The mixed-bed glacial landform imprint of the North Sea Lobe in the western North Sea     

David H. Roberts  Elena Grimoldi  Louise Callard  David J.A. Evans  Chris D. Clark  Heather A. Stewart  Dayton Dove  Margot Saher  Colm Ó Cofaigh  Richard C. Chiverrell  Mark D. Bateman  Steven G. Moreton  Tom Bradwell  Derek Fabel  Alicia Medialdea 《地球表面变化过程与地形》2019,44(6):1233-1258

During the last glacial cycle an intriguing feature of the British-Irish Ice Sheet was the North Sea Lobe (NSL); fed from the Firth of Forth and which flowed south and parallel to the English east coast. The controls on the formation and behaviour of the NSL have long been debated, but in the southern North Sea recent work suggests the NSL formed a dynamic, oscillating terrestrial margin operating over a deforming bed. Further north, however, little is known of the behaviour of the NSL or under what conditions it operated. This paper analyses new acoustic, sedimentary and geomorphic data in order to evaluate the glacial landsystem imprint and deglacial history of the NSL offshore from NE England. Subglacial tills (AF2/3) form a discontinuous mosaic interspersed with bedrock outcrops across the seafloor, with the partial excavation and advection of subglacial sediment during both advance and retreat producing mega-scale glacial lineations and grounding zone wedges. The resultant ‘mixed-bed’ glacial landsystem is the product of a dynamic switch from a terrestrial piedmont-lobe margin with a net surplus of sediment to a partially erosive, quasi-stable, marine-terminating, ice stream lobe as the NSL withdrew northwards. Glaciomarine sediments (AF4) drape the underlying subglacial mixed-bed imprint and point to a switch to tidewater conditions between 19.9 and 16.5 ka cal BP as the North Sea became inundated. The dominant controls on NSL recession during this period were changing ice flux through the Firth of Forth ice stream onset zone and water depths at the grounding line; the development of the mixed-bed landsystem being a response to grounding line instability. © 2018 John Wiley & Sons, Ltd.  相似文献   

Contribution to knowledge regarding the sources of earthquakes on the island of Ischia (Southern Italy)     

Cubellis  Elena  Luongo  Giuseppe  Obrizzo  Francesco  Sepe  Vincenzo  Tammaro  Umberto 《Natural Hazards》2020,100(3):955-994

Natural Hazards - This paper analyses data regarding the seismicity and ground deformations of the island of Ischia. The goal is to describe these phenomena as a space–time process, exploring...  相似文献   

Geology of the Murcia Valley and Flood Plain Modifications in the Construction of the Circus Maximus,Rome, Italy     

Elena Carpentieri  Donatella de Rita  Giuseppe Della Monica 《Geoarchaeology》2015,30(6):483-494

This paper presents a morphological and hydrogeological reconstruction of the Murcia Valley at the location of the great Roman stadium Circus Maximus in Rome. We reconstruct a valley segment using ERT (electrical resistivity tomography) and geoarchaeological drilling data that identified three main layers. The basal layer, with high resistivity values and convex shapes, is correlated to alluvial gravel and lithified silt‐clay sediments. The middle layer shows low‐to‐medium resistivity values extending to concavities between the basal convex shapes. The very low resistivity values of this middle layer characterize elliptical to circular morphologies and have been ascribed to the presence of water‐saturated clay‐silt and peaty sediments. The surface layer is characterized by widespread lateral inhomogeneity interpreted as anthropogenic fill. The data indicate a pre‐Roman anastomosed alluvial plain subsequently modified by human intervention. In an effort to reclaim the valley for construction of the Circus, the Romans utilized the natural topography and created a central embankment, later becoming the Spina, by filling depressions with sand taken from adjacent bars. Our study contributes to (1) knowledge of the pre‐Roman landscape, (2) understanding anthropogenic modification of the Murcia Valley flood plain, and (3) archaeological interpretation of the monument.  相似文献