From March 9 to 14 the MGG 541 group visited the Cibao Valley in the Dominican Republic to look at the geology and paleoecology of Caribbean Reefs in a mixed siliciclastic-carbonate setting. The trip involved 4 days of field exercises.
*Day 1 found us on the Arroyo Bellaco off the Rio Cana observing the lithofacies transition from siliciclastic sediments to a reef, the different subfacies of the reef, and contemplating the diagenetic features in the resultant deposits.
*Day 2 found us on the Rio Gurabo interpreting changes in shallow-water mixed carbonate-siliciclastic shelf deposits in the Gurabo formation.
*Day 3 was spent describing and drawing a stratigraphic section in the mixed siliclastic and reefal lithology and making a depositional interpretation of the facies and their changes.
*Day 4 was spent examining the basin fill deposits of the Mao formation in both the Rio Cana and the Rio Gurabo. The Mao formation represents a time of changing oceanographic conditions - as circulation in the Caribbean experienced final closure of the Central American Seaway and global climate underwent a transition to northern hemisphere glaciation. Locally, conditions were very favorable for reefal carbonate deposition along the basin flanks. At the top of the section in the basin records, there was possible evidence for the onset of uplift and eventual exposure. |