Hydrogen and oxygen isotope evidence for origin of MVT-forming brines, southern Appalachians

Kesler, Stephen E.; Vennemann, Torsten; Frederickson, Christian; Breithaupt, Angela; Vazquez, Rodrigo; Furman, Francis C.

doi:10.1016/s0016-7037(97)00014-8

Cited by 59 publications

(35 citation statements)

References 33 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…We also note that recently Kesler et al (1997) have interpreted similarly depleted 8D values (to -119%o) for MVT mineralizing brines in the southern Appalachian orogen to reflect interaction of the brines with organic matter in the wallrocks. 3.…”

Section: Sources Of the Vein-forming Fluidssupporting

confidence: 56%

Carboniferous barite-fluorite mineralization in the Late Devonian Kinsac Pluton, southern Nova Scotia

Kontak¹,

Horne

Ansdell

et al. 1999

atgeol

View full text Add to dashboard Cite

Abundant barite ± fluorite ± quartz veins occur along the eastern margin of the Late Devonian Kinsac Pluton, a peraluminous granite that intruded metasedimentary rocks of the Meguma Group. The barite veins, striking 120° with vertical dip, occur in areas of strongly fractured granite, but the veins are not deformed and may contain lenses of comminuted granite. The veins (< 0.6 m wide) are dominated by coarse, cloudy white barite euhedra with or without a late infill of euhedral clear quartz and pink to dark purple fluorite. 40Ar/39Ar step-wise heating of a K-feldspar megacryst in granite immediately adjacent to a barite vein indicates a 354 Ma plateau age for the high-temperature gas fraction and a ca. 320 Ma age for the lowtemperature gas fraction. The younger age is interpreted to record partial resetting of K-feldspar due to interaction of the mineral with vein-forming fluids.Fluid inclusions (aqueous, L-V types) hosted by vein fluorite have homogenization temperatures of 100° to 130°C. Last melting o f ice indicates salinities of 24 to 28 wt. % equivalent NaCl, but low eutectic temperatures indicate that the fluids are mixed NaCl-CaCl2-FeCl2-MgCl2 brines. Although fluorite-hosted fluid inclusions from the South Mountain Batholith have similar salinities, they homogenize at temperatures of 150° to 160°C. Stable isotopic studies of vein minerals indicate 834Sbarite = +13 ± 2%o, 5 l8Oquartz = +22%oand 8D for fluid inclusion extracts are -123 to -165 %o. The data are interpreted to indicate that: (1) sulphur was derived from dissolution of Windsor Group evaporites rather than from sulphides in basement rocks; (2) the 5 l8Owater of the veins was +8 to +12 %o for 100° to 150°C, which is consistent with either a basinal or metamorphic fluid; (3) the fluids interacted with organic matter to generate the low 8D values. Measured 87Sr/86Sr on barite (0.7120; n=2) and fluorite (0.7086) indicate that the fluids exchanged with a radiogenic source, either the Horton Group or the Meguma Group being the most likely reservoir.Collectively the data indicate vein formation during the Early Carboniferous, when the study area was buried under ca. 2-3 km of Carboniferous strata which have subsequently been eroded. Basinal-type fluids were focused into zones of extension which opened as a result of high Pfluld, in concert with sinistral movement on NW-trending faults that crosscut the Meguma Terrane.On trouve une abondance de filons de barytine ± fluorite ± quartz le long de la marge orientale du pluton du Devonien superieur de Kinsac, granite hyperalumineux qui s'est introduit dans des roches metasedimentaires du groupe de Meguma. Les filons de barytine, orientes selon un pendage vertical de 120°, se trouvent dans des zones de granite fortement fracturees, mais ils ne sont pas deformes et ils pourraient renfermer des lentilles de granite fragments. Les filons (< 0,6 m) sont domines par la presence de barytine automorphe blanc trouble, grossiere, avec ou sans remplissage tardif de quartz transparent automorphe et de fluorite rose a...

show abstract

Section: Sources Of the Vein-forming Fluidssupporting

confidence: 56%

Carboniferous barite-fluorite mineralization in the Late Devonian Kinsac Pluton, southern Nova Scotia

Kontak¹,

Horne

Ansdell

et al. 1999

atgeol

View full text Add to dashboard Cite

show abstract

“…Ions in the inclusion fluids are K + , Na + , Ca + , Mg 2+ , F -and Cl -. These natures of the ore fluids are similar to those of MVT deposits except for lower Br-contents (Kesler et al, 1995(Kesler et al, , 1996(Kesler et al, , 1997. The calculated δ 18 O H2O values of fluid inclusions of calcites from the Huize ore field are 7 to 11 per mil and the δD values range from -44 to -56 per mil.…”

Section: Hydrogen and Oxygenmentioning

confidence: 57%

Isotope geochemistry of the Huize Zn-Pb ore field, Yunnan Province, Southwestern China: Implication for the sources of ore fluid and metals

Huang

Yin

2007

Geochem. J.

View full text Add to dashboard Cite

The Huize ore field, which is the most famous high-grade Zn-Pb ore field in China, comprises the Kuangshanchang and Qilinchang deposits. The Zn and Pb reserves of these two deposits are more than 5 Mt with ore grades ranging from 25% to 35% in weight. Lead, sulfur, carbon, oxygen, hydrogen and strontium isotope geochemistry is reported to help understand the sources of the ore fluid and metals. Sr values may be due to the reaction between the ore fluid and the shale, clastic rocks and mudstone underlying the host rock or the fluid might have originated from these rocks.

show abstract

“…The coupling of Ba and Mn has been used to describe primary Mn oxide precipitation in a euxinic marine basin environment (Maynard, 2010), but recent reevaluations of the paleoenvironments of the host sediment sequences (the Shady/Tomstown Dolomite, Erwin/Antietam Sandstone, and Rome/Waynesboro Formation) do not find any evidence for early Paleozoic anoxic basins in the study areas (Hageman and Miller III, 2016;Smoot and Southworth, 2014). The source of the Ba is unclear, but Mississippi Valley Type (MVT) hydrothermal ore deposits containing barite are known throughout the Cambrian sediments of the central and southern Appalachains (Kesler et al, 1997 and references therein) and many of these locations either partially or completely overlap with the Mn oxide ore locations described throughout the cental Appalachians ( Figure 1). Therefore, while all samples are generally consistent with a supergene terrestrial fluid source, it is very possible that they represent multiple generations of dissolution and recrystallization of earlierformed hydrothermal Mn bearing minerals.…”

Section: Geochemical Associationsmentioning

confidence: 99%

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

View full text Add to dashboard Cite

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...

show abstract

Hydrogen and oxygen isotope evidence for origin of MVT-forming brines, southern Appalachians

Cited by 59 publications

References 33 publications

Carboniferous barite-fluorite mineralization in the Late Devonian Kinsac Pluton, southern Nova Scotia

Carboniferous barite-fluorite mineralization in the Late Devonian Kinsac Pluton, southern Nova Scotia

Isotope geochemistry of the Huize Zn-Pb ore field, Yunnan Province, Southwestern China: Implication for the sources of ore fluid and metals

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

Contact Info

Product

Resources

About