Arizona Geological Society


Upcoming events

    • 03 Oct 2017
    • 6:00 PM - 9:00 PM
    • Sheraton, 5151 E Grant Rd. (& Rosemont), Tucson AZ 85712

    Sponsored by:    Skyline Assayers and  Laboratories

    Andean River Sediments as a Window into the Tectonic History of Ecuador

    by Lily J. Jackson, PhD. Candidate, University of Texas at Austin

    Abstract:  The Andes of South America form the longest mountain range on Earth spanning over 7000 km. In contrast to much of the Andes, the tectonic history of the Ecuadorian segment involves one or many accretionary events with proposed timing ranging from the Late Cretaceous to the Eocene. Additionally, Ecuador’s two Cordilleras (Eastern Cordillera and Western Cordillera) may have been among the most recent segments of the Andes to attain high topography, though the age of the Cordilleras remains debated. Topographic growth causes erosional unroofing, producing detritus that is then deposited adjacent to the growing mountain belt and incorporated into the sedimentary record of the event. Modern river sediments faithfully represent the outcrop geology within their catchments. Pairing detrital zircon U-Pb geochronology of river sands with quantitative GIS models of surface geology allows for interpretation of sediment provenance within river catchments. In Ecuador, we find that various morphotectonic regions have diagnostic U-Pb age spectra that reveal erosion and sediment transport related to key tectonic events. Morphotectonic provinces of Ecuador include the: (1) Late Cretaceous-Cenozoic sub-Andean and Oriente retroarc foreland basin; (2) Eastern Cordillera; (3) Interandean Valley; (4) Western Cordillera; and (5) forearc lowlands and coastal plain. In the Oriente foreland basin, Cretaceous-Neogene sediments are the dominant surface exposures, with Jurassic arc-related rocks restricted to the sub-Andean Zone. Diagnostic U-Pb age spectra for these foreland zones contain Jurassic, Triassic, and Cretaceous age peaks. In contrast, Eastern Cordillera exposures are metamorphosed Paleozoic-Mesozoic rocks and non-metamorphosed Triassic-Jurassic igneous intrusions. Diagnostic U-Pb age spectra for the Eastern Cordillera contains large age populations of Proterozoic and Paleozoic ages representing recycled cratonic material. Western Cordillera surface geology involves Late Cretaceous basement rocks, Cretaceous-Paleogene sedimentary rocks and Cenozoic volcanic cover. Diagnostic U-Pb age spectra for the Western Cordillera contain Neogene-Quaternary age populations with minor Triassic and Cretaceous ages. River samples draining Paleogene units in the easternmost Western Cordillera show Proterozoic and Paleozoic ages indicative of exhumation, erosion, and westward transport of detritus from the Eastern Cordillera. Furthermore, the dominant Proterozoic and Paleozoic ages that characterize the Eastern Cordillera rivers provide support for multiple recycling events prior to the current tectonic configuration of the Ecuadorian Andes.

    Bio:  Lily Jackson is a Ph.D. Candidate at the University of Texas at Austin in the Jackson School of Geosciences and a National Science Foundation Graduate Research Fellow. Lily is a native Arizonan from Prescott. She graduated magna cum laude with a Bachelor of Science from the University of Arizona in 2014. While in Tucson, Lily was the recipient of the Arizona Geological Society Scholarship Award in 2013, and served as a Student Councilor to the AGS executive committee in 2014. Lily was named the outstanding senior in Geosciences for her graduating class.

    Lily’s research focuses on the Cenozoic tectonic history of northern Peru and Ecuador. Lily uses sedimentary basin analysis, detrital zircon U-Pb geochronology, stable isotope geochemistry, and field geology in her research.

    • 07 Nov 2017
    • 6:00 PM - 9:00 PM
    • Sheraton, 5151 E Grant Rd. (& Rosemont), Tucson AZ 85712

    Sponsored by:    Major Drilling Group International, Inc.

