Research Objectives:
Many of the questions on the evolution of the East and West Antarctic Ice Sheets, antarctic climate, global sea level, and tectonic history of the West Antarctic Rift System can be answered by drilling into the floor of the Ross Sea. We will therefore conduct site surveys for drilling from the Ross Ice Shelf into the seafloor beneath. Climate data for this sector of Antarctica are lacking for the Cretaceous and Early Cenozoic. Questions include,
+ Was there any ice during the Late Cretaceous?
+ What was the antarctic climate like during the Paleocene-Eocene global warming?
+ When was the Cenozoic onset of antarctic glaciation? When did glaciers reach the coast and when did they advance onto the margin?
+ Was the Ross Sea shelf nonmarine in the Late Cretaceous? If so, when did it become marine?
Tectonic questions include,
+ What was the timing of the Cretaceous extension in the Ross Sea rift and where was it located?
+ What is the basement composition and structure?
+ Where are the time and space limits of the effects of Adare Trough spreading?
Sampling at four drill sites was completed in the early 1970s but had low recovery and did not sample the Early Cenozoic. Other drilling has been restricted to the McMurdo Sound area of the western Ross Sea, and results can be correlated for the Victoria Land Basin but not eastward across basement highs. Further, Early Cenozoic and Cretaceous rocks have not been sampled.
Our surveys (including core samples and long profiles and detailed grids over potential drilling sites) will be conducted a kilometer or two north of the ice-shelf front. In 2 to 4 years, the northward advance of the shelf will cover surveyed locations and drilling can begin. The calving of giant icebergs from the ice front in the eastern Ross Sea have exposed 16,000 square kilometers of seafloor that has been covered for decades and has therefore not been explored. We will be able to map structure and stratigraphy below unconformity RSU6 farther south and east, study the place of Roosevelt Island in the Ross Sea rifting history, and determine subsidence history during the Late Cenozoic in the far south and east. Finally we will observe current sedimentary processes beneath the ice shelf in the newly exposed areas.
