Large and Robust Lenticular Microorganisms on the Young Earth ⇑ ⇑ Dorothy Z
Precambrian Research 296 (2017) 112–119 Contents lists available at ScienceDirect Precambrian Research journal homepage: www.elsevier.com/locate/precamres Large and robust lenticular microorganisms on the young Earth ⇑ ⇑ Dorothy Z. Oehler a, , Maud M. Walsh b, Kenichiro Sugitani c, Ming-Chang Liu d, Christopher H. House e, a Planetary Science Institute, Tucson, AZ 85719, USA b School of Plant, Environmental and Soil Sciences, Louisiana State University, Baton Rouge, LA 70803-2110, USA c Graduate School of Environmental Studies, Nagoya University, Nagoya, Japan d Department of Earth, Planetary, and Space Sciences, University of California at Los Angeles, Los Angeles, CA 90095-1567, USA e Department of Geosciences, The Pennsylvania State University, University Park, PA 16802, USA article info abstract Article history: In recent years, remarkable organic microfossils have been reported from Archean deposits in the Pilbara Received 18 November 2016 craton of Australia. The structures are set apart from other ancient microfossils by their complex lentic- Revised 29 March 2017 ular morphology combined with their large size and robust, unusually thick walls. Potentially similar Accepted 11 April 2017 forms were reported in 1992 from the 3.4 Ga Kromberg Formation (KF) of the Kaapvaal craton, South Available online 26 April 2017 Africa, but their origin has remained uncertain. Here we report the first determination of in situ carbon isotopic composition (d13C) of the lenticular structures in the KF (obtained with Secondary Ion Mass Keywords: Spectrometry [SIMS]) as well as the first comparison of these structures to those from the Pilbara, using Archean morphological, isotopic, and sedimentological criteria. Spindle Lenticular Our results support interpretations that the KF forms are bona fide, organic Archean microfossils and Microfossil represent some of the oldest morphologically preserved organisms on Earth.
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