Continental extensional setting for the Archean Belingwe Greenstone Belt, Zimbabwe

Hunter, M. A.; Bickle, M. J.; Nisbet, E. G.; Martín, Alexis; Chapman, H. J.

doi:10.1130/0091-7613(1998)026<0883:cesfta>2.3.co;2

Cited by 77 publications

(40 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…3). A possible interpretation is that precursor OM of these kerogens thrived in warm waters undergoing intense evaporation, which is consistent with the continental depositional environments proposed for these formations (Buck, 1980;Hunter et al, 1998). …”

Section: Geochemical Perspectives Letterssupporting

confidence: 53%

Warm Archaean oceans reconstructed from oxygen isotope composition of early-life remnants

Tartèse¹,

Chaussidon²,

Gurenko³

et al. 2016

Geochem. Persp. Let.

View full text Add to dashboard Cite

doi: 10.7185/geochemlet.1706 Deciphering the surface conditions on the Earth during Archean times (> 2.5 billion years ago -Ga) is crucial to constrain the conditions that promoted the development of life. The progressive shift through time of the oxygen isotopic compositions of Precambrian siliceous sediments -the so-called cherts -has been interpreted as indicating a secular decrease of seawater temperature by 50-80 °C from the early Archean to the present-day. However, this interpretation has been questioned, notably because it assumes that the seawater oxygen isotopic composition has remained globally constant since 3.5 Ga, though this has never been tested by direct isotopic measurements on Archean samples. Here we report measurements of the oxygen isotopic composition of carbonaceous matter indigenous to Precambrian cherts up to ca. 3.5 Ga. These new results demonstrate that the oxygen isotope composition of seawater during most of the Precambrian remained around 0 ± 5 ‰, which is consistent with the composition of present day seawater. Combined with the chert oxygen isotope composition record, this indicates that ca. 3.5 Ga ago ocean bottom-water temperatures were ~50-60 °C higher than today.

show abstract

Section: Geochemical Perspectives Letterssupporting

confidence: 53%

Warm Archaean oceans reconstructed from oxygen isotope composition of early-life remnants

Tartèse¹,

Chaussidon²,

Gurenko³

et al. 2016

Geochem. Persp. Let.

View full text Add to dashboard Cite

show abstract

“…This Member is extensive and stratigraphic evidence suggests that it may originally have been widespread over a few square kilometres. This precludes origin as a localized volcanic-exhalative mat, although rare-earth element (REE) data (Hunter et al 1998) indicate that distal volcanism may have enriched the water in metals and sulphur species. Komatiite lavas and basalts overlie the Manjeri Fm.…”

Section: Sampling and Isotopic Methodologymentioning

confidence: 99%

“…The Manjeri Fm. succession continues with the clastic Rubweruchena Member (Hunter et al 1998), followed by a sulphide^carbon^chert horizon, the Jimmy Member, that has ¢ne laminations, which may have been laid down in somewhat deeper water, below the wave base. The Jimmy Member is sheared and its origin is disputed (Kusky & Winsky 1995), but we consider the sequence to be in situ and coherent (Bickle & Nisbet 1993).…”

Section: Sampling and Isotopic Methodologymentioning

confidence: 99%

See 1 more Smart Citation

Antiquity of the biological sulphur cycle: evidence from sulphur and carbon isotopes in 2700 million–year–old rocks of the Belingwe Belt, Zimbabwe

Grassineau

Nisbet

Bickle

et al. 2001

Proc. R. Soc. Lond. B

Self Cite

View full text Add to dashboard Cite

Sulphur and carbon isotopic analyses on small samples of kerogens and sulphide minerals from biogenic and non-biogenic sediments of the 2.7Â10 9 years(Ga)-old Belingwe Greenstone Belt (Zimbabwe) imply that a complex biological sulphur cycle was in operation. Sulphur isotopic compositions display a wider range of biological fractionation than hitherto reported from the Archaean. Carbon isotopic values in kerogen record fractionations characteristic of rubisco activity, methanogenesis and methylotrophy, and possibly anoxygenic photosynthesis. Carbon and sulphur isotopic fractionations have been interpreted in terms of metabolic processes in 2.7 Ga prokaryote mat communities, and indicate the operation of a diverse array of metabolic processes. The results are consistent with models of early molecular evolution derived from ribosomal RNA.

show abstract

“…It is younger than an underlying 2831 ± 6 Ma greenstone succession, but older than or in part contemporaneous with a structurally overlying, ca. 2.7 Ga ultramafic to mafic subaqueous lava plain sequence 22,23 . The Manjeri Formation has been correlated with similar successions in other greenstone belts of Zimbabwe 24 .…”

Section: Ca 27 Ga Manjeri Formation Zimbabwementioning

confidence: 99%

Evidence for oxygenic photosynthesis half a billion years before the Great Oxidation Event

et al. 2014

View full text Add to dashboard Cite

Method Summary:Rocks were collected from either drill core or surface outcrop without obvious weathering. Exterior surfaces were removed. Samples were powdered in a tungsten carbide mill from chips that were picked to avoid veins. Major element concentrations were determined using either an ICP-MS (Agilent 7500ce Series, or Thermo Element2) or an ICP-AES (Iris Advantage) after a three-acid dissolution or a metaborate fusion, respectively. Accuracy and precision for major element analyses was based on duplicates of the geostandards IF-G, SDO-1, and BHVO-1, and estimated error is less than 5%. For Mo isotopes, powdered samples were digested with concentrated HNO 3 + HF and HNO 3 + HCl, and then the samples were evaporated and dissolved with 7 mol/L HCl.

show abstract

Continental extensional setting for the Archean Belingwe Greenstone Belt, Zimbabwe

Cited by 77 publications

References 0 publications

Warm Archaean oceans reconstructed from oxygen isotope composition of early-life remnants

Warm Archaean oceans reconstructed from oxygen isotope composition of early-life remnants

Antiquity of the biological sulphur cycle: evidence from sulphur and carbon isotopes in 2700 million–year–old rocks of the Belingwe Belt, Zimbabwe

Evidence for oxygenic photosynthesis half a billion years before the Great Oxidation Event

Contact Info

Product

Resources

About