Research Objectives:
Sedimentary interbeds of the Kirkpatrick Basalt represent unusual, exceptionally well preserved deposits, characterized by the presence of a variety of non-biomineralizing (so-called soft-bodied) organisms. Fieldwork in previous decades resulted in the discovery of abundant remains of conchostracans (bivalved arthropods having non-mineralized exoskeletons) and fishes; less common remains of various arthropods such as insects, syncarids, and isopods; and plant fragments. The arthropod and fish fossils range in preservational quality from disarticulated pieces to articulated remains comparable to the finest in the fossil record.
Present indications are that the Kirkpatrick lake deposits offer important windows into the evolutionary history of high-latitude, freshwater ecosystems of the middle Mesozoic. Paleoecologic and taphonomic study of these deposits can be expected to provide additional clues to the general conditions under which exceptional preservation of non-mineralized skeletal parts, and perhaps soft parts, occurred in the geologic past. This is significant because nearly all of our current understanding of conditions surrounding exceptional preservation has been derived from studies of marine deposits, marginal-marine deposits, or freshwater deposits from low to middle paleolatitudes.
Our principal objectives are to
+ Collect and systematically document the biota of the sedimentary interbeds of the Kirkpatrick sites in the Beardmore Glacier area and southern Victoria Land;
+ Document and interpret taphonomic information on the Kirkpatrick sites, including diagenetic alteration of fossils;
+ Describe and interpret trace fossils that are associated with the body fossils; and
+ Document and interpret the stratigraphic and sedimentologic context of exceptional preservation.
Considerable importance attaches to the Jurassic sites in the Transantarctic Mountains, because few sites from aqueous ecosystems of high-paleolatitude areas are known to contain non-biomineralized fossils. Completion of this study will result in a more complete understanding of the biota and paleoecology of high-latitude lake ecosystems of the middle Mesozoic. The Kirkpatrick sites will also provide information useful for interpreting Jurassic biotas in a global context. Data from this study are expected to provide information on the fundamental question of why exceptional preservation of organisms has occurred in freshwater, high high-latitude settings.
