ORIGINAL ARTICLE
Deconstructing Earth’s oldest ichnofossil record from the Pilbara Craton, West Australia: Implications for seeking life in the Archean subseafloor
Nicola McLoughlin,
David Wacey,
Siyolise Phunguphungu,
Martin Saunders,
Eugene G. Grosch,
Corresponding Author
Nicola McLoughlin
Department of Geology, Rhodes University, Grahamstown, South Africa
Correspondence
Nicola McLoughlin, Department of Geology, Rhodes University, Grahamstown, South Africa.
Email: nicolamcloughlin@hotmail.com
Search for more papers by this authorDavid Wacey
Centre for Microscopy, Characterization and Analysis (CMCA), The University of Western Australia (UWA), Perth, WA, Australia
Search for more papers by this authorSiyolise Phunguphungu
Department of Geology, Rhodes University, Grahamstown, South Africa
Search for more papers by this authorMartin Saunders
Centre for Microscopy, Characterization and Analysis (CMCA), The University of Western Australia (UWA), Perth, WA, Australia
Search for more papers by this authorEugene G. Grosch
Department of Geology, Rhodes University, Grahamstown, South Africa
Search for more papers by this authorNicola McLoughlin,
David Wacey,
Siyolise Phunguphungu,
Martin Saunders,
Eugene G. Grosch,
Corresponding Author
Nicola McLoughlin
Department of Geology, Rhodes University, Grahamstown, South Africa
Correspondence
Nicola McLoughlin, Department of Geology, Rhodes University, Grahamstown, South Africa.
Email: nicolamcloughlin@hotmail.com
Search for more papers by this authorDavid Wacey
Centre for Microscopy, Characterization and Analysis (CMCA), The University of Western Australia (UWA), Perth, WA, Australia
Search for more papers by this authorSiyolise Phunguphungu
Department of Geology, Rhodes University, Grahamstown, South Africa
Search for more papers by this authorMartin Saunders
Centre for Microscopy, Characterization and Analysis (CMCA), The University of Western Australia (UWA), Perth, WA, Australia
Search for more papers by this authorEugene G. Grosch
Department of Geology, Rhodes University, Grahamstown, South Africa
Search for more papers by this authorAbstract
Microtextures of titanite (CaTiSiO5) in exceptionally preserved Archean pillow lavas have been proposed as the earliest examples of microbial ichnofossils. An origin from microbial tunneling of seafloor volcanic glass that is subsequently chloritized and the tunnels infilled by titanite has been argued to record the activities of subseafloor microbes. We investigate the evidence in pillow lavas of the 3.35 Ga Euro Basalt from the Pilbara Craton, Western Australia, to evaluate the biogenicity of the microtextures. We employ a combination of light microscopy and chlorite mineral chemical analysis by EPMA (electron probe micro-analysis) to document the environment of formation and analyze their ultrastructure using FIB-TEM (focussed ion beam combined with transmission electron microscopy) to investigate their mode of growth. Petrographic study of the original and re-collected material identified an expanded range of titanite morphotypes along with early anatase growth forming chains and aggregates of coalesced crystallites in a sub-greenschist facies assemblage. High-sensitivity mapping of FIB lamellae cut across the microtextures confirm that they are discontinuous chains of coalesced crystallites that are highly variable in cross section and contain abundant chlorite inclusions, excluding an origin from the mineralization of previously hollow microtunnels. Comparison of chlorite mineral compositions to DSDP/IODP data reveals that the Euro Basalt chlorites are similar to recent seafloor chlorites. We advance an abiotic origin for the Euro Basalt microtextures formed by spontaneous nucleation and growth of titanite and/anatase during seafloor-hydrothermal metamorphism. Our findings reveal that the Euro Basalt microtextures are not comparable to microbial ichnofossils from the recent oceanic crust, and we question the evidence for life in these Archean lavas. The metamorphic reactions that give rise to the growth of the Euro Basalt microtextures could be commonplace in Archean pillow lavas and need to be excluded when seeking traces of life in the subseafloor on the early Earth.
Supporting Information
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| gbi12399-sup-0010-TableS1.docxWord document, 22.7 KB | Table S1 |
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REFERENCES
- Allwood, A. C., Walter, M. R., Kamber, B. S., Marshall, C. P., & Burch, I. W. (2006). Stromatolite reef from the Early Archaean era of Australia. Nature, 441(7094), 714. https://doi.org/10.1038/nature04764
- Alt, J. C. (1999). Hydrothermal alteration and mineralization of oceanic crust: mineralogy, geochemistry, and processes. In T. Barrie, & M. Hannington (Eds.), Volcanic associated massive sulphide deposits, vol 8 (pp. 133–155). Chelsea, MI: Soc Econ Geol.