    Overview of Carbon and Carbon Dioxide

    by Eric Sundquist, U.S. Geological Survey



    • 05 Dec 2017
    • 6:00 PM - 9:00 PM
    • Sheraton, 5151 E Grant Rd. (& Rosemont), Tucson AZ 85712

    Sponsored by:   Available

    The Ocean's Role in Climate of the Anthropocene

    by Jollen Russell, University of Arizona



    • 02 Jan 2018
    • 6:00 PM - 9:00 PM
    • Sheraton, 5151 E Grant Rd. (& Rosemont), Tucson AZ 85712

    Sponsored by:   Available

    How Two Distinctly Different Types of Volcanism have Driven Climate Change throughout Earth's History

    by Peter Ward, Retired U. S. Geological Survey



Past events

05 Sep 2017 Vic Baker presents The Influence of the 18th Century Enlightenment on the Natural Sciences
22 Aug 2017 AGS Meet and Greet, A Networking Event
11 Jul 2017 Andrew Zaffos presents Global Tectonics and Marine Animal Diversity
06 Jun 2017 Dan Johnson presents Introduction to the Florence Copper Project and In-Situ Copper Recovery
02 May 2017 Robert Glennon presents America's Water Crisis and What To Do About It
22 Apr 2017 Spring Field Trip - The Laramide-age Chilito Porphyry Copper Deposit
04 Apr 2017 David London presents The Nature and Origins of Internal Zonation within Granitic Pegmatites
07 Mar 2017 Derek J. Thorkelson presents The Precambrian Tectonic Connection between Yukon and Arizona
07 Feb 2017 Daniel Hummer presents Mineral ecology and evolution: Using large datasets to tell the story of the co-evolution of Earth and life
03 Jan 2017 David A. Sawyer presents Dating Geologic Time in the Cretaceous: Integrating Biostratigraphy, Isotope Geochronology, and Astrochronology in Sedimentary Deposits of the Cretaceous Western Interior Seaway
06 Dec 2016 John W. Ewert presents USGS Responses to Some Volcanic Crises and Eruptions Around the World
01 Nov 2016 Alexander Schauss presents Minerals, Trace Elements and Human Health
22 Oct 2016 Fall Field Trip - The Peach Spring Tuff and the Silver Creek Caldera, Northwestern Arizona
04 Oct 2016 Hamish Martin Presents Geology of the Resolution Cu-Mo Deposit, Superior Arizona
06 Sep 2016 Keith R. Long Presents No Bonanza from Cheap Oil
02 Aug 2016 Lee Allison Presents The Future of State Geological Surveys: the Arizona Case Study
05 Jul 2016 Don Applebee Presents Genesis of the Chilito Porphyry Copper Deposit
07 Jun 2016 Robert Hildebrand Presents Collisions, Slab Failure Magmatism and the Development of Cordilleran Batholiths
03 May 2016 Peter Modreski will present "Pegmatites: Mineralogy, Gemstones, Economic Geology, and maybe not quite the same Giant-Crystal Rocks you always thought they were"
30 Apr 2016 Spring Field Trip - An Introduction to the Pinal Schist in Southeastern Arizona
05 Apr 2016 Jordon Bright Presents Looking for an Ocean in the Desert, the Enigmatic Bouse Formation
01 Mar 2016 Peter R. Johnson Presents Tectonics and Mineral Deposits of the Arabian-Nubian Shield
02 Feb 2016 Dr. Karen Wenrich Presents The Ga-Ge Rich Apex Mine, Utah - A Tsumeb, Namibia Analogue
05 Jan 2016 Sarah Baxter Presents Calc-silicate Alteration and Ore Characterization, ASARCO Mission Complex, Pima County, Arizona
01 Dec 2015 Peter Smith Presents The Latest News from Mars
14 Nov 2015 Fall Field Trip - Northern Plomosa Mountains and Bouse Formation in Blythe Basin
03 Nov 2015 Karen Kelley presents The Giant Concealed Pebble Cu-Au-Mo Porphyry Deposit, Southwest Alaska
06 Oct 2015 Caleb King presents Eocene Hydrothermal Systems and Contrasting Hydrothermal Alteration in the Battle Mountain District, Nevada
01 Sep 2015 Carl Bowser presents The Genesis of the Kramer Borax Deposit, Rogers Lake, Mojave Desert, CA:
04 Aug 2015 Dan Lynch presents Volcanoes in the Back Yard
07 Jul 2015 Erik Melchiorre presents The Complex Geological History Recorded by Arizona Placer Deposits:
