Expedition returns ready to piece together interactions between mountain building and climate history
On July 29, 2013, the scientific ocean drilling vessel JOIDES Resolution concluded Integrated Ocean Drilling Program (IODP) Expedition 341 (Southern Alaska Margin Tectonics, Climate and Sedimentation) in the port of Valdez, Alaska. By all measures, the expedition was highly successful, retrieving more than 3 kilometers of core and high-resolution logging data from five different locations along the continental margin and deep sea in the Gulf of Alaska.
Led by co-chiefs John Jaeger (U. of Florida) and Sean Gulick (U. of Texas at Austin), the international team of 34 scientists worked to better understand how long-term global climate change – particularly, the onset and growth of ice sheets and large erosive glaciers in the past 2.5 million years– can affect the growth of mountain ranges. An effective way to study this relationship is by studying sediments eroded by glaciers and deposited in the ocean.
“Although the expedition is over, our work is just beginning,” says Jaeger. “Preliminary analyses on board the ship have shown than we have some very intriguing results regarding the influence of climate on tectonics. We all can hardly wait to get back to our home institutions to really dig into the samples and test our new hypotheses.”
Because glaciers such as those found in Alaska erode and transport large amounts of rock, they can dramatically alter the landscape. Also, by rapidly decreasing the overall mass of rock in the areas they scour, they can also affect the forces that create mountain ranges – sometimes in less than a million years.
“The Gulf of Alaska is a nearly perfect location to test these ideas,” Gulick explains. “We expected to find detailed records of glacial deposition that fluctuate in accordance with the advance and retreat of glaciers and ice sheets. From what we’ve seen so far, these core samples exceed our expectations and provide critical data that were previously unavailable.“
Other goals include gaining a better understanding of the timing of the advance and retreat of the Northern Cordilleran Ice Sheet relative to other global ice sheets, obtaining a record of magnetic field reversals in the Gulf of Alaska, and a taking a look at ocean circulation dynamics and their effect on the carbon cycle during transitions into and out of ice ages. As Gulick says, “The expedition was incredibly successful at acquiring samples over the right time intervals and at a high enough time resolution to accomplish these goals.”
The Integrated Ocean Drilling Program (IODP) is an international research program dedicated to advancing scientific understanding of the Earth through drilling, coring, and monitoring the subseafloor. The JOIDES Resolution is a scientific research vessel managed by the U.S. Implementing Organization of IODP (USIO). Together, Texas A&M University, Lamont-Doherty Earth Observatory of Columbia University, and the Consortium for Ocean Leadership compose the USIO. IODP is supported by two lead agencies: the U.S. National Science Foundation (NSF) and Japan’s Ministry of Education, Culture, Sports, Science, and Technology. Additional program support comes from the European Consortium for Ocean Research Drilling (ECORD), the Australia-New Zealand IODP Consortium (ANZIC), India’s Ministry of Earth Sciences, the People’s Republic of China (Ministry of Science and Technology), the Korea Institute of Geoscience and Mineral Resources, and Brazil’s Ministry of Education (CAPES). For more information, visit www.iodp.org.
For more information about IODP Expedition 341 (Southern Alaska Margin Tectonics, Climate and Sedimentation), visit http://iodp.tamu.edu/scienceops/expeditions/alaska_tectonics_climate.html
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