Open AccessGulf of A laska continental slope morphology: Evidence for recent trough mouth fan formation
Author(s) -
Swartz John M.,
Gulick Sean P. S.,
Goff John A.
Publication year - 2015
Publication title -
geochemistry, geophysics, geosystems
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.928
H-Index - 136
ISSN - 1525-2027
DOI - 10.1002/2014gc005594
Subject(s) - geology , continental shelf , glacier , glacial period , continental margin , last glacial maximum , oceanography , trough (economics) , geomorphology , erosion , sedimentary rock , paleontology , tectonics , macroeconomics , economics
Glaciated continental shelves are host to numerous morphologic features that help understand past glacier dynamics. Southeastern Alaska is home to the St. Elias mountains, an active orogen that also hosts temperate marine glaciers. During glacial periods ice streams advance across the continental shelf, carving shelf‐crossing troughs that reach the shelf edge. We use high‐resolution multibeam data to develop the relationship between the Yakutat and Alsek Sea Valleys and the resulting continental slope morphology. The shelf and slope geomorphology can be divided into statistical groupings that relate to the relative balance of erosion and deposition. Our analysis indicates that only the Yakutat system has been able to build an incipient trough‐mouth fan. The extreme sediment supply from this region was able to overwhelm the steep initial topography of the transform margin while further to the east sediment slope‐bypass dominates. This analysis provides an extreme end member to existing studies of temperate glaciation along continental margins. The unique interplay between rapid uplift due to ongoing collision and the massive erosion caused by temperate glaciers provides for sedimentary flux far above most other systems.