- 1. Amalgamation and Breakup of Pangea in the Americas.
Cosponsored by IGCP 597 (Origin and Evolution of Pangea) and IGCP 574 (Bending and Bent Orogens, Continental Ribbons).
- Brendan Murphy, St. Francis Xavier University
Jarda Dostal, Saint Mary’s University
Damian Nance, University of Ohio
There is widespread acceptance that between 300 and 200 million years ago, all of the Earth’s continental land masses were assembled into a giant supercontinent, Pangaea, surrounded by a superocean, Panthalassa. However, different configurations have been proposed, e.g. Pangaea A and B with potential solutions in Mexico. The breakup of Pangaea over the last 200 million years resulted in the formation of new oceans (such as the Atlantic, Indian and Southern) between the dispersing continental fragments. We will focus on the evolution of two types of Palaeozoic oceans whose contrasting fates were pivotal in the development of Pangaea; (a) interior oceans, such as the Rheic and Iapetus oceans which were located between converging continents and were consumed to produce Pangaea, and (b) exterior oceans which surrounded the continents during the entire Paleozoic, and became one superocean (Panthalassa) when Pangaea formed. Interior oceanic lithosphere originated between 600 and 500 million years ago and its closure produced a series of orogenic events culminating about 300 million years ago with terminal collision between Laurentia (North America) and Gondwana (South America-Africa). The late Paleozoic-early Mesozoic evolution of the exterior ocean is primarily preserved along the western margins of the Americas where episodic subduction is recorded. Mexico is an ideal locality to discuss the formation and breakup of Pangaea as: (i) competing models interpret the Paleozoic orogenic belts of southern Mexico to have formed either in the interior (Rheic or Iapetus) ocean or the exterior (Panthalassa) ocean; and (ii) there are different hypotheses for the separation of North and South America of Pangaea and formation of the Gulf of Mexico.
|Sierra Madre Oriental fold|
- T1. Silicic Volcanism.
- Cathy Busby and
Graham Andrews, University of California
This session will cover all aspects of silicic volcanism, including magma genesis, eruptive and emplacement processes, stratigraphy and structure of silicic volcanic fields, and tectonic controls on silicic volcanism.
- T2. Ore Deposits and Ore Genesis in the American Cordillera.
- Antoni Camprubi, Instituto de Geología, UNAM
From magmatic or magmatic-driven hydrothermal deposits to orogenic or orogenically emplaced deposits, the American Cordillera or 'Backbone' constitutes one of the largest and most productive regions in the world. Despite the stunning genetic type variety and economic value or potential of ore deposits in the region, formed basically since the Mesozoic, the long and complex geological history of the western Americas is yet to be unraveled in many key aspects. Ore deposits, an 'inevitable' part of such history, are no exception. This session focuses on the recent advances and studies in any type of ore deposits and their genesis in the Cordilleran scenario and neighboring areas, including the deposits that did not form in such scenario per se but are located geographically in the Cordillera (e. g., Proterozoic deposits). Magmatic arc-related deposits are the cornerstone of the metallogeny of western America, and thus it is expected that most contributions are devoted to these. However, contributions about many other ore deposit 'families' are particularly encouraged.
- T3. Convergent Margin of Western Pangea: Triassic-Jurassic Magmatism, Sedimentation, and Tectonics from Colombia to Oregon.
- Timothy Lawton, New Mexico State University
Rafael Barboza-Gudiño, Universidad Autónoma de San Luis Potosí, México
Roberto Molina-Garza, Centro de Geociencias, UNAM
A geographic swath of Upper Triassic-Upper Jurassic pyroclastic, volcanic and sedimentary rocks defines the mid-Mesozoic continental margin of western Pangea. Commonly assigned to the Cordilleran and Nazas arcs and subsequent rift or transtensional basins, the origin and role of these volcanic and sedimentary successions in the evolution of the American Cordillera remain debated. We invite researchers interested in the sedimentology, volcanology, geochronology and general tectonics of this succession to participate in a session designed to integrate the current state of knowledge pertaining to the geology of the active margin of western equatorial Pangea.
- T4. Flat-Slab Subduction from Past to Present.
- T5. Mechanisms of Arc Magma Generation along the Cordillera.
