Depth to Quaternary regional unconformities offshore of the Delmarva Peninsula, including Maryland and Virginia state waters
Dates
Publication Date
2023-05-19
Start Date
1974-05-15
End Date
2015-07-14
Citation
Foster, D.S., Brothers, L.L., Baldwin, W.E., and Pendleton, E.A., 2023, Geospatial data layers of shallow geology from the inner continental shelf of the Delmarva Peninsula, including Maryland and Virginia state waters: U.S. Geological Survey data release, https://doi.org/10.5066/P9GQY0ZN.
Summary
Geologic structure and isopach maps were constructed by interpreting over 19,890 trackline kilometers of co-located multichannel boomer, sparker and chirp seismic reflection profiles from the continental shelf of the Delmarva Peninsula, including Maryland and Virginia state waters. In this region, Brothers and others (2020) interpret 12 seismic units and 11 regional unconformities. They interpret the infilled channels as Late Tertiary and Quaternary courses of the Susquehanna, Potomac, Rappahannock, York and James Rivers and tributaries, in addition to a broad drainage system. These regional unconformities form a composite unconformity interpreted as the Quaternary-Tertiary (Q-T) unconformity. A depth to Tertiary (Uqt) and total Quaternary [...]
Summary
Geologic structure and isopach maps were constructed by interpreting over 19,890 trackline kilometers of co-located multichannel boomer, sparker and chirp seismic reflection profiles from the continental shelf of the Delmarva Peninsula, including Maryland and Virginia state waters. In this region, Brothers and others (2020) interpret 12 seismic units and 11 regional unconformities. They interpret the infilled channels as Late Tertiary and Quaternary courses of the Susquehanna, Potomac, Rappahannock, York and James Rivers and tributaries, in addition to a broad drainage system. These regional unconformities form a composite unconformity interpreted as the Quaternary-Tertiary (Q-T) unconformity. A depth to Tertiary (Uqt) and total Quaternary sediment thickness (Q) isopach are included with this data release. Other products in this data release include thickness of an early Pleistocene unit (Qbd), thickness of a Pleistocene highstand system tract (Q2), thickness of a post last glacial maximum (LGM) fluvial/estuarine unit (Qcch), thickness of Holocene to modern marine sediment (Qmn), depth to the base of the Persimmons Point and Ocean City paleochannels (U4), depth to the base of the Exmore and Belle Haven paleochannels (U6), depth to the base of the Eastville paleochannel and tributaries (U8), depth to the base (fluvial unconformity) of the Cape Charles paleochannel and tributary paleochannels (fluvial unconformity, U10) and the base (tidal ravinement) of associated Holocene tidal and back-barrier deposits (tidal ravinement surface, U10.5).
This dataset contains six grids representing depth to regional unconformities that separate seismic stratigraphic units offshore of the Delmarva Peninsula, including Maryland and Virginia state waters (Brothers and others, 2020). Fluvial downcutting and marine transgressions during the Quaternary have shaped the Tertiary surface and geologic framework of the region. Grids include: 1) Uqt, the Quaternary-Tertiary composite unconformity; 2) U4, the subaerially and fluvially eroded lower boundary of the Persimmons Point and Ocean City Paleochannels; 3) U6, the subaerially and fluvially eroded lower boundary of the Exmore (Qx) and Belle Haven Paleochannels; 4) U8, the subaerially and fluvially eroded lower boundary of the Eastville Paleochannel and tributaries (Qe);5) U9, the transgressive ravinement surface above Qe and at the base of a Pleistocene highstand system tract (Q2); and 6) U10-U10.5, the composite of subaerially eroded (U10) and tidal ravinement (U10.5) unconformities that are the lower boundaries of the Cape Charles Paleochannel and tributaries and tidal inlet and back-barrier estuarine deposits.
Preview Image
Browse graphic of depth to the Quaternary-Tertiary composite unconformity