Role for microorganisms in the formation of iridium anomalies

Dyer, Betsey Dexter; Lyalikova, Natalia N.; Murray, Daniel P.; Doyle, Michael Sean; Колесов, Г. М.; Krumbein, Wolfgang E.

doi:10.1130/0091-7613(1989)017<1036:rfmitf>2.3.co;2

Cited by 28 publications

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“…Huge deposits of iron oxides and carbonates ; Dahanayake and Krumbein, 1986) have been identified as largely microbially mediated deposits (microbialites). A similar origin has also been indicated for Precambrian sedimentary gold and uranium deposits and even for iridium-enriched laminated deposits (Dyer et al, 1984(Dyer et al, , 1988(Dyer et al, , 1989.…”

supporting

confidence: 68%

Geophysiology of mineral deposits ‐ a model for a biological driving force of global changes through Earth history

Krumbein

Schellnhuber

1992

Terra Nova

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The upper mantle, crust, hydrosphere and atmosphere of Earth are kept in a geophysical, geochemical and thermodynamical state far from astrophysical and planetary equilibrium. The system oscillates around a quasi-stable centre following laws governing dissipative or dynamic systems. The energy and materials necessary for such global pseudoequilibria are fed in, stored and released on a geological time-scale by (a) the energy and electron channelling processes of photosynthesis, respiration and fermentation, (b) biologically controlled accumulation of energy and matter into crustal reservoirs and much later (c) release of the latter from crust and upper mantle into surface-related geotectonical and geochemical cycles. Phototrophic and chemorganotrophic bacterial microorganisms of microbial mats, potential stromatolites or microbialites are capable of anoxygenic and oxygenic photosynthesis, of aerobic and anaerobic respiration and of organic and inorganic fermentation, i.e. disproportioning of energy-

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confidence: 68%

Geophysiology of mineral deposits ‐ a model for a biological driving force of global changes through Earth history

Krumbein

Schellnhuber

1992

Terra Nova

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“…As the source material in both sections should be quite similar, these differences can be explained in terms of a different diagenetic evolution of the boundary layer material. The mechanism of PGE behaviour and transport in low‐temperature solutions is still poorly known, although Ir remobilization has been reported in relation to microbial activity ( Dyer et al ., 1989 ) and in suboxic conditions ( De Lange et al ., 1991 ). In other K/T boundary sections, Ir concentrations vary widely from place to place (e.g.…”

Section: Discussionmentioning

confidence: 99%

Positive Eu anomaly development during diagenesis of the K/T boundary ejecta layer in the Agost section (SE Spain): implications for trace‐element remobilization

1999

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K/T boundary geochemical anomalies have been used previously to support the impact event at the end of the Cretaceous. However, impact models and assessment of the extraterrestrial contribution to the boundary sediments should also consider the diagenetic alteration of the impact signatures. Mineralogical and geochemical studies centring on redox proxies reveal differences in trace‐element concentrations at Agost and Caravaca (SE Spain), two of the most complete K/T boundary sections. These differences probably derive from variations in the diagenetic evolution of the ejecta layer. Several redox proxies, such as extensive pyrite formation, high authigenic uranium concentration and positive Eu anomalies, indicate very strong reducing conditions at Agost. Positive Eu anomalies are extremely unusual in sediments, and in this case are interpreted to indicate a highly reducing environment. In such conditions, certain trace elements such as Ir, may have been remobilized, thereby masking the original signature of the impact.

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“…For example, the ability of some bacteria and fungi to concentrate iridium from solution and to dissolve iridium from various source rocks has been established (Dyer et al, 1989). Watterson's (1991) documentation of the contribution of Pedomicrobium-like budding bacteria to gold metallogeny suggests the importance of microorganisms in the geochemical cycle of gold.…”

Section: Discussionmentioning

confidence: 99%

Accumulation of gold in the sheath ofPlectonema terebrans(filamentous marine cyanobacteria)

Dyer

Krumbein

Mossman

1994

Geomicrobiology Journal

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Role for microorganisms in the formation of iridium anomalies

Cited by 28 publications

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Geophysiology of mineral deposits ‐ a model for a biological driving force of global changes through Earth history

Geophysiology of mineral deposits ‐ a model for a biological driving force of global changes through Earth history

Positive Eu anomaly development during diagenesis of the K/T boundary ejecta layer in the Agost section (SE Spain): implications for trace‐element remobilization

Accumulation of gold in the sheath ofPlectonema terebrans(filamentous marine cyanobacteria)

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