- Laura Mori, Instituto de Geología, UNAM
Peter Schaaf, Instituto de Geofísica, UNAM
Arturo Gómez Tuena, Centro de Geociencias, UNAM
This session seeks to examine the igneous varieties along the American convergent margin, with the aim of achieving a better understanding of the origin and evolution of Cordilleran magmatism. We encourage contributions that use geochemical and petrological approaches as well as modeling studies to address broad questions concerning igneous petrogenesis. Topics of interest include: identification of mantle sources, subduction components and intracrustal processes involved in the generation of the Cordilleran continental crust; the relationship between geochemical diversity of arc magmas, basement geology and subduction geometry; magmatic manifestations of crustal recycling via delamination or subduction erosion; and petrological connections between the exposed plutonic sections and the volcanic products of the Cordilleras.
- T6. Terrane Accretion, Flat Slab Subduction, and Convergence Rate Variations: What Caused the Cretaceous-Paleogene Shortening across the Mexican Cordillera?
- Michelangelo Martini and Elisa Fitz Díaz, Instituto de Geología, UNAM
Timothy Lawton, New Mexico State University
The Mexican Fold-Thrust Belt (MFTB) is a prominent tectonic feature that developed along eastern Mexico during Late Cretaceous shortening. Based on correlations with the US Cordillera, terrane accretion, flat slab subduction, and variations of the convergence rate have been proposed preliminarily as the possible causes for the MFTB. However, none of these scenarios have been analyzed in detail. Contributions exploring the tectonic mechanisms that led to the development of the MFTB are welcomed in this session.
- T7. Structural Style, Timing, and Stratigraphy of the Laramide Orogeny in Mexico.
- Mariano Cerca, Centro de Geociencias, UNAM
Gabriel Chavez-Cabello, Universidad de Nuevo León
Martín Valencia, Instituto de Geología, UNAM; Martin Valencia, UNAM
We encourage contributions addressing the shortening deformation associated to the Laramide orogeny in Mexico and the Cordillera. The integration of diverse approaches can lead to a better understanding of the shortening that took place during this important orogeny that contributed to shape the cordillera. Studies addressing the geographic extent of the orogeny, timing of initiation and termination, and history of deformation are welcomed. Contributions discussing the paradigms for the causes and effects of the Laramide orogeny and its contextual framework within the Cordilllera are strongly encouraged. Mineral resources related to what has been called the “Laramide intrusives” can place important constraints to Laramide models and are also welcomed.
- T8. Lithosphere Stretching and Magmatism Leading to the Gulf of California.
- Luca Ferrari, Centro de Geociencias, UNAM
Arturo Martin Barajas, CICESE
Joann Stock, California Institute of Technology
The creation of new oceanic lithosphere in the Gulf of California oblique rift was preceded by at least 20 Ma of extensional tectonics and dominantly bimodal magmatism that partly occurred during the final phase of subduction of the Farallon plate. In this multidisciplinary session we aim to discuss this long process that culminated in the present Gulf. Some key issues concern the age and the amount of strike-slip motion accommodated within the Gulf, the role of the pre-existing lithospheric structures and previous magmatic episodes in the localization of the rift, and the causes of the magmatic and tectonic segmentation of the Gulf. We especially encourage contributions on the kinematics and age of extensional and transtensional basins, physical and numerical modeling of the rifting process, and the petrogenesis of magmatism. Any geologic and geophysical contribution on the Gulf and adjoining regions of Baja California and the Sierra Madre Occidental is also welcomed.
- T9. What Fossil Ages and Distributions Tell Us about the History of the Ancient Gulf of California?
- Judy Terry Smith, Smithsonian Institution, National Museum of Natural History
Judith Smith and Ana Luisa Carreño, Instituto de Geología, UNAM
Javier Helenes, CICESE
Many scientists who model the evolution of the Gulf of California think the ancient Gulf is considerably younger than the late Middle Miocene age suggested by reworked microfossils. Many fossils from the northern gulf, including the Salton Trough of California, are Tertiary Caribbean species also found in Miocene rocks from Trinidad to Panamá, and Costa Rica to Perú. This session aims to take a fresh look at data based on specimens, not published lists, to discover new insights on the age of the earliest seawater. Contributions on corals, echinoids, mollusks, microfossils, other invertebrates and vertebrates are encouraged.
- T10. The Caribbean Plate and its Geologic Connections with North and South America.
- Luigi Solari, Centro de Geociencias, UNAM
Uwe Martens, Tectonic Analysis Ltd.
Geological correlations and the geodynamic evolution of southern Mexico, Central America, the Caribbean region, and the northern Andes continue to be topics of widespread and active research, multidisciplinary interest, and ongoing controversy. Geologic investigations of these areas are critical for refining reconstructions of Pangea, understanding the origin of the Caribbean plate, and evaluating tectonic models that account for the opening of the Gulf of Mexico, the separation of the Americas, and the relative migration history of the Caribbean. We welcome contributions in all fields of Earth Sciences that yield constraints on the geologic evolution of these areas, especially those that allow regional and continental correlations and constrain the geodynamic evolution.
