THE ROSEBEL GOLD MINE, SURINAME, SOUTH AMERICA: A NEW WINDOW TO UNDERSTAND OROGENIC EVOLUTION OF A SEDIMENTARY BASIN AND EARTH'S EARLY HISTORY

The Rosebel Gold Mine in Eastern Suriname, South America provides the first opportunity for in-depth study of the Proterozoic rocks of the Guiana shield in Suriname. The mine became operational in 2003 after exploration began in the early 1990's by Golden Star Resources and Cambior, which presently owns the mine. The information database consists of three large open pit mines, and an additional four deposits that are scheduled for mining, and exploration for new deposits. Over 200 kilometers of diamond drill core have been drilled and logged. New fresh outcrop exposures are also created outside of pits. The mine uses this information for resource assessment, mining, and exploration, but this same information provides a wealth of fresh rock to study basin evolution and develop a better understanding of Earth processes in this poorly exposed and understood region. Rosebel, as well as other mines are ideal locations to study geology.

The rocks of the Rosebel area represent a Proterozoic accretionary terrane associated with the Trans-Amazonian orogeny (2.2 - 1.9Ga). Despite the existence of general models of the crustal evolution elsewhere in the Guiana shield, there is a general lack of understanding of the evolution of the rocks in Suriname due to tropical vegetation and intense and thick weathering profiles. The core and mine outcrops provide the first fresh exposures for study. A thesis project is presently in progress to utilize a portion of this large data set.

The scope of this project is to develop an understanding of the stratigraphy of the Rosebel area by focusing on the coarser clastic sediments and volcanic units. There are at least three sequences of interest: a turbiditic, deep water sequence and two shallower water, arenitic sequences. The conglomerates of the lower arenitic sequence and upper arenitic sequence are clearly different. There are key differences in the clast populations of the two sequences. The deep water and lower arenitic sequence are auriferous, and are affected by at least two episodes of deformation. The upper arenitic sequence is not locally auriferous, and appears to be less deformed yet is also folded. This implies at least two episodes of deformation have affected the Rosebel area during the Proterozoic.