Batholith Complex, Southwestern Colorado

    Geophysical study of the San Juan Mountains batholith complex, southwestern Colorado Benjamin J. Drenth1,*, G. Randy Keller1, and Ren A. Thompson2 1ConocoPhillips School of Geology and Geophysics, 100 E. Boyd Street, University of Oklahoma, Norman, Oklahoma 73019, USA 2U.S. Geological Survey, MS 980, Federal Center, Denver, Colorado 80225, USA ABSTRACT contrast of the complex. Models show that coincident with the San Juan Mountains (Fig. 3). the thickness of the batholith complex var- This anomaly has been interpreted as the mani- One of the largest and most pronounced ies laterally to a signifi cant degree, with the festation of a low-density, upper crustal granitic gravity lows over North America is over the greatest thickness (~20 km) under the west- batholith complex that represents the plutonic rugged San Juan Mountains of southwest- ern SJVF, and lesser thicknesses (<10 km) roots of the SJVF (Plouff and Pakiser , 1972). ern Colorado (USA). The mountain range is under the eastern SJVF. The largest group of Whereas this interpretation remains essentially coincident with the San Juan volcanic fi eld nested calderas on the surface of the SJVF, unchallenged, new gravity data processing tech- (SJVF), the largest erosional remnant of a the central caldera cluster, is not correlated niques, digital elevation data, and constraints widespread mid-Cenozoic volcanic fi eld that with the thickest part of the batholith com- from seismic refraction studies (Prodehl and spanned much of the southern Rocky Moun- plex. This result is consistent with petrologic Pakiser , 1980) enable reassessment and improve- tains. A buried, low-density silicic batholith interpretations from recent studies that the ment of the previous model.
  • Museum of New Mexico

    Museum of New Mexico

    MUSEUM OF NEW MEXICO OFFICE OF ARCHAEOLOGICAL STUDIES ARCHAEOLOGICAL TESTING REPORT AND DATA RECOVERY PLAN FOR TWO HISTORIC SPANISH SITES ALONG U.S. 84/285 BETWEEN SANTA FE AND POJOAQUE, SANTA FE COUNTY, NEW MEXICO James L. Moore with contributions from Jeffrey L. Boyer C. Dean Wilson Nancy Akins Mollie S. Toll Pam McBride Submitted by Timothy D. Maxwell ARCHAEOLOGY NOTES 268 SANTA FE 2000 NEW MEXICO ADMINISTRATIVE SUMMARY Between September 20 and October 18, 1999, the Office of Archaeological Studies conducted testing at two historic sites, LA 160 and LA 4968, near Pojoaque, New Mexico. Five prehistoric sites were also tested, but they are discussed in a separate document. This project was conducted at the request of the New Mexico State Highway and Transportation Department in preparation for the reconstruction of U.S. 84/285 between Pojoaque and Tesuque, Santa Fe County, New Mexico. LA 160 is on Pueblo of Pojoaque land. LA 4968 has multiple owners, including private, Pueblo of Pojoaque, and state of New Mexico. Testing was conducted to assess the extent of remains at LA 160 and LA 4968 and determine whether they can provide important information on local history. Both sites appear to have been occupied during the Santa Fe Trail period (1821 to 1880), though there may also be a Late Spanish Colonial period component at LA 4968. Cultural sheet trash deposits and a possible trash pit were found at LA 160, and LA 4968 contains at least seven structures, a well, one or more trash pits, and sheet trash deposits. Both sites have the potential to yield information relevant to local history, and further work is recommended.
  • Penitente Canyon and Elephant Rock

    Penitente Canyon and Elephant Rock

    Penitente Canyon and Elephant Rock Introduction: rocks resulting from this eruption were unusually uniform in composition. This would imply that the ash cooled as a single unit. This Penitente Canyon unit is known as the Fish Canyon Tuff. Many The canyon itself is part of the La Garita sections of the Fish Canyon Tuff are over 4,000 Caldera, a volcanic eruption that occurred in the feet thick. The area at Elephant Rocks is mainly San Juan Mountains about 26-28 million years grassland with scattered massive boulders laid ago. It is said to be the largest known explosive out. It is also habitat to the rock loving eruption in the Earth’s history, sending ash as far Neoparrya, which flourishes in igneous outcrops off as the U.S. Eastern Seaboard. The resulting or sedimentary rocks from volcanic eruptions. deposit is called Fish Canyon Tuff, which is The Neoparrya is native to the San Luis Valley volcanic ash molded together, according to and is known to exist only here and in the Wet Colville. The resulting geological formations are Mountain Valley regions. The Fish Canyon Tuff ideal for the sport of rock climbing. makes up the Elephant Rocks and gradually The La Garita Mountains are a sub-range of erodes over time to provide the proper soil the San Juans in southwest Colorado and chemistry and growth conditions in order for comprising parts of the Rio Grande and the this plant to thrive. The recreation area is 378 Gunnison National Forests. This lesser known acres with an elevation of 7,900 feet managed wilderness area in Colorado is actually one by the Bureau of Land Management.