The majority of New Providence Island, Bahamas, formed during the last interglacial sea-level highstand (MIS 5e) at 129-116 kybp during which sea level oscillated 10-15 m. This oscillation divided deposition into early and late substages (Fig. 1) (Reid, 2010). In addition to the two MIS 5e substages, smaller scale sea-level oscillations produced extensive lateral accretion of beach ridges and associated subtidal deposits. These downstepping ridges are an excellent record of the sea-level oscillations in the Bahamas. To decipher the facies geometries of the downstepping beach ridges and their associated facies, we collected approximately 33 km of high-resolution GPR and GPS data from September 9-12, 2014. An extensive network of 2D GPR profiles was recorded on roads and bush trails to capture 3D geometries, thickness, and facies correlations. Thisnew near surface geophysical data set will be used help correlate and expand insights gained from local outcrops and boreholes to the regional scale. The data processing and interpretation is not yet completed. Here we report preliminary findings obtained after a first look at some of the data.
First Results from a Regional GPR Survey of Downstepping Pleistocene (MIS 5E) Beach Deposits: New Providence, Bahamas
ERCOLI, MAURIZIO;
2014
Abstract
The majority of New Providence Island, Bahamas, formed during the last interglacial sea-level highstand (MIS 5e) at 129-116 kybp during which sea level oscillated 10-15 m. This oscillation divided deposition into early and late substages (Fig. 1) (Reid, 2010). In addition to the two MIS 5e substages, smaller scale sea-level oscillations produced extensive lateral accretion of beach ridges and associated subtidal deposits. These downstepping ridges are an excellent record of the sea-level oscillations in the Bahamas. To decipher the facies geometries of the downstepping beach ridges and their associated facies, we collected approximately 33 km of high-resolution GPR and GPS data from September 9-12, 2014. An extensive network of 2D GPR profiles was recorded on roads and bush trails to capture 3D geometries, thickness, and facies correlations. Thisnew near surface geophysical data set will be used help correlate and expand insights gained from local outcrops and boreholes to the regional scale. The data processing and interpretation is not yet completed. Here we report preliminary findings obtained after a first look at some of the data.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
