2 research outputs found
Voyage Report RV Tangaroa Voyage TAN1703, 5 April – 1 May 2017
Meteoric recharge and topographically-driven flow are the most important sources of
groundwater recharge in terrestrial settings. In passive continental margins, topographically driven meteoric (TDM) groundwater is only one of a range of drivers of offshore groundwater
flow. Other drivers include seawater recirculation, sediment loading, geothermal convection,
and diagenesis. Sea level has been much lower than today for 80% of the Quaternary, resulting
in the emergence of extensive sections of continental shelf, a reduction of pressure exerted by
the sea water column, as well as steepening of the hydraulic gradient and an increase in
hydraulic head. The potential of TDM recharge to establish extensive water tables, create
massive groundwater fluxes, and generate pore overpressures and discharges across the
continental shelf and upper continental slope must have been significantly higher during the
majority of the last 2.6 Ma than it is today. Considering that geothermal convection is strongest
beneath the continental slope and tends to be dominated by TDM flow during sea level
lowstands, whereas sediment loading is most important during rapid deglaciations in high
sedimentation zones, TDM recharge is a likely very important driver of offshore groundwater
systems in continental shelves and upper slopes globally.peer-reviewe
Voyage report RV Tangaroa voyage TAN1703, 5 April-1 May 2017
Meteoric recharge and topographically-driven flow are the most important sources of
groundwater recharge in terrestrial settings. In passive continental margins, topographically driven meteoric (TDM) groundwater is only one of a range of drivers of offshore groundwater
flow. Other drivers include seawater recirculation, sediment loading, geothermal convection,
and diagenesis. Sea level has been much lower than today for 80% of the Quaternary, resulting
in the emergence of extensive sections of continental shelf, a reduction of pressure exerted by
the sea water column, as well as steepening of the hydraulic gradient and an increase in
hydraulic head. The potential of TDM recharge to establish extensive water tables, create
massive groundwater fluxes, and generate pore overpressures and discharges across the
continental shelf and upper continental slope must have been significantly higher during the
majority of the last 2.6 Ma than it is today. Considering that geothermal convection is strongest
beneath the continental slope and tends to be dominated by TDM flow during sea level
lowstands, whereas sediment loading is most important during rapid deglaciations in high
sedimentation zones, TDM recharge is a likely very important driver of offshore groundwater
systems in continental shelves and upper slopes globally.peer-reviewe