High Resoluton Examination of the Intact "Microfossil" - Mineral Interface of ALH84001 for Evidence of Physical and Mineralogical Changes Consistent with Microbial Activity

该奖项在火星岩石特别研究机会活动 支持微生物活动的矿物学影响的调查， Dr. William W. Barker和Jillian F.地质系的班菲尔德， 威斯康星大学麦迪逊分校 该项目由联合国难民事务高级专员办事处供资。 极地计划，化学部和MPS办公室 多学科活动。 火星陨石ALH 84001 研究了地球化学的矿物学和结构学证据 硅酸盐矿物蚀变 本研究的具体目标是（1） 寻找低温和低温之间长期相互作用的证据， 含水流体和矿物表面的仔细检查 对于亚微观量的水合产物，例如粘土;以及 (2)来研究“纳米化石” 和下面的矿物作为聚合物介导的粘土形成的证据， 由于暴露于代谢副产物而导致的溶解特征，以及 化学特征，由于元素浓度与 生物聚合物的存在。 高分辨透射电子 高分辨透射电子显微镜（HRTEM）和能量过滤透射电子显微镜 将使用离子研磨和超微切片陨石样品的EFTEM 检查裂缝表面的矿物质， 低温蚀变 将收集更多信息 使用高分辨率扫描电子显微镜（HRSEM）和其他 现代显微镜技术能够分辨到原子水平。 这些方法将使检查的结构，组成， 在“微体化石”和 底层衬底。 如果ALH 84001含有生活在矿物附近的微生物， 表面，它们相互作用的精细尺度证据可能被保存在 微生物-矿物质界面 先进的物理和化学方法 将用于探测矿物表面的变化。 陆地 矿物-有机体相互作用模型将用于区分 生物学上从无机介导的改变作为一种手段， 评估早期火星生命的证据

This award in the Mars-Rock Special Research Opportunity activity supports investigation of mineralogical effects of microbial activity by Drs. William W. Barker and Jillian F. Banfield of the Geology Department, University of Wisconsin-Madison. The project is funded by the Office of Polar Programs, the Chemistry Division, and the MPS Office of Multidisciplinary Activities. Martian meteorite ALH84001 will be examined for mineralogical and textural evidence of biogeochemical silicate mineral alteration. The specific goals of the research are (1) to search for evidence of long-term interaction between low-temperature hydrous fluids and mineral surfaces by careful examination of surfaces for submicroscopic quantities of hydration products, such as clays; and (2) to examine the structure of the interface between the `nanofossils` and underlying minerals for evidence of polymer-mediated clay formation, dissolution features due to exposure to metabolic byproducts, and chemical signatures due to elemental concentrations associated with the presence of biopolymers. High resolution transmission electron microscopy (HRTEM) and energy-filtered transmission electron microscopy (EFTEM) of ion milled and ultramicrotomed meteorite samples will be used to examine the minerals at the crack surface for evidence of low-temperature alteration. Additional information will be gathered using high-resolution scaning electron microscopy (HRSEM) and other modern microscopy techniques capable of resolution to the atomic level. These methods will enable examination of the structure, composition, and mineralogy of the zone at the interface between the `microfossils` and underlying substrate. If ALH84001 contained microbes that lived in proximity to mineral surfaces, fine scale evidence for their interactions may be preserved at the microbe-mineral interface. Advanced physical and chemical methods will be used to detect alteration of the mineral surface. Terrestrial models for mineral-organism interaction will be used to distinguish biologically from inorganically-mediated alteration as a means of evaluating evidence of early Martian life.