WEBINAR SERIES ON GEOSCIENCE FOR SUSTAINABLE DEVELOPMENT (EPISODE NO 10)
Date: October 11 (Sunday), 2020
Time: 20:00 NPT (+5:45 GMT)
Welcome to the 10th episode of the Webinar series on GeoScience for Sustainable Development: " Active Faulting and Subsurface Structural Variability of the Himalayan Foreland Basin, Nepal (October 11, 2020, 20:00 NPT (+5:45 GMT))
Registration Link: https://tinyurl.com/yy8vlg3o
Presenter: Prof. Dr. John W.F. Waldron, Department of Earth & Atmospheric Science, University of Alberta, Canada
Moderator: Asst. Prof. Dr. Basanta Raj Adhikari
Abstract
The Himalayan Orogen is the Earth’s largest and most active site of continent-continent collision. Like many orogens, it has an extensive foreland basin system, lying to the south of the Main Frontal Thrust. Portions of the the foreland basin have been incorporated into the orogen by faulting and folding at the thrust front, forming the Sub-Himalaya,. The foreland basin system has been formed as a result of flexure of the Indian Plate under the advancing load of the orogen. Foreland basin stratigraphy can therfore be used to investigate the behaviour of basement features during continent-continent collision, and to test links between basement structure, along-strike segmentation of deformation, and lithospheric flexure. The Himalayan orogen has been segmented along its strike at the scale of hundreds of kilometres. Heterogeneities in the Indian plate, such as crustal scale basement faults and ridges, are possible controls on this lateral segmentation. Understanding the mechanisms of this longitudinal variability could further our understanding of the orogen, and potentially improve hazard assessment. Using 2D seismic reflection data, we mapped several regional horizons to characterize the geometry of the Ganga Basin, Nepal. Our findings suggest that basement features have been inherited by the Himalayan foreland basin, controlling accommodation. These basement features likely play a key role in the spatial localization of active deformation and may influence seismicity patterns varying along the strike of the orogen. We also identified strike-slip faults extending south of the Main Frontal Thrust, linked to a newly identified Outer Frontal Thrust that has developed since 500 ka. This demonstrates that Himalayan ruptures may pass under the present-day trace of the Main Frontal Thrust as blind faults that extend tens of kilometres into the foreland basin.
John W.F. Waldron Biography
John Waldron grew up in the UK, mainly in the Essex suburbs of London. As a teenager he developed an interest in paleontology, collecting fossils in classic areas of British geology. Attending Cambridge University from 1974, he was subverted from paleontology into studies of mountain belts by the glamour of the new plate tectonics. From 1977 to 1981 he worked as a PhD student at Edinburgh University, on the geology of SW Turkey. In January 1981, he came to Memorial University of Newfoundland, Canada, where he briefly held a post-doctoral research fellowship. From 1981 until 2000 he worked at Saint Mary’s University Nova Scotia. Working on sedimentation and tectonics in eastern Canadian basins. In 2000 he moved to the University of Alberta, where has taught introductory Earth science, tectonics and structural and field geology. He developed an outdoor teaching installation, the Geoscience Garden, at the University of Alberta, consisting of over 80 large boulders installed outdoors in a geologically meaningful arrangement in an outdoor environment. His research deals with deformed sedimentary rocks from both sedimentary and structural geological perspectives, particularly in Atlantic Canada. With Glen Stockmal of the Geological Survey of Canada he identified a triangle zone at the Acadian thrust front of the Newfoundland Appalachians which resulted in an upsurge of exploration and the drilling of new wells during the 1990s. He received the Gesner medal of the Atlantic Geoscience Society in 2009. His work is characterised by (a) innovative integration of geophysical data with outcrop stratigraphic sections and structures in frontier areas that lack well ties to stratigraphy, and (b) a continuous awareness of the interplay between sedimentation and tectonics, and the recognition that structures like soft-sediment folds, salt expulsion minibasins, and mélanges, are formed by a combination of “sedimentary” and “tectonic” processes that are often intergradational. He has applied his expertise, developed in the basins of eastern Canada, to studies of sedimentation and tectonics in older rocks of the Appalachians, in the Archean of the Slave Craton, in the Cordillera of northern British Columbia, and most recently in the foothills and foreland basin of the Nepal Himalaya.
How to register:
Registration Link: https://tinyurl.com/yy8vlg3o
Date: October 11 (Sunday), 2020
Time: 20:00 NPT (+5:45 GMT)