THE first two phases of a five-phased “Geological Geo-diversity Mapping on the Brazil-Guyana Border” by geoscientists from Guyana and Brazil have been successfully completed. Undertaken by the Geological Survey of Brazil (CPRM) and the Guyana Geology and Mines Commission (GGMC), the exercise followed an agreement for scientific and technical cooperation between the governments of Brazil and Guyana, signed on September 14, 2009.
The aim is the eventual production of a map showing the geological features of this hitherto unsurveyed part of Guyana, made internationally famous by Sir Arthur Conan Doyle in his book (and the subsequent blockbuster movie),“The Lost World”.
The Brazilians, who have already surveyed their corresponding side of the border, will be able to correlate geological elements on their side with Guyana’s, and unify them.
The major aim of this ground-breaking exercise is the digitization of the geological information on this remote part of Guyana, and its integration into existing maps of South America.
Head of the Guyana team, Senior Geologist Dr. Serge Nadeau, disclosed that the two phases completed to date are ARCGIS training for team members, and the major component — the geological and geo-diversity mapping and rock sampling field exercise.
The first phase of training of the team members in the use of ARCGIS software in preparation for the field work had been completed in Belem, Brazil, in 2011. The second phase, also completed recently, consisted of field geological and geo-diversity mapping and rock sampling.

Joint exercise
The teams of Brazilian and Guyanese geologists jointly mapped selected regions in the northeastern and southeastern parts of the Roraima State in Brazil, and then did field work in the southern and northern parts of Guyana, even though populations of large, vicious caimans forced some changes in the rock collection programme on the Guyana side, Dr. Nadeau said.
Ferocious caimans nothwithstanding, more than 50 outcrops were visited, and 100 rock samples were collected in Brazil and in Guyana for petrographic, geochemical and geochronological studies.
The Guyanese team did additional fieldwork mapping for two weeks, mainly in the southern parts of Guyana, to collect more samples for the project. The teams then remained in Lethem, Guyana, to do the integration of the data, sample controls, and to write the field report.
Remaining to be completed are chemical analyses of rock samples and age dating of these samples, data compilation in Belem and Georgetown, and the final report and map presentation to be made to the governments of Brazil and Guyana, and to the public.

Ancient rocks
Chemical analyses of rock samples and age dating of these rocks, some suspected to be as old as two billion years, are to be done in China, and should be completed by March. The final report and presentation of an updated geological map of the border to government officials of Guyana and Brazil, and to the public, is scheduled for June, 2012.