To submit additional field trip proposals, contact Jorge Aranda.
- Trip 4.
Sierra de Catorce: Remnants of the Ancient Western Equatorial Margin of Pangea in Central Mexico.
- Sun.–Tues., 25–27 March. Cost: US$520.
José Rafael Barboza-Gudiño, Universidad Autónoma de San Luis Potosí, rbarbozauaslp.mx; Roberto S. Molina-Garza, Centro de Geociencias, UNAM; Timothy F. Lawton, New Mexico State University.
This field trip begins and ends in San Luis Potosí (~200 km north of Querétaro). Participants will explore turbiditic and wildflysh sequences of a triassic submarine fan system (Potosí Fan) or Upper Triassic Zacatecas Formation, and volcanic successions of the Lower Jurassic volcanic arc of western North America in north-central to northeastern Mexico (“Nazas Arc”). Both paleogeographic elements, outcropping in the Mesa Central province, are linked to the ancient western equatorial margin of Pangea during the early Mesozoic time. The trip will examine also the Middle to Upper Jurassic continental fining upward succession (La Joya Formation) and transgressive Upper Jurassic-Cretaceous cover exposed in the Sierra de Catorce uplift, including their stratigraphic and tectonic relations. Several stops will show sampling sites of new geochronologic data, which have implications for tectonic and paleogeographic reconstruction of central and northeastern Mexico. Field trip ends on March 27 in San Luis Potosí at 18:00, but participants have the option to stay in San Luis Potosí that night at own expense and travel on March 28 with the field trip leaders to Juriquilla with a stop at the spectacular La Joya Honda maar, arriving in time for the opening reception. No additional cost will be charged for this optional trip.
- Trip 5.
Late Pleistocene Rhyolitic Explosive Volcanism at Los Azufres Volcanic Field, Central Mexico.
- Sun.–Tues., 25–27 March.
- Trip 7.
Geology and Tectonics of the Southeastern Portion of the Sierra de Guanajuato.
- Sun.–Tues., 25–27 March. Cost: US$380. José Jorge Aranda-Gómez, UNAM, jjaggeociencias.unam.mx; Pablo Dávila-Harris; Luis Vassallo.
Sierra de Guanajuato is located in central México in a region where several major geologic and tectonic provinces join. Rocks exposed in the Mesozoic basal complex are keys to understand the Guerrero terrane concept and the evolution of the southern part of the North America craton during the early Cretaceous. A Tertiary volcano-sedimentary succession, uncomfortably resting on top of the basal complex, includes one of the best documented continental red bed deposits in central México, which was accumulated immediately after the end of the Laramide orogeny and records the earliest pulses of extension in the region. Resting atop the red beds is a volcanic succession genetically related to the Oligocene activity of Sierra Madre Occidental volcanic province. World-class silver deposits that have been exploited for nearly four centuries are hosted in the Tertiary volcano-sedimentary succession, as well as in the rocks of the basal complex. The rocks of the basal complex and regional tectonic features are the focus of the first day of the field trip and the last two days are devoted to the study of the nature and probable source of the volcanic rocks, which immediately preceded the ore deposition along two conspicuous sets of normal faults.
- Trip 3.
Environmental Geochemistry of the Pozos Mining District, Guanajuato, East-Central Mexico.
- Wed., 28 March. Cost: US$80.
Alejandro Carrillo, UNAM, ambientegeociencias.unam.mx; Juventino Martínez, Gilles Levresse.
The participants will explore the Mining District of Mineral de Pozos and its environmental aspects (mine tailings deposited without any environmental concern whatsoever). This historical mining site is one of the oldest in Mexico, beginning in the 1600´s. The exploitation was focused on silver and gold in the sulfur-rich epithermal veins hosted by deformed Jurassic and Cretaceous sedimentary rocks. The site was abandoned by early 1940´s, with a "Bonanza" between 1892 and 1897. We will visit several ancient exploitation “Haciendas”, which look more as ”ghost places”, than exploitation plants. Have your camera ready for “shoots into the past” from this, once very active and economical center of central-east Mexico. The field trip is one full day from 7 am to 7 pm. The field trip will include lunch, and will start, and end, at the lobby of Hotel Mision Juriquilla, Querétaro.
- Trip 1.
Late Paleozoic–Early Mesozoic of the Acatlán and Ayu Complexes, Southern Mexico: Events on the Periphery of Pangea Synchronous with Amalgamation and Breakup.
Co-sponsored by IGCP 597: Amalgamation and Breakup of Pangea.
- Sat.–Wed., 31 March–4 April. Cost: US$588.
Duncan Keppie, Instituto de Geología, UNAM; Brendan Murphy, Gonzalo Galaz, Moritz Kirsch, and Maria Helbig.
Field trip starts in Querétaro and ends either at a Mexico City airport hotel (night of the 3rd April – plan to fly out on the 4th April) or at Querétaro airport at noon on the 4th April. This field trip in the Acatlán Complex of southern Mexico will examine the geological record of an orogen on the western periphery of Pangea: 1) Triassic-Jurassic deposition of a clastic sequence intruded by tholeiitic mafic dikes that underwent high-grade metamorphism and migmatization and exhumation on the western margin of Pangaea; 2) Late Carboniferous – Early Permian synchronous arc magmatism and pull-apart basin sedimentation followed by Triassic thrusting on the western periphery of Pangaea; 3) A Devonian-Permian sequence synchronous with Carboniferous extrusion of high-pressure rocks into the upper plate above a subduction zone on the western periphery of Pangaea.
- Trip 8.
Recent Volcanism and Hazards at the Eastern Trans-Mexican Volcanic Belt.
- Sat.–Mon., 31 March–2 Apr.
- Trip 6.
Ground Deformation Related to Anthropogenic Activities in Urbanized areas of the Mexico Basin.
- Sun.–Mon., 1–2 April.
- Trip 2.
The Late Cretaceous Mexican Fold-and-Thrust Belt and its Possible Relation with the Accretion of the Guerrero Terrane.
- Sun.–Tues., 1–3 April. Cost: US$344.
Michelangelo Martini, mmartinigeologia.unam.mx; Elisa Fitz, Timothy Lawton.
The fieldtrip will provide a comprehensive overview of the Mexican Fold-Thrust Belt (MFTB) in the Sierra Madre Oriental of central Mexico, and the possible suture belt of the Guerrero Terrane in the Sierra de Guanajuato. During the first two days we will visit the Sierra Gorda and Tolimán area in Querétaro state with spectacular landscapes, and excellent exposure of the MFTB structures. Aspects on the regional structure, syn-tectonic sedimentation, deformation style, shortening gradients, temperature and timing of deformation will be addressed during the first day of the field-trip. During the second day we will observe changes in the Cretaceous stratigraphy and structure as we move to the western edge of the MFTB in the Tolimán area. We will discuss the tectonic setting of the Tolimán rocks and of their secondary structures. During the third day of the trip we will move to the Guanajuato area, where we have the opportunity to observe the suture belt between the Guerrero and Sierra Madre terranes. This belt is a ~70 km-wide deformation zone, where continent-recycled meta-sedimentary rocks of the Sierra Madre terrane overthrust arc-recycled meta-sedimentary rocks of the Guerrero Terrane. Based on the fieldtrip geologic observations we can discuss the possibility that the Guerrero Terrane accretion triggered the Late Cretaceous MFTB of the Sierra Madre Oriental.
- Trip 9.
Geology and Geochronology of Tláloc, Telapón, and Iztaccíhuatl Volcanoes, Sierra Nevada, Central Mexico.
- Sun.–Wed., 1–4 April.