Collaborative Research: Antiquity of Life in Salt Deposits? A Rb-Sr Age-Dating Study

Riciputi0418651这个项目试图验证微生物可以在充满卤水的岩盐晶体包裹体中存活长达10^8年的地质证据。这项研究的目标是获得两个以前培养过微生物的古代盐岩中卤水包裹体的绝对辐射年龄：来自新墨西哥州二叠纪萨拉多组的晶体和来自巴西白垩纪Muribeca蒸发岩的“Chevrons”。这样的年代测定将消除人们对流体包裹体年龄的怀疑，所谓的二叠纪和白垩纪微生物就是从这些包裹体中提取出来的。获得盐岩中卤水包裹体的绝对年龄对于细菌在地球上的长期生存和天体生物学具有深远的意义，并可能为未来探索火星和太阳系其他地区的生命贡献技术。据称，世界上最古老的生物是芽胞形成细菌Virgibacillussp。二叠系菌株2-9-3是从250 Ma二叠系萨拉多组盐岩胶结物中的卤水包裹体中培养出来的。对这些样品中的单个卤水包裹体进行Rb-sr测年将明确地确定Virgibacillussp.在萨拉多盐类沉积时，2-9-3被捕获在流体包裹体中。从白垩纪穆里贝卡组原生人字形岩盐中的卤水包裹体中培养出古生菌。用Rb-sr法测定这些白垩纪盐岩中的卤水包裹体的年龄将确定产生新发现的嗜盐古细菌的卤水包裹体的年龄是否为100 Ma。从这笔赠款中获得的信息以在国家会议上的陈述和期刊文章的形式向研究界传播。在每年为宾厄姆顿大学的研究生和本科生开设的地球生物学研讨会上，以及在德克萨斯大学共同教授的分析地球化学课上，都展示了这一结果。首席调查员参加了一项针对K-12学生的暑期充实计划，对环境中的微生物进行实地和实验室研究，包括显微镜和环境扫描电子显微镜观察各种样品，包括盐类中的卤水包裹体。一个关于卤水包裹体中微生物生命和保存的网站介绍了该项目的最新研究。(与Lowenstein/0418758/SUNY Binghamton合作研究)

Riciputi0418651This project seeks to verify geological evidence that microorganisms can survive inside the brine-filled inclusions of halite crystals for periods of 10^8 years. The goal of the research is to obtain absolute radiometric ages of brine inclusions from two ancient halites from which microorganisms have been previously cultured: crystals from the Permian Salado Formation, New Mexico and "chevrons" from the Cretaceous Muribeca evaporites of Brazil. Such dating will remove doubts about the ages of the fluid inclusions from which the purported Permian and Cretaceous microorganisms were extracted. Obtaining absolute ages of brine inclusions in halite has profound implications for long-term bacterial survival on Earth and for astrobiology, and may contribute techniques to future exploration for life on Mars and other parts of the solar system.The purported world's oldest living organism, the spore-forming bacterium Virgibacillus sp. Permian strain 2-9-3, was cultured from a brine inclusion in halite cement of the 250 Ma Permian Salado Formation. Rb-Sr dating of individual brine inclusions from these samples will establish unequivocally whether Virgibacillus sp. 2-9-3 was trapped in a fluid inclusion at the time of deposition of the Salado salts. Archaeal strains have been cultured from brine inclusions from primary chevron halite of the Cretaceous Muribeca Formation. Dating brine inclusions in these Cretaceous halites by Rb-Sr methods will ascertain with certainty whether the brine inclusions that yielded the newly discovered halophilic Archaea are 100 Ma in age.The information obtained from this grant is disseminated to the research community as presentations at national meetings and as journal articles. The results are illustrated in a geobiology seminar offered each year to graduate/undergraduate students at Binghamton, and in an analytical geochemistry course co-taught at UT. The Principal Investigator participates in a summer enrichment program for K-12 students with field and laboratory work on microorganisms in the environment, including microscope and Environmental Scanning Electron Microscope viewing of an assortment of samples including brine inclusions in salt. A website on microbial life and preservation in brine inclusions features current research from this project.(Collaborative research with Lowenstein/0418758/SUNY Binghamton)