Florissant Scientific Society Meeting
29 February, 2004
Speaker: Herb Meyer, paleontologist at Florissant Fossil Beds National Monument
Attendees: David Atkins, Tim and Val Brown, Bill Dexter, John Ghist, Trevor Polley, Aaron Powell, Dan Shawe, Tom Steven, Steve Veach, Andy Weinzapfel
Topic: Geology and Travelogue of Mexico, Central and South America
This broad presentation captured the varied geology, ecology, and culture, and other travelogue aspects of parts of Mexico, Costa Rica, Ecuador, Peru, Bolivia, Argentina, Chile, Brazil, and Venezuela.
A project of Florissant Fossil Beds National Monument targeting the Sierra Madre Oriental carbonate platform of NE Mexico is funded by gate receipts. It analyzes the similarities between Eocene fossils of FFBNM and living biotic communities in this part of Mexico. Partnerships include University of Arizona and University of Florida. Live plants were collected from 4 transects covering significant elevation differences from lowland tropical region to cloud forest (1200-1500 m) to the humid pine-oak forest (1700-1800m). Samples were collected up to 1 m on each side of the transect line. This was challenging due to the micro-karst topography of the area. Preliminary results of habitats showing closest similarity to Florissant suggest a mean annual temperature of 12-14 degrees C, similar to the cooler estimates that have been made previously for Florissant. As is typical of work outside the United States, many permits were required to collect and transport samples. Pollen analyses and final leaf identifications are still pending.
The second FFBNM project involves the Piedra Chamana Petrified Forest, near the village of Sexi, northern Peru. This area, discovered about 1990, is mapped as Neogene, but in reality is Paleogene (Late Middle Eocene) based on 40Ar/39Ar dating of about 39 ma. This is about 5 million years earlier than the Florissant Formation. Extremely well preserved petrified wood within tuffs at this site includes both dicots and monocots (including palms). Growth rings suggest seasonal fluctuations of the paleoclimate. A manual addressing conservation of petrified forests was written by Herb and translated into Spanish for use by the local site managers. The Peru government has recognized this important site with a postage stamp. Efforts are underway to obtain grant support to continue this project.
Some other highlights shown from Herb’s trips to Latin America include:
· Costa Rica—tremendous biodiversity, ranging from dry deciduous forest to tropical rain forest to cloud forest, generally in volcanic terrain. Some volcanoes are presently active. One interrupted JFK’s visit in 1963. Costa Rica is one of Latin America’s more progressive countries for conservation; ecotourism is emphasized.
· Ecuador, Peru, Bolivia —coastal desert, high Andes, and rain forests were visited. These include La Paz (highest international airport), Lake Titicaca (highest navigable lake), largest salt flat (Salar de Uyuni at 12,000 feet on the Altiplano), Potosi (world’s highest city and an important silver mining district), Sucre (largest Cretaceous dinosaur track site in world), and Machu Pichu.
· Chile and Argentina—glaciers of the Patagonian ice field in the southern Andes, and across the Straits of Magellan to Tierra del Fuego.
· Iguazu Falls (border of Argentina and Brazil)- by far, the most impressive series of waterfalls Herb had ever seen.
· The tepuis of Venezuela- high, remote tabletop mountains with sheer vertical cliffs, the area where Arthur Conan Doyle was inspired to write The Lost World. These 40 sq km table mountains made up of Precambrian quartzite display a very unique biotic community. Cyanobacteria coat the rocks black. A frog having African affinities can be found here. Different tepui islands display their own restricted species and endemism is high.
Next FSS meeting is scheduled for 28 March. Andy Weinzapfel will present some new ideas on the geology of Crystal Peak, the prominent pyramid-shaped feature on the official FFBNM brochure. A field trip to the Lake George Intrusive for mineral collecting is possible, but unlikely, given March is typically the snowiest month in Colorado.
Don’t miss our very own Tom Stevens being honored for his long and productive career by the Colorado Scientific Society Friday, 5 March, at 1:00-4:30 PM at the Powell Auditorium, Bldg 810 in the general area of USGS Map Sales at the Federal Center, Denver. Speakers topics will address volcanism and tectonics of the Rockies. For an updated geo-calendar of other presentations in the area, check the website http://geosurvey.state.co.us