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A Field Course
in Carbonate Geology: Ancient and Modern Carbonates
The ITEC field station at Boca del Drago, Panama, provides a truly outstanding location for the study of both ancient and modern marine carbonates and carbonate environments. The site, within a sheltered archipelago in Chiriqui Lagoon on the Caribbean coast of Panama, offers students exceptional access to the many subenvironments of a highly productive modern 'carbonate factory'. The area has been the focus of numerous recent and ongoing studies by scientists from the Smithsonian Tropical Research Institute (age dating and growth rates of Holocene corals; regional geological mapping; timing of the closure of the Isthmus of Panama, others), the University of Stuttgart (ecology and sedimentology of modern carbonate ramp systems) the Woods Hole Oceanographic Institute (coral successions and environmental change), Los Alamos National Laboratory (tropical coastal peat deposits), the University of British Columbia (coal deposition in carbonate environments; regional tectonics and sedimentation) and other institutions. Geologically, the site offers excellent exposures of Tertiary to Recent carbonate and mixed carbonate-siliciclastic deposits representing much of the history of the Limon - Bocas del Toro back-arc basin. The field course in carbonates is divided into two sections, dealing first with the several modern carbonate environments represented on this part of the high energy, microtidal Caribbean coast, and within the clear, warm waters of Chiriqui Lagoon. Upper shoreface to reef front transects of several types of shoreline are made, using snorkeling equipment. Illustrated lectures relate students' own observations to the various carbonate facies models now current. Laboratory exercises enable students to study physical and chemical attributes of modern carbonates such as primary porosity and permeability, dissolution and precipitation, early cementation, etc.. Students work in small groups during the first section of the course, and are responsible for preparing and presenting a group project to the class after 2 weeks. The second half of the course deals with the local and regional geology of the archipelago and adjacent mainland. Exposures are principally coastal, and in road cuts, and are generally excellent, despite the rapid weathering to which rocks are subject in the tropics. This is a tectonically active coast, and shoreline exposures display abundant evidence of repeated episodes of coastal uplift and subsidence, which students describe, measure and map. On the adjacent mainland, students study and map the relations between carbonates, siliciclastics and volcanics along several road transects as well as in coastal exposures. Lectures deal with field mapping techniques, and with arc-related sedimentation. After an overview of Caribbean tectonics, attention focuses on the evolution of volcanic island arcs and associated carbonate and clastic sedimentary facies in a tropical setting. Students work on their Field Notebooks, and a geological map and cross section, which are graded at the conclusion of the course. Individual projects are completed and presented to the group at the end of the course. COURSE STRUCTURE Lectures There will be formal lectures during the first 2 weeks of the course - attendance and note taking mandatory and graded. During the second week, lectures will be interspersed with discussions in which ideas and practical problems will be dealt with. The final week there will be occupied with work on individual projects. Readings and Text Text: Facies Models: Response to Sea Level Change, Roger G. Walker and Noel P. James, eds., Geological Association of Canada GeoText 1, 1992. 454 pp. The text may be purchased direct from the G.A.C. Website: www.esd.mun.ca/~gac/ Go to the Publications section at the GAC website. They offer big discounts for students. Other readings will be from recent research papers which will be provided. Lecture Topics
Field Exercises There will be a lot of coastal exploration, and lot of slogging around in water involved in this course. Students work in groups with faculty guidance and on-site lectures during the first 2 weeks as they become familiar with the area and learn mapping and sampling techniques. During this time they complete a group project, and develop proposals for individual field projects. The third week in the field will be spent working in pairs on these projects. The final week will be spent on analysis and writing of individual projects. Field Projects Individual field-based projects will comprise one third of the final grade. These may be based on the gathering and interpretation of field data, or on observation and description of local conditions related to lecture material. Breadth of enquiry is encouraged in this program, and field projects may combine geological techniques as taught in this course with relevant elements of local coral reef ecology, botany, biology, etc. if deemed appropriate by the instructor. Grading Up to 6 units of credit will be given, 3 for the lecture portion and 3 for the field work. A letter grade will be assigned based on attendance at lectures, exams, reports and research proposals. Attitude and contribution to the course will also be considered in the assignment of grades. The instructor will provide a breakdown of points earned and final letter grade to your institution. The student is to provide direct evidence of course participation such as the syllabus, schedules, handouts, lecture notes, proposals, reports, etc. Please arrange for credit through your department or academic advisor. |
