Controls on the deposition and preservation of mixed fluvial and marginal marine successions
|6 December 2018
|17:00 - 18:00
|What is it:
|Department of Earth and Environmental Sciences
|Who is it for:
|University staff, Current University students
|Dr Michelle Shiers
This week's AAGP speaker is Dr Michelle Shiers from CASP.
Discerning the roles of autogenic and allogenic controls on the deposition,
accumulation and preservation of sedimentary successions requires characterisation
at a variety of scales. This is especially true for paralic environments where the
preserved stratigraphic record is complicated by spatial and temporal interactions of
fluvial, wave and tidal processes.
The Campanian Neslen Formation (Utah) represents a marine influenced fluvial succession
that accumulated in a humid, low-latitude coastal plain. Detailed lithofacies, architectural
element and sequence stratigraphic analyses of the succession was performed in order
to elucidate the relative balance of autogenic and allogenic processes. Outcrops in a range
of orientations relative to the palaeoshoreline, enable the geometries of complicated
architectural elements to be constrained. Study sites, average spacing 3 km, have been
used to produce a regional-scale correlation between sub-environments.
This study demonstrates a rare example of the transfer of the fluvial-to-marine transition
zone into the stratigraphic record. In contrast with previous studies that emphasise sea-level
change as the dominant control on paralic successions; this stratigraphic dataset demonstrates
the extent to which autogenic processes can modify the allogenic stratigraphic signature.
Dr Michelle Shiers
Role: Field Geologist
Biography: Michelle Shiers received her MGeol and PhD from the University of Leeds in 2012 and 2017. Her PhD, entitled ‘Controls on the deposition, accumulation and preservation of mixed fluvial and marginal-marine successions in coastal-plain settings’ focused on the multi-scale analysis of fluvial and shallow marine stratigraphy and sedimentology of the Neslen Formation, Utah. The research documented a rare example of a fluvial-to-marine transition zone in the stratigraphic record and emphasised the important interplay of autogenic and allogenic controls on paralic successions. The implications of this for the distribution of reservoir heterogeneities and their prediction in the subsurface were discussed. Michelle joined CASP in September 2017 as a field geologist and works as part of the Greater Caspian Provenance Project and Uralian Provenance Projects, incorporating heavy mineral analysis and petrography into her sedimentology skills.
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