- Alt, J. C., Laverne, C., Vanko, T. P., Teagle, D. A. H., Bach, W., Zuleger, E., … Wilkens, R. H. (1996) Hydrothermal alteration of a section of upper oceanic crust in the eastern equatorial Pacific: a synthesis of results from Site 504B (DSDP legs 69, 70, and 83, and ODP legs 111, 137, 140, and 148). In J. C. Alt, H. Kinoshita, L. B. Stokking, & P. J. Michael (Eds.), Proc ODP Sci Res, vol. 148 (pp. 417–434). College Station, TX: Ocean Drilling Program.
10.2973/odp.proc.sr.148.159.1996 Google Scholar
- Banerjee, N. R., Furnes, H., Muehlenbachs, K., Staudigel, H., & de Wit, M. J. (2006). Preservation of ca. 3.4 - 3.5 Ga microbial biomarkers in pillow lavas and hyaloclastites from the Barberton Greenstone Belt, South Africa. Earth and Planetary Science Letters, 241, 707–722.
- Banerjee, N. R., Simonetti, A., Furnes, H., Staudigel, H., Muehlenbachs, K., Heaman, L., & Van Kranendonk, M. J. (2007). Direct dating of Archean microbial ichnofossils. Geology, 35, 487–490. https://doi.org/10.1130/G23534A.1
- Bengtson, S., Rasmussen, B., Ivarsson, M., Muhling, J., Broman, C., Marone, F., … Bekker, A. (2017). Fungus-like mycelial fossils in 2.4-billion-year-old vesicular basalt. Nature Ecology & Evolution, 1, 0141.
- Benzerara, K., Menguy, N., Banerjee, N. R., Tyliszczak, T., Brown, G. E. Jr, & Guyot, F. (2007). Alteration of submarine basaltic glass from the Ontong Java Plateau: A STXM and TEM study. Earth and Planetary Science Letters, 260, 187–200. https://doi.org/10.1016/j.epsl.2007.05.029
- Bridge, N. J., Banerjee, N. R., Mueller, W., Muehlenbachs, K., & Chacko, T. A. (2010). Volcanic habitat for early life preserved in the Abitibi greenstone belt, Canada. Search Results, 179, 88–98.
- Buick, R., Thornett, J. R., McNaughton, N. J., Smith, J. B., Barley, M. E., & Savage, M. (1995). Record of emergent continental crust∼ 3.5 billion years ago in the Pilbara Craton of Australia. Nature, 375(6532), 574.
- Edwards, K. J., Wheat, C. G., & Sylvan, J. B. (2011). Under the sea: Microbial life in volcanic oceanic crust. Nature Reviews Microbiology, 9, 703–712. https://doi.org/10.1038/nrmicro2647
- Fisk, M. R., Crovisier, J. L., & Honnorez, J. (2013). Experimental abiotic alteration of igneous and manufactured glasses. Comptes Rendus Geoscience, 345, 176–184. https://doi.org/10.1016/j.crte.2013.02.001
- Fisk, M. R., Giovannoni, S. J., & Thorseth, I. H. (1998). Alteration of oceanic volcanic glass: Textural evidence of microbial activity. Science, 281, 978–980. https://doi.org/10.1126/science.281.5379.978
- Fisk, M. R., Popa, R., & Wacey, D. (2019). Tunnel formation in basalt glass. Astrobiology, 19, 132–144. https://doi.org/10.1089/ast.2017.1791
- Fliegel, D., Knowles, E., Wirth, R., Templeton, A., Staudigel, H., Muehlenbachs, K., & Furnes, H. (2012). Characterization of alteration textures in Cretaceous oceanic crust (pillow lava) from the N-Atlantic (DSDP Hole 418A) by spatially-resolved spectroscopy. Geochimica Et Cosmochimica Acta, 96, 80–93. https://doi.org/10.1016/j.gca.2012.08.026
- Fliegel, D., Wirth, R., Simonetti, A., Furnes, H., Staudigel, H., Hanski, E., & Muehlenbachs, K. (2010). Septate-tubular textures in 2.0-Ga pillow lavas from the Pechenga Greenstone Belt: A nano-spectroscopic approach to investigate their biogenicity. Geobiology, 8(5), 372–390.
