TY - JOUR
T1 - Titanite Mineralization of Microbial Bioalteration Textures in Jurassic Volcanic Glass, Coast Range Ophiolite, California
AU - Izawa, Matthew R.M.
AU - Banerjee, Neil R.
AU - Shervais, John W.
AU - Flemming, Roberta L.
AU - Hetherington, Callum J.
AU - Muehlenbachs, Karlis
AU - Schultz, Cynthia
AU - Das, Debarati
AU - Hanan, Barry B.
N1 - Funding Information:
The authors thank S. Matveev for the help with the X-ray mapping, O. Levner for the help with the stable isotope analyses, M. Grimson for the technical assistance with the SEM at Texas Tech University, and G. Braybrook for the help with the SEM at the University of Alberta. The authors also thank reviewers Huan Cui and Gerhard Franz for thorough and constructive criticism that led to substantial improvements, and M?nica S?nchez-Rom?n for editorial service (and great patience). Funding. MI gratefully acknowledges the support from the Natural Sciences and Engineering Research Council of Canada (NSERC), IODP Canada, the Canadian Astrobiology Training Program (CATp), and the Mineralogical Association of Canada. NB and RF received funding from NSERC. This work was supported by a Research Council of Norway Post-Doctoral Fellowship to NB and grants from the National Science Foundation (JS and BH) and Natural Sciences and Engineering Research Council of Canada (KM).
Funding Information:
MI gratefully acknowledges the support from the Natural Sciences and Engineering Research Council of Canada (NSERC), IODP Canada, the Canadian Astrobiology Training Program (CATp), and the Mineralogical Association of Canada. NB and RF received funding from NSERC. This work was supported by a Research Council of Norway Post-Doctoral Fellowship to NB and grants from the National Science Foundation (JS and BH) and Natural Sciences and Engineering Research Council of Canada (KM).
Publisher Copyright:
© Copyright © 2019 Izawa, Banerjee, Shervais, Flemming, Hetherington, Muehlenbachs, Schultz, Das and Hanan.
PY - 2019/12/3
Y1 - 2019/12/3
N2 - Volcanic glasses are rarely preserved in the rock record, and the quality of preservation generally declines with increasing age. Records preserved in ancient basaltic glasses therefore provide important links between processes operating in the distant past, and those that are active on the Earth today. Microbial colonization has been linked to the formation of characteristic structures in basaltic glass, including tubules and granule-filled tubules, which are thought to be produced by microbially mediated glass dissolution. Structures of similar occurrence and morphology but filled almost entirely with fine-grained titanite have been documented in some ancient metabasalts. It has been suggested that the ancient titanite-mineralized structures are mineralized equivalents of hollow tubules in modern glassy basaltic rocks, but a direct link has not been firmly established. We report the discovery of tubular bioalteration structures in fresh and minimally altered basaltic glasses of middle Jurassic (164 Ma) age from the Stonyford Volcanic Complex (SFVC), Coast Range Ophiolite, California. Tubular structures hosted in unaltered basaltic glass are typically hollow, whilst those in zones of zeolitic alteration are mineralized by titanite. Tubules are continuous across zeolite-glass interfaces, which mark an abrupt change from titanite-filled to hollow tubules, demonstrating that titanite growth occurs preferentially within pre-existing tubular structures. Titanite mineralization in the SFVC represent a link between tubular structures in modern basaltic glass and titanite-mineralized features of similar morphology and spatial distribution in ancient metabasalts. Our observations support a link between textures in modern glassy basaltic rocks and some of the oldest-known putative ichnofossils.
AB - Volcanic glasses are rarely preserved in the rock record, and the quality of preservation generally declines with increasing age. Records preserved in ancient basaltic glasses therefore provide important links between processes operating in the distant past, and those that are active on the Earth today. Microbial colonization has been linked to the formation of characteristic structures in basaltic glass, including tubules and granule-filled tubules, which are thought to be produced by microbially mediated glass dissolution. Structures of similar occurrence and morphology but filled almost entirely with fine-grained titanite have been documented in some ancient metabasalts. It has been suggested that the ancient titanite-mineralized structures are mineralized equivalents of hollow tubules in modern glassy basaltic rocks, but a direct link has not been firmly established. We report the discovery of tubular bioalteration structures in fresh and minimally altered basaltic glasses of middle Jurassic (164 Ma) age from the Stonyford Volcanic Complex (SFVC), Coast Range Ophiolite, California. Tubular structures hosted in unaltered basaltic glass are typically hollow, whilst those in zones of zeolitic alteration are mineralized by titanite. Tubules are continuous across zeolite-glass interfaces, which mark an abrupt change from titanite-filled to hollow tubules, demonstrating that titanite growth occurs preferentially within pre-existing tubular structures. Titanite mineralization in the SFVC represent a link between tubular structures in modern basaltic glass and titanite-mineralized features of similar morphology and spatial distribution in ancient metabasalts. Our observations support a link between textures in modern glassy basaltic rocks and some of the oldest-known putative ichnofossils.
KW - astrobiology
KW - basaltic glass
KW - bioalteration
KW - ichnofossil
KW - titanite
UR - http://www.scopus.com/inward/record.url?scp=85086432951&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85086432951&partnerID=8YFLogxK
U2 - 10.3389/feart.2019.00315
DO - 10.3389/feart.2019.00315
M3 - Article
AN - SCOPUS:85086432951
VL - 7
JO - Frontiers in Earth Science
JF - Frontiers in Earth Science
SN - 2296-6463
M1 - 315
ER -