Monday, 2 December 2013 Back to News

The Stratigraphic Record Of Carbonate Platforms and Ramps II

BGS staff are set to present their research at the American Geophysical Union (AGU) Fall meeting between 9th and 13th December 2013 in San Francisco.

Heather Stewart will co-present a poster session entitled 'Storm Generated Bedforms and Relict Dissolution Pits And Channels On The Yucatan Carbonate Platform'. She will discuss, with her colleagues, a geophysical and geotechnical hazard site survey undertaken aboard the R/V Justo Sierra in April 2013.

Conducted within the Chicxulub impact crater, 32 kilometres northwest of Progreso in Mexico, the study used multibeam bathymetry coverage to discover that the Yucatan Shelf consists of flat-lying, hard limestone rock overlain by isolated ribbons of carbonate sand.

While the geological origins of the features found will require further investigation, the study’s observations show that the dominant modern sediment formation and transport processes on this starved platform are from large storms and hurricanes that place large regions of the platform at wave base.

Heather will also give an oral presentation on Wednesday 11th December in the session Carol Cotterill is convening, ‘Climate Change and Cryospheric Systems IV.’ She will present with Tom Bradwell on how “Shallow seafloor glacial features reveal ice streaming and ice-sheet re-advance in the last British Ice Sheet, Offshore Eastern Scotland and North-Eastern England”.

The study combined echosounder datasets, high-resolution digital surface models, 2D Seismic reflection profiles and shallow cores to reveal strong evidence for onshore-offshore paleo-ice streaming in eastern Scotland and northeastern England. Its most notable discovery was that an extensive advance of paleo-ice streams took place in the North Sea Basin during overall ice-sheet retreat.

Margaret Stewart also has poster in the same session, entitled 'A History of De-glaciation In The Central North Sea: Seabed Incisions in Bathymetric and Seismic Data'. She will present on recently acquired high-resolution bathymetric surveys that have been used to identify more than 35 seabed incisions from the area between 56°N 2°E and 59°N and 1°W.

Channelized linear depressions have been known on the seabed of the central North Sea for over a hundred years, but this study has provided new insights into nature of their formation and their relationship to the de-glaciation of the central North Sea after the last glacial maximum.

Finally, Carol Cotterill will have a poster in her ‘Climate Change and Cryospehric Systems’ session, entitled 'Episodic glacially Derived Thrusts: A Case Study From the Central North Sea Basin'. Based on an extensive survey of 2D seismic in the central North Sea, this study revealed a series of thrusts within glacial sediments on the western flank of the Dogger Bank. It endeavored to map these thrust features, and to work out the direction of movements and the processes causing these thrusts. Stewart concludes that although the thrusts extend upwards to near seabed level, there is no apparent seabed morphological expression, suggesting that any expected topographical evidence has been eroded by later glacial or periglacial erosion.

The BGS are excited to join more than 22,000 Earth and space scientists, educators, students, and other leaders in San Francisco, as they gather to present ground-breaking research and connect with colleagues. Look out for updates from the conference as it happens!