Title: Reconciling exhumation models and sediment volumes in passive margin basins
Researchers: Dr Chris Mark and Dr David Chew
1. Project Background and Rationale A dynamic mantle control on the spatial pattern of uplift and exhumation observed across the British Isles has been proposed for both the Late Jurassic (e.g., Jones et al., 2012; Underhill and Partington, 1993) and Paleocene (see Fig. 1; e.g., Cogné et al., 2016; Jones et al., 2001; White and Lovell, 1997). This has implications for: (1) timing, flux, and nature of sediment supply to adjacent basins, which will impact hydrocarbon reservoir location and quality; and (2) the spatial and temporal distribution of exhumation, which will control the exposure level (depth) and timing of onshore units hosting minerals of economic value.
2. Hypotheses Transient, dynamically-supported uplift should result in increased exhumation and drainage divide reorganisation (e.g., Braun, 2010), as should the isostatic response to possible crustal underplating associated with the Paleogene event (Tomlinson et al., 2006). Enhanced exhumation is expected to occur as surface uplift increases surface slopes, leading to increased stream power; differential uplift can occur either with respect to the geometry of the upwelling mantle, or because uplift is partitioned onto pre-existing structural weaknesses (e.g., Burov and Cloetingh, 2009).
3. Objectives • Determining the provenance of Jurassic–Palaeogene reservoir sandstones by multi-method geo- and thermochronology on zircon, apatite • Reconciling the exhumation record of the Irish onshore with the delivery of sediment to the Atlantic conjugate passive margins • Integrating geochronology with phase-mapping by SEM-MLA to obtain multiple provenance information from single clasts (e.g. in very coarse-to-pebbly sandstones)