Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
8914564 | Proceedings of the Geologists' Association | 2018 | 16 Pages |
Abstract
Proglacial Lake Humber formed in the Vale of York and Ancholme Valley during the Late Devensian (Weichselian) glaciation, but its lake levels and their precise ages are uncertain. Three-dimensional geological modelling, based on 193 borehole sediment logs from the eastern part of the Vale of York, indicates that glaciolacustrine sediments extend no higher than 10â¯m O.D. By contrast, recent palaeoenvironmental reconstructions for the region that suggest Lake Humber had eight recessional shorelines, extending from 42â¯m to 5â¯m O.D. Above 10â¯m O.D., the sediments become more discontinuous, and comprise clay with occasional chalk and flint gravel, and matrix-rich diamicton interdigitated with sands and gravels. Sedimentary and geochemical analyses of sands and gravels from one of the putative shorelines, at 25â¯m O.D., indicate an easterly provenance for these sediments. They are interpreted here as colluvial deposits, sourced largely by periglacial weathering of Jurassic and chalk bedrock. Collectively, the geological evidence suggests that the highest level of Lake Humber during the Late Devensian did not exceed 10â¯m O.D., and therefore reconstructions invoking higher lake levels are thought to be unlikely.
Related Topics
Physical Sciences and Engineering
Earth and Planetary Sciences
Geology
Authors
Della K. Murton,