- French, J. E., & Blake, D. F. (2016). Discovery of Naturally Etched Fission Tracks and Alpha-Recoil Tracks in Submarine Glasses: Reevaluation of a Putative Biosignature for Earth and Mars. International Journal of Geophysics, 2016, 1–50. https://doi.org/10.1155/2016/2410573
- Furnes, H., Banerjee, N. R., Muehlenbachs, K., Staudigel, H., & de Wit, M. J. (2004). Early life recorded in Archean pillow lavas. Science, 304, 578–581. https://doi.org/10.1126/science.1095858
- Furnes, H., Banerjee, N. R., Staudigel, H., Muehlenbachs, K., McLoughlin, N., de Wit, M., & Van Kranendonk, M. (2007). Comparing petrographic signatures of bioalteration in recent to Mesoarchean pillow lavas: Tracing subsurface life in oceanic igneous rocks. Precambrian Research, 158, 156–176. https://doi.org/10.1016/j.precamres.2007.04.012
- Furnes, H., Staudigel, H., Thorseth, I. H., Torsvik, T., Muehlenbachs, K., & Tumyr, O. (2001). Bioalteration of basaltic glass in the oceanic crust. Geochemistry, Geophysics, Geosystems, 2(8), n/a–n/a. https://doi.org/10.1029/2000GC000150
10.1029/2000GC000150 Google Scholar
- Grosch, E. G., & Mcloughlin, N. (2014). Reassessing the biogenicity of Earth's oldest trace fossil with implications for biosignatures in the search for early life. Proceedings of the National Academy of Sciences, 111, 8380–8385. https://doi.org/10.1073/pnas.1402565111
- Grosch, E. G., & McLoughlin, N. (2015). Questioning the biogenicity of titanite mineral trace fossils in Archean pillow lavas. Proceedings of the National Academy of Sciences, 112(24), E3090–E3091. https://doi.org/10.1073/pnas.1506995112
- Grosch, E. G., McLoughlin, N., Lanari, P., Erambert, M., & Vidal, O. (2014). Microscale mapping of alteration conditions and potential biosignatures in basaltic-ultramafic rocks on early Earth and beyond. Astrobiology, 14, 216–228. https://doi.org/10.1089/ast.2013.1116
- Grosch, E. G., Muñoz, M., Mathon, O., & McLoughlin, N. (2017). Earliest microbial trace fossils in Archaean pillow lavas under scrutiny: New micro-X-ray absorption near-edge spectroscopy, metamorphic and morphological constraints. Geological Society, London, Special Publications, 448(1), 57–70. https://doi.org/10.1144/SP448.8
10.1144/SP448.8 Google Scholar
- Hey, M. H. (1954). A new review of the chlorites. Mineralogical Magazine and Journal of the Mineralogical Society, 30(224), 277–292. https://doi.org/10.1180/minmag.1954.030.224.01
- Hickman, A. H. (2008). Regional review of the 3426-3350 Ma Strelley Pool Formation, Pilbara Craton, Western Australia. Geological Survey of Western Australia Record 2008/15, 27 p.
- Ishizuka, H. (1985). Prograde metamorphism of the Horokanai ophiolite in the Kamuikotan Zone, Hokkaido, Japan. Journal of Petrology, 26(2), 391–417. https://doi.org/10.1093/petrology/26.2.391
- Izawa, M., Banerjee, N. R., Shervais, J. W., Flemming, R. L., Hetherington, C. J., Muehlenbachs, K., … Hanan, B. B. (2019). Titanite mineralization of Microbial Bioalteration textures in Jurassic Volcanic Glass, Coast Range Ophiolite, California. Frontiers in Earth Science, 7, 315.
- Javaux, E. J. (2019). Challenges in evidencing the earliest traces of life. Nature, 572(7770), 451–460.
