Biogenicity of an Early Quaternary iron formation, Milos Island, Greece
(2015) In Geobiology 13(3). p.225-244- Abstract
- A 2.0-million-year-old shallow-submarine sedimentary deposit on Milos Island, Greece, harbours an unmetamorphosed fossiliferous iron formation (IF) comparable to Precambrian banded iron formations (BIFs). This Milos IF holds the potential to provide clues to the origin of Precambrian BIFs, relative to biotic and abiotic processes. Here, we combine field stratigraphic observations, stable isotopes of C, S and Si, rock petrography and microfossil evidence from a 5-m-thick outcrop to track potential biogeochemical processes that may have contributed to the formation of the BIF-type rocks and the abrupt transition to an overlying conglomerate-hosted IF (CIF). Bulk C-13 isotopic compositions lower than -25 parts per thousand provide evidence... (More)
- A 2.0-million-year-old shallow-submarine sedimentary deposit on Milos Island, Greece, harbours an unmetamorphosed fossiliferous iron formation (IF) comparable to Precambrian banded iron formations (BIFs). This Milos IF holds the potential to provide clues to the origin of Precambrian BIFs, relative to biotic and abiotic processes. Here, we combine field stratigraphic observations, stable isotopes of C, S and Si, rock petrography and microfossil evidence from a 5-m-thick outcrop to track potential biogeochemical processes that may have contributed to the formation of the BIF-type rocks and the abrupt transition to an overlying conglomerate-hosted IF (CIF). Bulk C-13 isotopic compositions lower than -25 parts per thousand provide evidence for biological contribution by the Calvin and reductive acetyl-CoA carbon fixation cycles to the origin of both the BIF-type and CIF strata. Low S levels of 0.04 wt.% combined with S-34 estimates of up to 18 parts per thousand point to a non-sulphidic depository. Positive Si-30 records of up to +0.53 parts per thousand in the finely laminated BIF-type rocks indicate chemical deposition on the seafloor during weak periods of arc magmatism. Negative Si-30 data are consistent with geological observations suggesting a sudden change to intense arc volcanism potentially terminated the deposition of the BIF-type layer. The typical Precambrian rhythmic rocks of alternating Fe- and Si-rich bands are associated with abundant and spatially distinct microbial fossil assemblages. Together with previously proposed anoxygenic photoferrotrophic iron cycling and low sedimentary N and C potentially connected to diagenetic denitrification, the Milos IF is a biogenic submarine volcano-sedimentary IF showing depositional conditions analogous to Archaean Algoma-type BIFs. (Less)
Please use this url to cite or link to this publication:
https://lup.lub.lu.se/record/5401286
- author
- Fru, E. Chi ; Ivarsson, M. ; Kilias, S. P. ; Frings, Patrick LU ; Hemmingsson, C. ; Broman, C. ; Bengtson, S. and Chatzitheodoridis, E.
- organization
- publishing date
- 2015
- type
- Contribution to journal
- publication status
- published
- subject
- in
- Geobiology
- volume
- 13
- issue
- 3
- pages
- 225 - 244
- publisher
- Wiley-Blackwell
- external identifiers
-
- wos:000352728600002
- scopus:84927082882
- pmid:25645266
- ISSN
- 1472-4669
- DOI
- 10.1111/gbi.12128
- language
- English
- LU publication?
- yes
- id
- 2b71788c-5609-454f-a365-c67aa410e9a6 (old id 5401286)
- date added to LUP
- 2016-04-01 11:14:42
- date last changed
- 2022-02-03 00:49:31
@article{2b71788c-5609-454f-a365-c67aa410e9a6,
abstract = {{A 2.0-million-year-old shallow-submarine sedimentary deposit on Milos Island, Greece, harbours an unmetamorphosed fossiliferous iron formation (IF) comparable to Precambrian banded iron formations (BIFs). This Milos IF holds the potential to provide clues to the origin of Precambrian BIFs, relative to biotic and abiotic processes. Here, we combine field stratigraphic observations, stable isotopes of C, S and Si, rock petrography and microfossil evidence from a 5-m-thick outcrop to track potential biogeochemical processes that may have contributed to the formation of the BIF-type rocks and the abrupt transition to an overlying conglomerate-hosted IF (CIF). Bulk C-13 isotopic compositions lower than -25 parts per thousand provide evidence for biological contribution by the Calvin and reductive acetyl-CoA carbon fixation cycles to the origin of both the BIF-type and CIF strata. Low S levels of 0.04 wt.% combined with S-34 estimates of up to 18 parts per thousand point to a non-sulphidic depository. Positive Si-30 records of up to +0.53 parts per thousand in the finely laminated BIF-type rocks indicate chemical deposition on the seafloor during weak periods of arc magmatism. Negative Si-30 data are consistent with geological observations suggesting a sudden change to intense arc volcanism potentially terminated the deposition of the BIF-type layer. The typical Precambrian rhythmic rocks of alternating Fe- and Si-rich bands are associated with abundant and spatially distinct microbial fossil assemblages. Together with previously proposed anoxygenic photoferrotrophic iron cycling and low sedimentary N and C potentially connected to diagenetic denitrification, the Milos IF is a biogenic submarine volcano-sedimentary IF showing depositional conditions analogous to Archaean Algoma-type BIFs.}},
author = {{Fru, E. Chi and Ivarsson, M. and Kilias, S. P. and Frings, Patrick and Hemmingsson, C. and Broman, C. and Bengtson, S. and Chatzitheodoridis, E.}},
issn = {{1472-4669}},
language = {{eng}},
number = {{3}},
pages = {{225--244}},
publisher = {{Wiley-Blackwell}},
series = {{Geobiology}},
title = {{Biogenicity of an Early Quaternary iron formation, Milos Island, Greece}},
url = {{http://dx.doi.org/10.1111/gbi.12128}},
doi = {{10.1111/gbi.12128}},
volume = {{13}},
year = {{2015}},
}