Preservation of organic carbon in dolomitized Cambrian stromatolites and implications for microbial biosignatures in diagenetically replaced carbonate rock
| dc.contributor.author | Murphy, Ashley E. | |
| dc.contributor.author | Wieman, Scott | |
| dc.contributor.author | Gross, Juliane | |
| dc.contributor.author | .Stern, Jennifer C | |
| dc.contributor.author | Steele, Andrew | |
| dc.contributor.author | Glamoclija, Mihaela | |
| dc.date.accessioned | 2022-02-07T19:39:32Z | |
| dc.date.available | 2022-02-07T19:39:32Z | |
| dc.date.issued | 2020-12 | |
| dc.description.abstract | Stromatolites have been a major focus in the search for ancient microbial life, however, the organic carbon biosignatures of dolomitized stromatolites have not yet been fully characterized or correlated with their dolomitizing conditions. Although dolomitization rarely preserves microbial morphology, the presence of organic carbon can provide valuable information for characterization of fossils' biogenicity, syngenicity, and indigeneity to their host rock. The Cambrian Allentown Formation in New Jersey, USA, is an excellent example of dolomitized stromatolites and thrombolites containing diagenetically modified microbial biosignatures. Based on XRD and EPMA data, the dolomite composition is typically stoichiometric, with varying degrees of cationic ordering. The outcrop underwent early dolomitization in a marginal-marine setting and later burial diagenesis resulting in multi-generational dolomite formation: (1) microspar dolomite formed by early diagenetic replacement at or near the surface, (2) zoned dolomite formed penecontemporaneously with the microspar phase as rhombohedral crystals by infilling primary pore spaces within the microspar matrix. The rhombic crystals continued to grow outward in alternating stages of Fe-enriched and -depleted fluids, which were preserved in zoned rims and revealed by cathodoluminescence, and (3) saddle dolomite formed during late stage deep burial with Fe- and Mn-rich fluids, and occurs as a void-filling, high-temperature phase. Organic carbon, characterized using confocal Raman microscopy, has an exclusive distribution within the microspar dolomite, and the D and G bands' characteristics reveal similar thermal alteration to the host rock, indicating that the mapped organic carbon is indigenous and syngenetic with the Cambrian carbonates. The findings presented in this study reveal organic matter found within microspar of various dolomitized facies deriving from different source pools of organic carbon. This study sheds light on biosignatures in secondary dolostones and may aid biosignature detection in older carbonate rocks on Earth and Mars. | en_US |
| dc.description.sponsorship | We are grateful to Alexander Gates and Michael Kalczynski for their assistance with field trip logistics and sample collection. This study was funded by NASA ASTEP (NNX14AT28G to 836 M.G.) and NASA NAI ENIGMA – Rutgers University (80NSSC18M0093). | en_US |
| dc.description.uri | https://www.sciencedirect.com/science/article/pii/S0037073820301925 | en_US |
| dc.format.extent | 56 pages | en_US |
| dc.genre | journal articles | en_US |
| dc.genre | preprints | en_US |
| dc.identifier | doi:10.13016/m2qvwa-pwyw | |
| dc.identifier.citation | "Murphy, Ashley E. et al. Preservation of organic carbon in dolomitized Cambrian stromatolites and implications for microbial biosignatures in diagenetically replaced carbonate rock. Sedimentary Geology 410 (December 2020), 105777. https://doi.org/10.1016/j.sedgeo.2020.105777" | en_US |
| dc.identifier.uri | https://doi.org/10.1016/j.sedgeo.2020.105777 | |
| dc.identifier.uri | http://hdl.handle.net/11603/24131 | |
| dc.language.iso | en_US | en_US |
| dc.publisher | Elsevier | en_US |
| dc.relation.isAvailableAt | The University of Maryland, Baltimore County (UMBC) | |
| dc.relation.ispartof | UMBC Center for Space Sciences and Technology | |
| dc.relation.ispartof | UMBC Faculty Collection | |
| dc.rights | This item is likely protected under Title 17 of the U.S. Copyright Law. Unless on a Creative Commons license, for uses protected by Copyright Law, contact the copyright holder or the author. | en_US |
| dc.rights | Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0) | * |
| dc.rights | Access to this item will begin on 12/30/22. | |
| dc.rights.uri | https://creativecommons.org/licenses/by-nc-nd/4.0/ | * |
| dc.title | Preservation of organic carbon in dolomitized Cambrian stromatolites and implications for microbial biosignatures in diagenetically replaced carbonate rock | en_US |
| dc.type | Text | en_US |
| dcterms.creator | https://orcid.org/0000-0002-6415-5293 | en_US |