Integrated Ocean Drilling Program Expedition 341 preliminary report; southern Alaska margin; interactions of tectonics, climate, and sedimentation; 29 May-29 July 2013

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doi: 10.2204/iodp.pr.341.2014
Author(s): Jaeger, John M.; Gulick, Sean S.; LeVay, Leah J.; Slagle, Angela L.; Drab, Laureen; Asahi, Hirofumi; Bahlburg, Heinrich; Belanger, Christina L.; Berbel, Glaucia Bueno Benedetti; Childress, Laurel B.; Cowan, Ellen A.; Forwick, Matthias; Fukumura, Akemi; Ge Shulan; Gupta, Shyam M.; Kioka, Arata; Konno, Susumu; März, Christian E.; Matsuzaki, Kenji M.; McClymont, Erin L.; Mix, Alan C.; Moy, Christopher M.; Müller, Juliane; Nakamura, Atsunori; Ojima, Takanori; Ridgway, Kenneth D.; Rodrigues Ribeiro, Fabiana; Romero, Oscar E.; Stoner, Joseph S.; St-Onge, Guillaume; Suto, Itsuki; Walczak, Maureen H.; Worthington, Lindsay L.
Integrated Ocean Drilling Program, Expedition 341 Scientists, College Station, TX
Author Affiliation(s): Primary:
University of Florida, Department of Geological Sciences, Gainesville, FL, United States
Other:
University of Texas at Austin, United States
Texas A&M University, United States
Lamont-Doherty Earth Observatory, United States
Pusan National University, South Korea
Universität Münster, Germany
South Dakota School of Mines and Technology, United States
Universidade de Sao Paulo, Brazil
Northwestern University, United States
Appalachian State University, United States
University of Tromso, Norway
Nagoya University, Japan
State Oceanic Administration, China
National Institute of Oceanography, India
University of Tokyo, Japan
Kyushu University, Japan
Newcastle University, United Kingdom
Tohoku University, Japan
University of Durham, United Kingdom
Oregon State University, United States
University of Otago, New Zealand
Alfred Wegener Institute, Germany
Purdue University, United States
Instituto Andaluz de Ciencias de la Tierra, Spain
Université du Québec à Rimouski, Canada
Australian National University, Australia
University of New Mexico, United States
Source: Preliminary Report (Integrated Ocean Drilling Program), Vol.341, 192p. Publisher: IODP Management International, College Station, TX, United States. ISSN: 1932-9423
Note: In English. 210 refs.
Summary: Global climate during the Neogene is distinguished by the transition into a colder, more variable world dominated by the onset and intensification of major Northern Hemisphere glaciations. This transition to the icehouse world corresponds with a global increase in erosion rates and sediment delivery to basins. The effects of this increased erosion may be profound, as worldwide analyses of orogenic belts have shown that Earth systems cannot be considered to be the product of a series of distinct, decoupled tectonic and climatic processes. Rather, there is complex interplay between deformation, exhumation, and climate systems. Exhumation plays a key role in controlling the regional distribution of metamorphic rocks, local climate change, and development of structures throughout an orogen. As tectonic processes influence regional climate by raising mountains that enhance orographic precipitation patterns and intensity, the Neogene climate transition, in turn, likely affected tectonic processes through changes in erosion rates, which redistributed mass and subsequently altered stresses in orogenic wedges. Analytical models examining the coupling between glacial erosion and orogenic processes reveal that glacial erosion can significantly modify the patterns and rates of erosion in an orogenic wedge. A critical question is at what stage of the deteriorating Neogene climate is an orogen ultimately driven into subcriticality? Does this state lead to increased exhumation in the glaciated core of a mountain belt, enhanced topographic relief, and migration of the locus of sediment accumulation to the toes of an orogen that impacts deformation patterns? Addressing the linkages between global climate change, modification of the dynamics of surficial processes, and subsequent tectonic responses requires integrated studies of orogenic systems in areas that exemplify specific end-members of the problem. The Gulf of Alaska borders the St. Elias orogen of Alaska and Canada, the highest coastal mountain range on Earth and the highest range in North America. This orogen is <30 Ma in age, and mountain building occurred during a period of significant global climate change, allowing Integrated Ocean Drilling Program Expedition 341 to examine the response of an orogenic system to the establishment of a highly erosive glacial system. Additionally, the implications of Neogene glacial growth in the circum-North Pacific are far reaching, beyond a tectonic response to increased glacial erosion and exhumation. As climate determines the timing and patterns of precipitation, it controls glacial dynamics, erosion, and sediment/meltwater and chemical fluxes to the ocean. Establishing the timing of northwestern Cordilleran ice sheet advance-retreat cycles in southern Alaska will address a major challenge in Neogene paleoclimatology, which is to determine the extent to which glacial-age climate change was a synchronous worldwide event and what the driving mechanisms were for potentially propagating millennial-scale warming-cooling cycles around the globe. Evidence of substantial changes in surface productivity in the Gulf of Alaska since the Last Glacial Maximum indicates that millennial-scale climate change and eustasy in the northeast Pacific Ocean has a first-order effect on primary productivity.
Year of Publication: 2014
Research Program: IODP Integrated Ocean Drilling Program
Key Words: 12 Stratigraphy, Historical Geology and Paleoecology; Alaska; Algae; Biostratigraphy; Boreholes; Cenozoic; Clastic sediments; Climate change; Continental margin; Cores; Depositional environment; Diamicton; Diatoms; East Pacific; Erosion; Exhumation; Expedition 341; Foraminifera; Geophysical methods; Geophysical profiles; Geophysical surveys; Glaciation; Gulf of Alaska; IODP Site U1417; IODP Site U1418; IODP Site U1419; IODP Site U1420; IODP Site U1421; Integrated Ocean Drilling Program; Invertebrata; Lithofacies; Lithostratigraphy; Magnetostratigraphy; Marine sediments; Microfossils; Neogene; North Pacific; Northeast Pacific; Orogenic belts; Orogeny; Pacific Ocean; Paleo-oceanography; Paleoclimatology; Paleomagnetism; Plantae; Productivity; Protista; Quaternary; Radiolaria; Sedimentary rocks; Sedimentation; Sediments; Seismic methods; Seismic profiles; Seismic stratigraphy; Southern Alaska; Surveys; Tectonics; Tertiary; United States; Volcaniclastics; Well logs
Coordinates: N565800 N565800 W1470700 E1470700
N584700 N584700 W1443000 W1443000
N593200 N593200 W1440800 W1440800
N594100 N594100 W1431200 W1431200
N593000 N593000 W1440300 W1440300
Record ID: 2014053715
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