Friday, April 4, 2014

The FORCE Expeditions (Ford Ranges Crustal Exploration) 1989-90, 1990-91

Tucker, Steve, Cain, Dave, Bruce and Christine, Put-In day to Ford Ranges.
Photo © Bruce Luyendyk   
White Ocean of Ice deals with investigation of plate tectonic history in the Southwestern Pacific. Our team of geologists sought out information on the separation of the New Zealand subcontinent on the Pacific Plate from the main continent of Antarctica – the Antarctic Plate. The result of that separation created the modern South Pacific Ocean basin.

We knew from oceanographic studies that this sea floor had formed since about 80 million years ago but we did not know how and when that process started and led to the drifting of New Zealand away from West Antarctica. Research in New Zealand by members of our team and many others revealed some facts, but did they match observations is Antarctica? Those were few and difficult to make. We decided to go to Antarctica to find answers to these questions. The U.S. National Science Foundation supported our research.

Our work focused in the Ford Ranges of Marie Byrd Land in West Antarctica, a location that was believed once joined with New Zealand. We learned from several lines of evidence that the whole process of plate breakup brewed for more than twenty million years. It began close to 105 million years ago before separation took off.

We also studied a very special variety of metamorphic rocks (rocks transformed by intense heat and pressure) in the Fosdick Mountains of the Ford Ranges. We found that these rocks had been exhumed from many miles deep in the Antarctic crust as the plate breakup process got underway. This was a result of stretching between the plates. Upper levels of crust thinned and allowed the lower levels to rise up and create the mountains. Research in this mountain range continues today by geologists at Colorado College.

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