- Jolly, W. T., & Smith, R. E. (1972). Degradation and metamorphic differentiation of the Keweenawan tholeiitic lavas of northern Michigan, USA. Journal of Petrology, 13(2), 273–309. https://doi.org/10.1093/petrology/13.2.273
- Kitajima, K., Maruyama, S., Utsunomiya, S., & Liou, J. G. (2001). Seafloor hydrothermal alteration at an Archaean mid-ocean ridge. Journal of Metamorphic Geology, 19(5), 583–599. https://doi.org/10.1046/j.0263-4929.2001.00330.x
- Knowles, E., Wirth, R., & Templeton, A. (2012). A Comparative analysis of potential biosignatures in basalt glass by FIB-TEM. Chemical Geology, 331, 165–175. https://doi.org/10.1016/j.chemgeo.2012.08.028
- Kranendonk, V. (2000 ). Geology of the North Shaw 1:100 000 sheet: Western Australia Geological Survey, 1:100 000 Geological Series Explanatory Notes, 86 p.
- Laird, J. (1988). Chlorites: metamorphic petrology. In S. W. Bailey (Ed.), Hydrous phyllosilicates (exclusive of micas), vol. 19 (pp. 405–453). Chantilly, VA: Mineralogical Society of America.
- Laverne, C., Vanko, D. A., Tartarotti, P., & Alt, J. C. (1995). Chemistry and geothermometry of secondary minerals from the deep sheeted dike complex, Hole 504B. Proceedings of the Ocean Drilling Program, Scientific Results, 137–140, 167–189.
- Lepot, K., Benzerara, K., & Philippot, P. (2011). Biogenic versus metamorphic origins of diverse microtubes in 2.7 Gyr old volcanic ashes: Multi-scale investigations. Earth and Planetary Science Letters, 312, 37–47. https://doi.org/10.1016/j.epsl.2011.10.016
- Lepot, K., Philippot, P., Benzerara, K., & Wang, Y. (2009). Garnet-filled trails associated with carbonaceous matter mimicking microbial filaments in Archean basalt. Geobiology, 7, 393–402. https://doi.org/10.1111/j.1472-4669.2009.00208.x
- McCollom, T. M., & Donaldson, C. (2019). Experimental constraints on abiotic formation of tubules and other proposed biological structures in subsurface volcanic glass. Astrobiology, 19(1), 53–63. https://doi.org/10.1089/ast.2017.1811
- McLoughlin, N., Furnes, H., Banerjee, N. R., Muehlenbachs, K., & Staudigel, H. (2009). Ichnotaxonomy of microbial trace fossils in volcanic glass. Journal of the Geological Society, 166(1), 159–169. https://doi.org/10.1144/0016-76492008-049
- McLoughlin, N., & Grosch, E. G. (2015). A hierarchical system for evaluating the biogenicity of metavolcanic-and ultramafic-hosted microalteration textures in the search for extraterrestrial life. Astrobiology, 15(10), 901–921. https://doi.org/10.1089/ast.2014.1259
- McLoughlin, N., Grosch, E. G., Kilburn, M. R., & Wacey, D. (2012). Sulfur isotope evidence for a Paleoarchean subseafloor biosphere, Barberton, South Africa. Geology, 40(11), 1031–1034. https://doi.org/10.1130/G33313.1
- McLoughlin, N., Staudigel, H., Furnes, H., Eickmann, B., & Ivarsson, M. (2010). Mechanisms of microtunneling in rock substrates: Distinguishing endolithic biosignatures from abiotic microtunnels. Geobiology, 8, 245–255. https://doi.org/10.1111/j.1472-4669.2010.00243.x
- Nelson, D. R. (2005). Compilation of geochronology data, June 2005 update: Western Australia Geological Survey, CD - ROM.
- Nimis, P., Tesalina, S. G., Omenetto, P., Tartarotti, P., & Lerouge, C. (2004). Phyllosilicate minerals in the hydrothermal mafic–ultramafic-hosted massive-sulfide deposit of Ivanovka (southern Urals): Comparison with modern ocean seafloor analogues. Contributions to Mineralogy and Petrology, 147(3), 363–383. https://doi.org/10.1007/s00410-004-0565-3
- Orcutt, B. N., Sylvan, J. B., Knab, N. J., & Edwards, K. J. (2011). Microbial ecology of the dark ocean above, at and below the seafloor. Microbiology and Molecular Biology Reviews, 75, 361–422. https://doi.org/10.1128/MMBR.00039-10
- Pedersen, L. E. R., McLoughlin, N., Vullum, P. E., & Thorseth, I. H. (2015). Abiotic and candidate biotic micro-alteration textures in subseafloor basaltic glass: A high-resolution in-situ textural and geochemical investigation. Chemical Geology, 410, 124–137. https://doi.org/10.1016/j.chemgeo.2015.06.005
- Schiffman, P., & Day, H. W. (1999). Petrological methods for the study of low-grade metabasites. In M. Frey, & D. Robinson (Eds.), Low grade metamorphism (pp. 108–142). Malden, MA: Blackwell.
