TY - JOUR
T1 - Mass transport processes in the southern Scotia Sea
T2 - Evidence of paleoearthquakes
AU - Ruano, Patricia
AU - Bohoyo, Fernando
AU - Galindo-Zaldívar, Jesús
AU - Pérez, Lara F.
AU - Hernández-Molina, F. Javier
AU - Maldonado, Andrés
AU - García, Marga
AU - Medialdea, Teresa
N1 - Publisher Copyright:
© 2014 Elsevier B.V.
PY - 2014/12/1
Y1 - 2014/12/1
N2 - The southern margin of the Scotia Sea hosts the convergent boundary between the Scotia and Antarctic plates where a number of small basins are situated. Mass transport deposits (MTDs) within two of these small basins, Dove and Scan basins, reveal the importance of seismicity, slope instabilities and depositional processes in their growth patterns. Swath-bathymetry and very high-resolution seismic data show that there are over 200 MTDs in these basins in the last 100 ky record. MTD characterizations are determined on the basis of their regional distribution, shape, apparent size and depth. Their sedimentary and tectonic implications are discussed, as well as the evidence of different triggering mechanisms in this region, which is characterized at present by moderate-to-high magnitude, shallow to intermediate earthquakes. MTDs are more abundant in the Dove Basin (with lenticular and wedge shapes), suggesting that this basin was affected by active tectonics to a greater degree than the Scan Basin. This finding is significant in the overall evolutionary context of the Scotia Sea region and Scotia-Antarctic plate geodynamics. Nevertheless, other factors -volcanic activity, vigorous bottom-currents, and/or higher sedimentation rates - must also be considered for the generation of MTDs in the Scan Basin, where a variety of processes generated more diverse MTD morphologies. Paleoseismological estimations of the repeated occurrence of wedge shaped MTDs in contact with fault scarps point to potential sources of large magnitude (Mw ~. 7.2-7.3) paleoearthquakes in several sites, in agreement with the present high magnitudes of regional seismicity. This study shows MTDs to be appropriate as paleoearthquake indicators in active tectonic settings. The distribution of MTDs in the southern Scotia Sea has important implications for geodynamic and geohazard research. They may prove to be unmistakable stratigraphic markers for future basin analysis.
AB - The southern margin of the Scotia Sea hosts the convergent boundary between the Scotia and Antarctic plates where a number of small basins are situated. Mass transport deposits (MTDs) within two of these small basins, Dove and Scan basins, reveal the importance of seismicity, slope instabilities and depositional processes in their growth patterns. Swath-bathymetry and very high-resolution seismic data show that there are over 200 MTDs in these basins in the last 100 ky record. MTD characterizations are determined on the basis of their regional distribution, shape, apparent size and depth. Their sedimentary and tectonic implications are discussed, as well as the evidence of different triggering mechanisms in this region, which is characterized at present by moderate-to-high magnitude, shallow to intermediate earthquakes. MTDs are more abundant in the Dove Basin (with lenticular and wedge shapes), suggesting that this basin was affected by active tectonics to a greater degree than the Scan Basin. This finding is significant in the overall evolutionary context of the Scotia Sea region and Scotia-Antarctic plate geodynamics. Nevertheless, other factors -volcanic activity, vigorous bottom-currents, and/or higher sedimentation rates - must also be considered for the generation of MTDs in the Scan Basin, where a variety of processes generated more diverse MTD morphologies. Paleoseismological estimations of the repeated occurrence of wedge shaped MTDs in contact with fault scarps point to potential sources of large magnitude (Mw ~. 7.2-7.3) paleoearthquakes in several sites, in agreement with the present high magnitudes of regional seismicity. This study shows MTDs to be appropriate as paleoearthquake indicators in active tectonic settings. The distribution of MTDs in the southern Scotia Sea has important implications for geodynamic and geohazard research. They may prove to be unmistakable stratigraphic markers for future basin analysis.
KW - Antarctica
KW - Dove and Scan basins
KW - Mass transport deposits (MTDs)
KW - MTD triggering factors
KW - Paleoseismicity
KW - Slope instabilities
UR - http://www.scopus.com/inward/record.url?scp=84922979819&partnerID=8YFLogxK
U2 - 10.1016/j.gloplacha.2014.06.009
DO - 10.1016/j.gloplacha.2014.06.009
M3 - Article
AN - SCOPUS:84922979819
SN - 0921-8181
VL - 123
SP - 374
EP - 391
JO - Global and Planetary Change
JF - Global and Planetary Change
IS - Part B
ER -