02 Jun 2015 Jan C. Rasmussen Presents - Arizona Mineralization through Geologic Time
05 May 2015 Gordon Haxel Presents - Alpine peridotite in the desert - Arizona's Laramide subduction complex
02 May 2015 Spring Field Trip - Oak Creek - Mormon Lake Graben
18 Apr 2015 Third Annual Arizona Geological Society Doug Shakel Student Poster Event
03 Mar 2015 Apollo 17 Astronaut and Former Senator Harrison H. Schmitt presents A Geological Visit to a Valley on the Moon
03 Feb 2015 Don Yurewicz Presents Assessing Unconventional (Continuous) Hydrocarbon Resource Plays
06 Jan 2015 Arend Meijer presents: Sulfide-rich Proterozoic Mafic Rocks and Arizona Porphyry Copper Deposits - A Connection?
02 Dec 2014 Victor R. Baker: Megafloods on Earth, Mars, and Beyond
15 Nov 2014 Fall Field Trip - Debris Flows Shape the Sabino Canyon Landscape - look out below!
04 Nov 2014 Isabel F. Barton: Historical Development & Current State of Geological Research in the Central African Copperbelt
07 Oct 2014 Apollo 17 Astronaut and Former Senator Harrison H. Schmitt presents A Geological Visit to a Valley on the Moon
02 Sep 2014 Lewis Land presents Evaluation of Groundwater Residence Time in a Karstic Aquifer System
05 Aug 2014 Jamie Molaro presents Thermal Stress Weathering in the Inner Solar System
01 Jul 2014 Jim Leenhouts presents Surface-water/groundwater Interactions in Arizona
03 Jun 2014 Arend Meijer presents Pinal Schist of So. Arizona--A Paleoproterozoic Fore-Arc Complex
06 May 2014 John C. Lacy presents The Genesis of Mining Law
26 Apr 2014 Spring Field Trip - Geology of the Christmas Porphyry Copper Deposit
24 Apr 2014 Second Annual Arizona Geological Society Doug Shakel Student Poster Event
01 Apr 2014 Eric Seedorff presents, Structural Dismemberment of a Porphyry Molybdenum System, Spruce Mountain District, Northeastern Nevada
04 Mar 2014 John Dreier presents, Copper Deposits of the Coast Ranges of Chile; A trip through time, space, and ore deposit nomenclature
04 Feb 2014 Ralph Stegen presents The Morenci Porphyry Cu-Mo Deposit, Greenlee County, Arizona: A Geologic Summary with Emphasis on Hypogene and Supergene Mineralization
07 Jan 2014 Steve Castor presents, Mountain Pass and other North American Rare Earth Element Deposits
03 Dec 2013 Stephen Jackson, USGS, Looking forward from the past: Ecological impacts of climate change through the lens of history
05 Nov 2013 Malcolm Siegel, PhD, MPH, LJS Consulting, Inc and School of Medicine, University of New Mexico, Albuquerque, NM. 87047: Uranium Mining in the American Southwest: Can Medical Geologists Ask the Right Questions?
04 Oct 2013 Field Trip - H. Wilson Sundt Generating Station
01 Oct 2013 Mark Logsdon, Principal Geochemist, Geochimica, Inc.: What Does “Perpetual” Management and Treatment Mean? Toward a Framework for Determining an Appropriate Period-of-Performance for Management of Reactive, Sulfide-Bearing Mine Wastes
01 Oct 2013 Mark J. Logsdon, Geochimica, Inc., Does acid-rock drainage lead to waste-rock instability? Geological, hydrological, and geochemical framework for the Questa Mine
03 Sep 2013 Pete Reiners, UA, Geosciences Dept., Geochronology of secondary Fe & Mn oxides in bedrock
30 Aug 2013 Field Trip - University of Arizona Tree-Ring Research Laboratory
06 Aug 2013 Bill Stavast, Freeport-McMoRan Copper & Gold, The Safford Mine: What we have learned since production began
02 Jul 2013 Lukas Zurcher, USGS, presents: "Tectono-magmatic evolution of the Central Tethys Region"
04 Jun 2013 Steve Van Nort presents, "Gold Fever! The BRE-X/Busang Story
07 May 2013 Federal lands and mineral resources: Colorado Plateau uranium deposits and the Sonoran Desert Heritage
18 Apr 2013 First Annual Arizona Geological Society Doug Shakel Student Poster Event

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