Mn- and Fe-rich black travertine shrubs; bacterially (and nanobacterially) induced precipitates

Chafetz, Henry S.; Akdim, Brahim; Julià, Ramón; Reid, A. M.

doi:10.2110/jsr.68.404

Cited by 84 publications

(67 citation statements)

References 28 publications

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“…The origin of Frutexites remains a matter of ongoing controversy, as they have no obvious modern marine analogues; the only reports of contemporary, subfossil Frutexites shrubs come from some alkaline lakes (Kaźmierczak and Kempe 2006;Kaźmierczak et al 2011), and similar structures have been reported from modern deserts (desert varnish; Krumbein and Jens 1981), terrestrial caves and tunnels (Rodríguez-Martínez et al 2011a) and hot springs (black travertine shrubs; Chafetz et al 1998). In addition, numerous examples of calcitic microstromatolites are morphologically similar to Frutexites, but lack Fe-and Mn-enrichment (e.g., Chafetz and Folk 1984;Chafetz and Guidry 1999), which further extends the variety of non-marine settings favoring the development of Frutexites-like structures.…”

Section: Introductionmentioning

confidence: 97%

Frutexites encrustations on rugose corals (Middle Devonian, southern Morocco): complex growth of microbial microstromatolites

Jakubowicz

Bełka

Berkowski

2013

Facies

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Section: Introductionmentioning

confidence: 97%

Frutexites encrustations on rugose corals (Middle Devonian, southern Morocco): complex growth of microbial microstromatolites

Jakubowicz

Bełka

Berkowski

2013

Facies

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“…Changes in pH at a site could be the result of: (1) changes in the composition of the waters issuing from the spring, (2) differences in the volume of water such that degassing of CO 2 (which results in pH changes) takes place closer to, or farther from, the spring, or (3) changes in the location, and thus distance, of the spring from the site of precipitation (Chafetz and Lawrence 1994). As a result, it can be concluded that, as pH increased downstream from the springs in the Ab Ask area, deposition of Fe-oxides and carbonates must have been sequentially favored, similarly to the successive precipitation of those minerals in southern Morocco reported by Chafetz et al (1998).…”

Section: Central European Geology 55 2012mentioning

confidence: 85%

“…On the other hand, laminations in travertine could also form by daily or seasonal cycle in cyanobacterial metabolism (Chafetz et al 1998). Folk et al (1985) and Guo and Riding (1992) reported laminae from Italian travertine and attributed their origin to changes in the activity of photosynthetic bacteria due to diurnal variations in the intensity of sunlight and probably temperature.…”

Section: Central European Geology 55 2012mentioning

confidence: 99%

Mineralogy and stable isotope geochemistry of the Ab Ask travertines in Damavand geothermal field, Northeast Tehran, Iran

Javanmard¹,

Tutti²,

Omidian³

et al. 2012

Central European Geology

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The Ab Ask mineral springs are located 85 km northeast of Tehran, in the southern range of the Damavand volcano. Deposits of these calcareous springs are mainly precipitated as travertine. Petrographical, mineralogical, and stable isotope studies were conducted on different types of travertine to determine their genesis and factors that govern carbonate precipitation. Based on sedimentation consequence and lithofacies these travertines are categorized as first type (fresh travertine), second type (fissure-ridge, dam, and cascade), and third type (laminated) travertines, illustrating a specific condition of formation, deposition and diagenesis. Combined XRD and microscopic investigations show that the Ab Ask travertines are is composed of about 95 % calcite and a minor amount of quartz along with iron oxide impurities. The origin and transport of springs water from which travertine was precipitated are elucidated by 13 C and 18 O isotopic studies of the travertines.δ 18 O and δ 13 C values of travertines increase (from -13.0 to -6.3‰ VPDB and from 6 to 9.8‰ VPDB, respectively) with increasing distance from the spring orifice. This significant increase is attributed to temperature decrease, rapid degassing of CO 2 , and biological activities. It seems that CO 2 content of these fluids may have originated from limestone decarbonation. Based on the integrated petrographic and stable isotope study, the Ab Ask travertines can could be thermogenic in origin.

