Evidence for widespread creep on the flanks of the Sea of Marmara transform basin from marine geophysical data
D.J. Shillington et al., Lamont-Doherty Earth Observatory, Columbia University, Palisades, New York 10964, USA. Posted online 19 Mar. 2012; doi: 10.1130/G32652.1.
New data indicate that "waves" in the sediments in the Sea of Marmara formed by slow-motion landsliding, wherein sediments slowly creep downhill over hundreds of thousands of years, creating wrinkles in the sedimentary layers. The Sea of Marmara straddles the North Anatolian Fault, an active strike-slip fault in northern Turkey that poses a serious seismic hazard to Istanbul. Researchers D.J. Shillington of the Lamont-Doherty Earth Observatory and colleagues note that it is important to understand the sedimentary features here because they host a record of past motions on the North Anatolian fault and other faults in the area. In this case, they report, movement on the faults shapes the topography of the seafloor, creating the slopes necessary for the sediments to creep downhill. As a result, the wrinkles formed by creep might be a clue to past fault activity. The gradual downhill movement of sediments by creeping may also reduce the potential for catastrophic landslides triggered by earthquakes.
Timing of Iapetus Ocean rifting from Ar geochronology of pseudotachylytes in the St. Lawrence rift system of southern Quebec
Tim M. O'Brien and Ben A. van der Pluijm, Dept. of Earth and Environmental Sciences, University of Michigan, 1100 North University Ave., Ann Arbor, Michigan 48109, USA. Posted online 19 Mar. 2012; doi: 10.1130/G32691.1.
|Contact: Christa Stratton|
Geological Society of America