Late Quaternary Sea-Level Studies in Micronesia: CARMARSEL Expedition

The CARMARSEL Expedition to Guam and the Caroline and Marshall Islands has provided substantial evidence of a difference between islands in tectonically active and inactive belts. Guam has clear evidence of coral reefs that have been elevated above the present sea level, whereas the 33 islands visited in the apparently more stable belt to the east of Guam failed to show any elevated reefs. The low terraces found commonly in the Caroline and Marshall Islands all proved to be cemented rubble ramparts, with flat tops at about present high tide level. We were unable to find any coral or Tridacna in growth position, criteria we believe are necessary for postulating higher than present relative sea level. Dates on the rubble suggest formation of many of these ridges about 2500 to 3000 B.P. We conclude that there was no higher than present Holocene stand of sea level in the Caroline and Marshall Islands we visited, but that sea level was at least near to present level at the time of formation of the rubble ridges.