Clinothems of the Cretaceous Berbice Canyon, offshore Guyana

Abstract

The Berbice Canyon of offshore Guyana evolved in the late Cretaceous in proximity to a margin that was separating from the African margin in response to the opening of the northern South Atlantic Ocean. The Berbice would be considered a shelf-incised canyon in the nomenclature of Harris and Whiteway, 2011. This study examines the nature of the canyon morphology, fill phases and fill architecture within the Berbice Canyon using ~7000 km2 of 3D seismic time and depth data, as well as chronostratigraphic data from Horseshoe-01 well drilled adjacent to the canyon fill. The Berbice displays composite canyon development with multiple phases of cut and fill. There are six primary incisional surfaces exhibiting a maximum width of 33km, a maximum relief of 1250 m and a composite maximum relief of 2650 m when decompaction is factored. The western side of the canyon system is primarily modified through destructional activities such as scalloping and side wall failures while the eastern side is primarily modified through constructional progradational activities. There are clinothems deposited within the canyon between incisional surfaces I3 and I4, primarily on the eastern side. The clinothems generally have a mounded shape and are primarily sourced from the southeast. The clinoforms —based on comparison to a dataset of clinoform morphometrics compiled by Patruno et al, 2015 — are shelf-margin / shelf-prism scale clinoforms.