Climate Change and Earth-Ocean-Atmosphere Systems.
Research: Carbonate Diagenesis
Diagenesis of modem biogenic carbonates can start while the parent organism that produced the carbonate is still alive and may persist for many millions of years! The increasing use of carbonates as proxies for reconstructing ancient conditions of precipitation requires that all diagenetic changes to have affected these proxies are accounted for. The change from unconsolidated lime sediment to hard limestone is often accompanied by the elimination of pore space with obvious consequences for the oil, gas and water industries. Fluids are the vehicle of diagenesis; their initial seawater composition changes as they are buried in sedimentary basins or on exhumation with the introduction of meteoric waters. Fluids are also introduced into sediments by human activities, such as mining, waste disposal sites, and during oil field production; these fluids often cause very rapid diagenetic changes.
Fabric development of calcite cement, their stereology and internal chemical variation through zoned cement sequences in limestones
Echinoderm Seawater Proxies
Exceptionally well-preserved echinoderm fossils provide evidence for fluctuations in the chemistry of seawater. First-order changes in Mg/Ca ratio indicated by echinoderms match other indicators of change but a detailed (~ 1 Ma) secular Mg/Ca profile for the Phanerozoic remains to be defined
Porosity evolution in Ordovician, Carboniferous and Cretaceous carbonate reservoirs from Texas, Kazakhstan and China