Paleobiology and Taphonomy of Exceptional Preserved Fossils from Jurassic Lacustrine Deposits, Beardmore Glacier Area and Southern Victoria Land, Antarctica

该奖项由极地方案办公室南极地质和地球物理方案提供，支持对南极洲横贯北极山脉的费拉群(侏罗纪)柯克帕特里克玄武岩(侏罗纪)、比尔德莫尔冰川地区和南部维多利亚陆地内湖泊互层中的生物群的古生物学和埋藏学(尸检史)的研究。柯克帕特里克玄武岩的沉积夹层代表了异常保存的不寻常的沉积物(或Konservat-Lagerstatten)，其特征是存在各种非生物矿化(或所谓的软体)生物。过去几十年的田野调查发现了丰富的甲壳类(具有非矿化外骨骼的双壳节肢动物)和鱼类的遗骸，不太常见的各种节肢动物的遗骸，如昆虫、合肢类和等足类，以及植物碎片。节肢动物和鱼类化石在保存质量上从脱节的碎片到关节的遗骸都可以与化石记录中已知的最好的化石相媲美。对湖泊沉积物的重新采集应该会产生更多保存完好的化石，可能包括更多的分类群，以及其他对古生态、墓葬和古环境解释重要的数据。目前的迹象表明，柯克帕特里克湖沉积为了解中生代高纬度淡水生态系统的演化史提供了重要的“窗口”。对柯克帕特里克湖沉积物的古生态和挖掘学研究有望提供额外的线索，了解过去地质历史中非矿化骨骼部分--可能还有软性部分--特殊保存的一般条件。这一点意义重大，因为我们目前对特殊保存条件的几乎所有理解都源于对海洋沉积物、边缘海洋沉积物或来自中低古纬度地区的淡水沉积物的研究。这项研究的主要目标是：1)收集和系统地记录南极比尔德莫尔冰川地区和维多利亚南部地区柯克帕特里克玄武岩遗址沉积夹层的生物群；2)记录和解释关于柯克帕特里克遗址的挖掘信息，包括化石的成岩蚀变；3)描述和解释与遗体化石有关的遗迹化石；以及4)记录和解释柯克帕特里克遗址特殊保存的地层和沉积学背景。可以想象的是，横跨北极山脉地区的侏罗纪遗址受到重视，因为从高古纬度地区的水生态系统中已知很少含有非生物矿化的化石。这项研究的完成将使人们对中生代高纬度湖泊生态系统的生物群和古生态有更全面的认识。柯克帕特里克遗址将为在全球范围内解释侏罗纪生物群提供有用的信息，因为它将提供更好的基础，以与保存异常完好的更知名的中低纬度沉积物进行比较。来自柯克帕特里克沉积物研究的数据有望提供关于为什么在淡水、高纬度环境中发生特殊生物保存这一根本问题的信息。

This award, provided by the Antarctic Geology and Geophysics Program of the Office of Polar Programs, supports a study of the paleobiology and taphonomy (postmortem history) of biotas from lacustrine interbeds within the Kirkpatrick Basalt of the Ferrar Group (Jurassic), Beardmore Glacier area and southern Victoria Land, Transantarctic Mountains, Antarctica. Sedimentary interbeds of the Kirkpatrick Basalt represent unusual deposits of exceptional preservation (or Konservat-Lagerstatten), characterized by the presence of a variety of non-biomineralizing (or so-called soft-bodied) organisms. Fieldwork in previous decades resulted in 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, as well as plant fragments. The arthropod and fish fossils range in preservational quality from disarticulated pieces to articulated remains comparable to the finest known from the fossil record. Renewed collecting of the lacustrine deposits should yield additional exceptionally preserved fossils, possibly including additional taxa, and other data important for paleoecologic, taphonomic, and paleoenvironmental interpretation. 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 the Kirkpatrick lake 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. Principal objectives of the research are: 1) to collect and systematically document the biota of the sedimentary interbeds of the Kirkpatrick Basalt sites in the Beardmore Glacier area and southern Victoria Land, Antarctica; 2) to document and interpret taphonomic information on the Kirkpatrick sites, including diagenetic alteration of fossils; 3) to describe and interpret trace fossils that are associated with the body fossils; and 4) to document and interpret the stratigraphic and sedimentologic context of exceptional preservation in the Kirkpatrick sites.Considerable importance attaches to the Jurassic sites in the Transantarctic Mountains area 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 lacustrine ecosystems of the middle Mesozoic. The Kirkpatrick sites will provide information useful for interpreting Jurassic biotas in a global context, as it will provide an improved basis for comparison with better-known, low- to middle-latitude deposits of exceptional preservation. Data from study of the Kirkpatrick deposits are expected to provide information concerning the fundamental question of why exceptional preservation of organisms has occurred in freshwater, high latitude settings.