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“…The presence of gas bubbles and micropores in the dendrites and druse stands in sharp contrast to their absence in the surrounding quartz crystals (Figure 7), providing further evidence for biological nucleation (Chafetz and Guidry, 1999). In addition, the organized chains and interconnected clumps of clay spheres containing acicular crystal needles ( Figures 7C, 7D) are commonly found in bacterially produced branching masses in travertines (Chafetz et al, 1998), and microbes are known to play an important role in clay sphere formation (Tazaki, 2005 and references therein). Clays have also been shown to act as nucleation surfaces for modern Mn and Fe oxides (Xu and Lee, in press).…”

Section: Mountain City Windowmentioning

confidence: 89%

New insight into the origin of manganese oxide ore deposits in the Appalachian Valley and Ridge of northeastern Tennessee and northern Virginia, USA

Carmichael

Doctor

Wilson

et al. 2017

Geological Society of America Bulletin

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Manganese oxide deposits have long been observed in association with carbonates within the Appalachian Mountains, but their origin has remained enigmatic for well over a century. Ore deposits of Mn oxides from several productive sites located in eastern Tennessee and northern Virginia display morphologies that include botryoidal and branching forms, massive nodules, breccia matrix cements, and fracture fills. The primary ore minerals include hollandite, cryptomelane, and romanèchite. Samples of Mn oxides from multiple localities in these regions were analyzed using electron microscopy, X-ray analysis, Fourier transform infrared spectroscopy, and trace/rare earth element geochemistry. The samples from eastern Tennessee have biological morphologies, contain residual biopolymers, and exhibit REE signatures that suggest the ore formation was due to supergene enrichment (likely coupled with microbial activity). In contrast, several northern Virginia ores hosted within quartz-sandstone breccias exhibit petrographic relations, mineral morphologies, and REE signatures indicating inorganic precipitation, and a likely hydrothermal origin with supergene overprinting. Nodular accumulations of Mn oxides within weathered alluvial deposits that occur near to breccia-hosted Mn deposits in Virginia show geochemical signatures that are distinct from the breccia matrices, and appear to reflect remobilization of earlier-emplaced Mn and concentration within supergene traps. Based on the proximity of all of the productive ore deposits to mapped faults or other zones of deformation, we suggest that the primary source of all of the Mn may have been deep-seated, and that Mn oxides with supergene and/or biological characteristics result from the local remobilization and concentration of this primary Mn. Carmichael ABSTRACTManganese oxide deposits have long been observed in association with carbonates within the Appalachian Mountains, but their origin has remained enigmatic for well over a century. Ore deposits of Mn oxides from several productive sites located in eastern Tennessee and northern Virginia display morphologies that include botryoidal and branching forms, massive nodules, breccia matrix cements, and fracture fills. The primary ore minerals include hollandite, cryptomelane, and romanèchite. Samples of Mn oxides from multiple localities in these regions were analyzed using electron microscopy, X-ray analysis, Fourier transform infrared spectroscopy, and trace/rare earth element geochemistry. The samples from eastern Tennessee have biological morphologies, contain residual biopolymers, and exhibit REE signatures that suggest the ore formation was due to supergene enrichment (likely coupled with microbial activity). In contrast, several northern Virginia ores hosted within quartz-sandstone breccias exhibit petrographic relations, mineral morphologies, and REE signatures indicating inorganic precipitation, and a likely hydrothermal origin with supergene overprinting. Nodular accumulations of Mn oxides within weathered al...

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Mn- and Fe-rich black travertine shrubs; bacterially (and nanobacterially) induced precipitates

Cited by 84 publications

References 28 publications

Frutexites encrustations on rugose corals (Middle Devonian, southern Morocco): complex growth of microbial microstromatolites

Frutexites encrustations on rugose corals (Middle Devonian, southern Morocco): complex growth of microbial microstromatolites

Mineralogy and stable isotope geochemistry of the Ab Ask travertines in Damavand geothermal field, Northeast Tehran, Iran

New insight into the origin of manganese oxide ore deposits in the Appalachian Valley and Ridge of northeastern Tennessee and northern Virginia, USA

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