- Shikazono, N., & Kawahata, H. (1987). Compositional differences in chlorite from hydrothermally altered rocks and hydrothermal ore deposits. Canadian Mineralogist, 25, 465–474.
- Staudigel, H., Chastain, R., Yaynos, A., & Bourcier, R. (1995). Biologically mediated dissolution of glass. Chemical Geology, 126, 147–154. https://doi.org/10.1016/0009-2541(95)00115-X
- Staudigel, H., Furnes, H., & DeWit, M. (2015). Paleoarchean trace fossils in altered volcanic glass. Proceedings of the National Academy of Sciences, 112(22), 6892–6897. https://doi.org/10.1073/pnas.1421052112
- Staudigel, H., Furnes, H., McLoughlin, N., Banerjee, N. R., Connell, L. B., & Templeton, A. (2008). 3.5 billion years of glass bioalteration: Volcanic rocks as a basis for microbial life? Earth Science Review, 89, 156–176.
- Teagle, D. A., & Alt, J. C. (2004). Hydrothermal alteration of basalts beneath the Bent Hill massive sulfide deposit, Middle Valley, Juan de Fuca Ridge. Economic Geology, 99(3), 561–584. https://doi.org/10.2113/gsecongeo.99.3.561
- Terabayashi, M., Masada, Y., & Ozawa, H. (2003). Archean ocean-floor metamorphism in the North Pole area, Pilbara Craton, Western Australia. Precambrian Research, 127(1–3), 167–180. https://doi.org/10.1016/S0301-9268(03)00186-4
- Thorseth, I. H. (2011) Basalt (Glass, Endolith). In J. Reithner, & V. Thiel (Eds.), Encyclopedia of Geobiology, Encyclopedia of Earth Sciences Series (pp. 103–111). London, UKSpringer.
10.1007/978-1-4020-9212-1_21 Google Scholar
- Thorseth, I. H., Torsvik, T., Furnes, H., & Muehlenbachs, K. (1995). Microbes play an important role in the alteration of oceanic crust. Chemical Geology, 126, 137–146. https://doi.org/10.1016/0009-2541(95)00114-8
- Van Kranendonk, M. J. (2006). Volcanic degassing, hydrothermal circulation and the flourishing of early life on Earth: A review of the evidence from c. 3490–3240 Ma rocks of the Pilbara Supergroup, Pilbara Craton, Western Australia. Earth-Science Reviews, 74(3), 197–240.
- Van Kranendonk, M. J., Hickman, A. H., Smithies, R. H., Nelson, D. N., & Pike, G. (2002). Geology and tectonic evolution of the Archaean North Pilbara terrain, Pilbara Craton, Western Australia. Economic Geology, 97, 695–732.
- Van Kranendonk, M. J., Philippot, P., Lepot, K., Bodorkos, S., & Pirajno, F. (2008). Geological setting of Earth’s oldest fossils in the ca. 3.5 Ga Dresser Formation, Pilbara Craton, Western Australia. Precambrian Research, 167, 93–124.
- Wacey, D., Fisk, M., Saunders, M., Eiloart, K., & Kong, C. (2017). Critical testing of potential cellular structures within microtubes in 145 Ma volcanic glass from the Argo Abyssal Plain. Chemical Geology, 466, 575–587. https://doi.org/10.1016/j.chemgeo.2017.07.006
- Wacey, D., McLoughlin, N., Saunders, M., & Kong, C. (2014). The nano-scale anatomy of a complex carbon-lined microtube in volcanic glass from the~ 92 Ma Troodos Ophiolite, Cyprus. Chemical Geology, 363, 1–12. https://doi.org/10.1016/j.chemgeo.2013.10.028
- Walton, A. W., & Schiffman, P. (2003). Alteration of hyaloclastites in the HSDP 2 Phase 1 Drill Core 1. Description and paragenesis. Geochemistry, Geophysics, Geosystems, 4(5), n/a–n/a. https://doi.org/10.1029/2002GC000368
- Zhang, Z., & Goloubic, S. (1987). Endolithic microfossils (cyanophyta) from early Proterozoic Stromatolites, Hebei China. Acta Ecologica Sinica, 4, 1–12.
