Radiocarbon studies of recent dolomite from Deep Spring Lake, California

Peterson, M. N. A.; Bien, G. S.; Berner, Robert A.

doi:10.1029/jz068i024p06493

Cited by 123 publications

(49 citation statements)

References 8 publications

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“…(2009) to form during whitings in the little Bahama Bank suggesting that re‐suspended dolomite grains provide nuclei for ongoing precipitation. In addition, zoned crystals were observed in Deep Springs Lake – as shown by leaching experiments (Peterson et al. , 1963; Clayton et al.…”

Section: Discussionmentioning

confidence: 81%

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Calcium and magnesium‐limited dolomite precipitation at Deep Springs Lake, California

Meister¹,

Reyes

Beaumont

et al. 2011

Sedimentology

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Dolomite [Ca,Mg(CO3)2] precipitation from supersaturated ionic solutions at Earth surface temperatures is considered kinetically inhibited because of the difficulties experienced in experimentally reproducing such a process. Nevertheless, recent dolomite is observed to form in hypersaline and alkaline environments. Such recent dolomite precipitation is commonly attributed to microbial mediation because dolomite has been demonstrated to form in vitro in microbial cultures. The mechanism of microbially mediated dolomite precipitation is, however, poorly understood and it remains unclear what role microbial mediation plays in natural environments. In the study presented here, simple geochemical methods were used to assess the limitations and controls of dolomite formation in Deep Springs Lake, a highly alkaline playa lake in eastern California showing ongoing dolomite authigenesis. The sediments of Deep Springs Lake consist of unlithified, clay‐fraction dolomite ooze. Based on δ18O equilibria and textural observations, dolomite precipitates from oxygenated and agitated surface brine. The Na‐SO4‐dominated brine contains up to 500 mm dissolved inorganic carbon whereas Mg2+ and Ca2+ concentrations are ca 1 and 0·3 mm, respectively. Precipitation in the subsurface probably is not significant because of the lack of Ca2+ (below 0·01 mm). Under such highly alkaline conditions, the effect of microbial metabolism on supersaturation by pH and alkalinity increase is negligible. A putative microbial effect could, however, support dolomite nucleation or support crystal growth by overcoming a kinetic barrier. An essential limitation on crystal growth rates imposed by the low Ca2+ and Mg2+ concentrations could favour the thermodynamically more stable carbonate phase (which is dolomite) to precipitate. This mode of unlithified dolomite ooze formation showing δ13C values near to equilibrium with atmospheric CO2 (ca 3‰) contrasts the formation of isotopically light (organically derived), hard‐lithified dolomite layers in the subsurface of some less alkaline environments. Inferred physicochemical controls on dolomite formation under highly alkaline conditions observed in Deep Springs Lake may shed light on conditions that favoured extensive dolomite formation in alkaline Precambrian oceans, as opposed to modern oceans where dolomites only form diagenetically in organic C‐rich sediments.

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Section: Discussionmentioning

confidence: 81%

“…In this study, a simple geochemical approach was used to constrain the physicochemical limitations of dolomite formation in Deep Springs Lake, a highly alkaline playa lake in Eastern California (Fig. 1), where recent dolomite forms as fine‐grained unlithified ooze (Jones, 1961, 1965; Peterson et al. , 1963, 1966; Clayton et al.…”

Section: Introductionmentioning

confidence: 99%

Calcium and magnesium‐limited dolomite precipitation at Deep Springs Lake, California

Meister¹,

Reyes

Beaumont

et al. 2011

Sedimentology

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“…If the dolomite in Lake Tecopa was precipitated at the same rate as that described by Peterson, Bien, and Berner (1963) in Deep Spring Lake, the size of the largest dolomite crystals based on the age of the lake should be approximately 0.1 micrometers. At least some of the dolomite was found in the sand-and silt-sized fractions, which indicates that perhaps some of the dolomite in Lake Tecopa is detrital, or was formed by the magnesium replacement of calcium in some of the calcite.…”

Section: Carbonatesmentioning

confidence: 90%

“…Jones (1961), on the basis of the pattern of distribu tion of the dolomite in the Deep Spring Lake playa in California, attributed the formation of the dolomite to direct precipitation from solutions. Peterson, Bien, and Berner (1963) concluded from radiocarbon dating studies that the dolomite in Deep Spring Lake was precipitated directly from solution with no in termediate calcite phase. They stated that very slow crystal growth (on the order of hundreds of Angstroms per thousand years) seems necessary to form dolomite.…”

Section: Carbonatesmentioning

confidence: 99%

Clay mineralogy of Pleistocene Lake Tecopa, Inyo County, California

Starkey¹,

Blackmon²

1979

Professional Paper

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“…Petersen et al, 1963;Von der Borch, 1976;Garcia del Cura et al, 2001), saline-evaporitic (e.g. Primary dolomite has been recognized in various settings, including lacustrine (e.g.…”

Section: Introductionmentioning

confidence: 99%

Geomorphic and hydrological controls on groundwater dolocrete formation in the semi‐arid Hamersley Basin, northwest Australia

Mather

Nash

Dogramaci

et al. 2019

Earth Surf Processes Landf

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Groundwater dolocretes may exert an important geomorphic control on landscape evolution within sub‐humid to arid regions. However, the geomorphic and hydrogeological settings of dolocrete remain poorly described. The hydrochemical conditions of dolomite precipitation in groundwater environments are also not well known. Classic models of dolocrete formation explain dolomite precipitation from highly evolved groundwaters at the terminus of major drainage but do not explain dolocrete distributed in regionally elevated landscapes, upgradient of major drainage. This study investigated the mineralogy, micromorphology and stable carbon and oxygen isotope compositions of three dolocrete profiles within a regionally elevated sub‐basin of the Hamersley Ranges in the Pilbara region of northwest Australia. We sought to establish the environmental and hydrochemical conditions and present a model for dolocrete formation. We found that dolocrete formed within zones of emerging groundwater under saline‐evaporitic conditions within internally draining sub‐basins, most likely during the Late Miocene and Pliocene. Saline‐evaporitic conditions were indicated by: (i) the mineralogy, dominated by dolomite, palygorskite and smectite; (ii) desiccation features and the presence of phreatic and vadose cements, indicative of a shallow fluctuating water table, and; (iii) dolomite δ18O values (median = –5.88 ‰). Dolomite precipitation was promoted by evaporation and carbon dioxide degassing from shallow magnesium (Mg)‐rich groundwater. These factors appear to have been the major drivers of dolocrete development without a requirement for significant down‐dip hydrochemical modification. Primary dolomite precipitation was possible due to the presence of microbial extracellular polymeric substances (EPS). EPS provided negatively charged nucleation sites, which bound Mg2+, overcoming kinetic effects. High microbial activity within groundwater systems suggest these processes may be important for dolocrete formation worldwide and that groundwater dolocretes may be more pervasive in landscapes than currently recognized. © 2019 John Wiley & Sons, Ltd. © 2019 John Wiley & Sons, Ltd.

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Radiocarbon studies of recent dolomite from Deep Spring Lake, California

Cited by 123 publications

References 8 publications

Calcium and magnesium‐limited dolomite precipitation at Deep Springs Lake, California

Calcium and magnesium‐limited dolomite precipitation at Deep Springs Lake, California

Clay mineralogy of Pleistocene Lake Tecopa, Inyo County, California

Geomorphic and hydrological controls on groundwater dolocrete formation in the semi‐arid Hamersley Basin, northwest Australia

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