- T11. Developments in Geophysical Investigations of Volcano Hydrothermal Systems: Exploration and Hazards.
- Jonathan M.G. Glen and Shaul Hurwitz, USGS
Vyacheslav M. Zobin, Universidad de Colima
Robert A. Sohn, Woods Hole Oceanographic Institution
Areas of the continental crust characterized by high heat flow and subsurface circulation of multiphase and multi-component aqueous and gas-rich fluids are both a source of hazard (e.g., hydrothermal explosions and induced seismicity) and a resource (e.g., geothermal energy and mineral deposits). Seismic, electric, and potential field methods and heat flow studies could provide useful spatial and temporal information on the structure, seismicity, phase distribution, and processes within these systems. We enourage contributions that present results from studies where geophysical and seismological methods have elucidated processes in active and fossil volcano-hydrothermal systems and have helped mitigate hazards and guide geothermal and mineral exploration.
- T12. Limnogeology Studies and Paleoenvironmental Records from Ancient and Modern Lakes.
- Beatriz Ortega and Margarita Caballero, Instituto de Geofísica, UNAM
Socorro Lozano, Instituto de Geología, UNAM
Lacustrine sediments are valuable archives of: i) terrestrial climate and environmental change, ii) tectonic and volcanic activity, and iii) human impact. Lake records can provide insights into short or long-term changes in temperature, precipitation, erosion rates, vegetation changes, etc., which can be related with changes in atmospheric circulation and other forcing mechanisms. This session aims to bring together limnogeologists working on any discipline or field of knowledge, on records covering all time and space scales, either on basic or applied research.
- T13. Heterogeneous Geologic Formations: Modeling Spatial Variability.
- Eric Morales Casique, Instituto de Geología, UNAM
Martín Díaz Viera, Instituto Mexicano del Petróleo
Many science and engineering problems require a three-dimensional description and representation of geologic formations. However, 3D models are hindered by data scarcity and interpolation errors. We encourage presentations that address methods to integrate field data in the 3D reconstruction of geologic formations and evaluate the uncertainty associated which such reconstruction. We also welcome analyses on the effect of spatial variability on hydrogeologic and oil reservoir processes.
- T14. Ground Deformation Related to Anthropogenic Activities: Achievements in the Development of Geoscience Information System for Improved Management of Natural Resources.
- Dora Carreon-Freyre and Mariano Cerca, Centro de Geociencias, UNAM
Devin Galloway, USGS
Penelope Lopez-Quiroz, Centro de Investigación en Geografía y Geomática
Deformation of the near surface and deep geological sequences can be associated with natural and anthropogenic phenomena. The intensive exploitation of subsurface natural resources and the urbanization of areas nearby steep slopes cause mechanical instabilities that are shown in the surface as land subsidence, ground fracturing, and landslides. We encourage the Earth Sciences and Engineering communities to share innovative case studies and methodologies for the development of geoscientific information systems integrated by the monitoring of generalized deformation, modeling and characterization achievements. Case studies highlighting the transfer of geoscientific information to stakeholders and decision-makers concerned with the management of these natural resources are also welcomed.
- T15. Pushing the Envelope: Recent Advances in Teaching Geoscience with Technology.
- T16. Undergraduate Research Posters.
Cosponsored by Council on Undergraduate Research (CUR).
- Kathleen D. Surpless, Trinity University
Submissions to this session will highlight undergraduate student research contributions to the varied geoscience subdisciplines. Student research results from National Science Foundation–Research Experiences for Undergraduates (NSF REU) and similar programs are welcome. Posters only.
- T17. Environmetal Geochemistry.
- Mario Villalobos; Laura Beramendi; Francisco Romero; Priyadarsi Roy; Ofelia Morton
In recent years the application of geochemical tools has acquired significant importance in evaluating and solving a wide range of problems encountered in present day environmental settings, as well as in understanding past climatic conditions in different parts of the world. Environmental geochemistry has thus become a widely interdisciplinary field, as other scientific and engineering disciplines have been increasingly incorporated. In this broad-themed session we seek contributions from geoscientists of different areas with interests in applying geochemistry to describe and understand the behavior of environmental systems. The topics considered in this session are broad and include: hazardous waste management; soil, water and air pollution; environmental health risk assessment; remediation and reclamation of contaminated sites; past climatic changes registered in both, marine and continental archives at different time-scales; environmental aqueous geochemistry at scales ranging from field to microscopic, including investigations on environmental nanoparticles and molecular processes.