The Offshore Aquifer System of Nantucket Island
ACRONYM
OASIS
Title
The Offshore Aquifer System of Nantucket Island
General information
Offshore freshened groundwater (OFG) is a global phenomenon, but OFG-systems that have been identified to date are essentially a by-product of other investigations, i.e. scientific drilling with other geological or resource-related objectives. As a result, the origin, evolution and distribution of the less saline water still remains hypothetical for most OFGs. In summer 2025, an IODP project solely dedicated to exploring OFG will be carried out for the first time. IODP 501 will take place off the coast of New England (Massachusetts, USA) from May to August, and will provide a unique opportunity to study the subseafloor hydrogeology. The planned drilling and sampling will show whether a groundwater system actually exists beneath the seafloor and whether it can be described using the classical understanding of aquifers and confining layers as known from land. Pumping tests will be of particular importance by providing essential information on subsurface physical properties. Moreover, they can be used to test if there is an active connection between the onshore and offshore systems. They also allow larger volumes of water to be sampled for age dating. The proposed project will make use of the newly gained data on IODP Leg 501 by applying numerical models in order to identify key factors and processes influencing groundwater salinisation in the continental shelf groundwater system. The study will also contribute to a better understanding of the timescales and dynamics of the continental shelf groundwater system by modelling transport and reaction processes using various hydrogeochemical tracers beyond salinity. The results of this study are expected to improve our understanding of the New England offshore groundwater system in general and provide broader insights into the formation and evolution of OFG under changing climate and sea level conditions worldwide.
Start
November, 2025
End
October, 2027
Funding (total)
-
Funding (GEOMAR)
241000
Funding body / Programme
-
DFG
/ Infrastructure Priority Programmes
Coordination
Helmholtz-Zentrum für Ozeanforschung Kiel (GEOMAR), Germany
Contact
