Paleoenvironment, which encompasses paleoclimate and paleogeology, is a focus area for several faculty and students in the BPSoG. Beyond the historic record of the past few centuries, our only knowledge of the earth’s climate and geography comes from proxy records. The pre-historic data are valuable for several reasons: they significantly extend the baseline of information; they enable an understanding of the full range of variation; and they carry the record beyond the influence of anthropogenic change.
Such chronologies are typically extracted from dated sediment cores from oceans and lakes, and in some cases from ice cores and tree rings. We analyze downcore records of sedimentologic and geochemical factors that represent a chronology of paleoenvironmental change. Factors of interest include changes in: paleo-temperature, salinity, sea level, vegetation type, redox conditions, and the frequency of geohazard events such as major storms, tsunamis and earthquakes.
The resulting paleoenvironmental data can be used to better interpret geologic history, and also to inform models for predicting future environmental conditions. Projecting climate change and the risk of geohazards has both scientific and practical value. Numerical models based on reliable high-resolution records of geologic change enable society to better deal with the need for mitigation of climate pertubations, and to more accurately assess the true long-term risk of geohazards.
Faculty and students are also involved in the study of ancient environments in the rock record over a wide range of geologic time intervals. Our analytical methods include sedimentological examination of outcrops and subsurfaces cores, oxygen isotope signatures derived from fossils and carbonate minerals, bulk- and compound-class elemental and isotopic proxies, temperature biomarkers, and modeling of geochemical cycles.
Some examples of departmental research on paleoenvironment include:
• Investigating the effects of climate and tectonics on the initiation and demise of mega palaeo-lakes in the middle Kalahari Desert of northern Botswana
• Investigating the use of nitrogen isotopes as a water column paleo-redox proxy in sedimentary systems.
• Analysis of nitrogen and carbon cycling and paleo-redox conditions through mass extinction events such as the Cretaceous-Paleogene and end-Triassic events.
• Analysis of depositional water column paleo-redox conditions and biogeochemistry through glacial-interglacial cycles in the Black Sea.
• Early diagenesis in modern marine sediments and its impact on primary signals
• Metal cycling and its implication for the (ultra-) deep biosphere
• Investigation and application of paleoproxies with emphasize on trace metals
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