Geochemistry of metal-rich brines from central Mississippi Salt Dome basin, U.S.A.

Kharaka, Yousif K.; Maest, Ann S.; Carothers, William W.; Law, Leroy M.; Lamothe, Paul J.; Fries, T.L.

doi:10.1016/0883-2927(87)90008-4

Cited by 231 publications

(127 citation statements)

References 28 publications

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“…To understand the influence of the broad geological context of the formation water, the Carpenter and Miller, 1969Carpenter et al, 1974Carpenter, 1978Collins, 1969Collins, 1975Collins, 1987Conolly et al, 1990Crossey et al, 1986Edmunds et al, 1982Egeberg and Aargaard, 1989Ferguson et al, 1993Fisher and Boles, 1990Fisher and Kreitler, 1987Fontes and Matray, 1993h Hitchon et al, 1971Kharaka and Carothers, 1988Kharaka et al, 1986Kharaka et al, 1987Land and Macpherson, 1989Lundegard and Trevena, 1990Macpherson, 1992Merino, 1975Moldovanyi and Walter, 1992Morad et al, 1994Morton and Land, 1987Sanders, 1991Stueber and Walter, 1991Stueber et al, 1993Wilson and Long, 1993aWilson and Long, 1993b Klemme and Ulmishek (1991). The basin type and presence or absence of salt in the record have been taken from the publications or from regional geology publications.…”

Section: Introductionmentioning

confidence: 99%

Controls on halogen concentrations in sedimentary formation waters

Worden

1996

Mineral. mag.

108

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Chlorine is the most abundant halogen in sedimentary formation waters with concentrations from <100 to >250000 mg/1. Bromine is the second most abundant halogen at <1 mg/1 to >6000 rag/1 with iodine from <0.1 rag/1 to >100 mg/1 and fluorine from <0.1 rag/1 to 30 mg/L Chlorine and bromine show a strong systematic covariation suggesting that they are subject to the same controlling mechanisms. Fluorine only shows relatively high concentrations at elevated chlorine and bromine concentrations showing that fluorine, chlorine and bromine are possibly controlled by the same processes. Iodine does not correlate with any of the other halogens indicating that unique processes control iodine.Key geological parameters that influence chlorine and bromine (and possibly fluorine) concentrations are the presence of salt in a basin, the age of the reservoir unit and the kerogen-type within the main hydrocarbon source rock in a basin. The presence of salt in a basin shows that sea water was evaporated to halite saturation producing connate waters with high concentrations of chlorine and bromine. The presence of salt also leads to high salinity waters through water-salt interaction during burial and diagenesis. Tertiary reservoirs typically have much lower chlorine and bromine concentrations than Mesozoic or Palaeozoic reservoirs. The age of the reservoir unit may simply reflect the different amounts of time available for formation water to interact with salt. The dominance of type II marine kerogen in a basin leads to higher bromine concentrations. This may reflect the dominance of a marine influence in a basin which is more likely to lead to salt deposition than terrestrial depositional environments. Iodine concentrations are independent of all these parameters. Other geological parameters such as depth of burial, temperature, basin forming mechanism and reservoir lithology have no influence upon halogen concentrations.Key processes that affect halogen concentrations are sea water evaporation and dilution, water-salt interaction and input from organic sources. Chlorine and bromine data lie close to the experimentally-derived sea water evaporation trend showing that sea water evaporation may be an important general control on halogens. Sea water dilution is probably responsible for most low salinity formation water chlorine and bromine concentrations for the same reason. Sea water dilution can occur either by meteoric invasion during burial, or following uplift and erosion, or by diagenetic dehydration reactions. Water can interact with salt in a variety of ways: halite dissolution by congruent processes, halite recrystallization by incongruent processes, sylvite dissolution or recrystallization and halite fluid inclusion rupture. Halite dissolution will lead to high chlorine and relatively low bromine waters because halite contains little bromine. In contrast, halite recrystallization will lead to bromine-enhanced waters because NaBr dissolves preferentially to NaC1. The occurrence of dissolution or recrystallization wil...

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Section: Introductionmentioning

confidence: 99%

Controls on halogen concentrations in sedimentary formation waters

Worden

1996

Mineral. mag.

108

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“…The bestdocumented metal-rich brines from the standpoint of their trace-metal content are the Na-Ca-Cl oil field brines hosted by Jurassic and Cretaceous formations in central Mississippi, USA. These waters have total dissolved solids contents up to 350000 mg/l, density locally exceeding 1.2 g/ml, and contain up to several hundred mg/l Pb + Zn (Carpenter et al 1974;Kharaka et al 1987). Reservoir temperatures for these brines range from 90-130°C, and salinity and metal content generally correspond to increasing temperature and depth.…”

Section: Geochemistry Of Metal-rich Formation Watersmentioning

confidence: 98%

“…However, some of the deeper host units, such as the Jurassic Smackover Formation, contain significant amounts of H2S, which results in low base metal contents. Thermochemical modelling by Kharaka et al (1987) indicates that both the sulphide-rich (low metals) brines and the Zn-Pb-rich (sulphide-depleted) brines are approximately saturated with respect to sphalerite and galena.…”

Section: Geochemistry Of Metal-rich Formation Watersmentioning

confidence: 98%

Lithogeochemical Investigations Applied to Exploration for Sediment-Hosted Lead-Zinc Deposits

Lavery¹,

Leach

Saunders

1994

Sediment-Hosted Zn-Pb Ores

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Sediment-hosted stratiform massive sulphide (Sedex) deposits and Mississippi Valley-type (MVT) deposits differ in morphology, but there is considerable overlap in their host rock lithology, regional setting, size, grade, metal ratios, age of host rocks, lead isotopes, sulphur isotopes, and genesis. Recent advances in the understanding of basin-derived formation fluids provide a framework for interpreting the lithogeochemical signatures of these deposits. The composition of the ore fluids for both types of deposits is controlled in part by fluid-rock reactions within sedimentary basins, but the nature of the sediments in the basins, the source of the fluids, the thermal gradient in the basin, the migratory history of the fluids, and the physical and chemical conditions in the deposition al environment cause variations in the lithogeochemical patterns present. Studies of modern sedimentary formation waters indicate that diagenetic fluid-rock reactions in basins can liberate and dissolve significant amounts of metals. The most metal-enriched formation waters are brines with more than 200000 ppm total dissolved solids. Some brines contain more than several hundred ppm combined Fe, Zn, Pb, and Ba, and minor amounts of Cu, Ag, Mn, Cd, As, Sb, Ni, Co, Mo, and Tl.Copper, Ag, As, Sb and Ba are reported in more than 60% of the Sedex deposits studied; Mn, Cd, Ni, Co, Au, Hg, Bi, B, Sn, Mo, F, Tl, Ge and Sr are reported in more than 20%; and V, Ga, In, Se, Cr and NH4 + are reported in more than 10% of the deposits. Geochemical variables which have received some exploration attention and which show promise as guides to Sedex deposits include: Tl, F, NH4 +, Hg, Pt, Pd, Zr, Cl-bearing minerals, rare earth elements, stable isotopes, and carbonaceous material.MVT districts were formed by ore-forming fluids which affected large volumes of the cmst. Widespread and isolated geochemical anomalies are, therefore, to be expected. Although there is a great diversity in deposit characteristics, it is possible to establish exploration criteria for additional deposits within a district or region. Geochemical analysis of insoluble residues has been used to define geochemical patterns that coincide with known ore trends and with ore-related geological features in the Southeast Missouri districts. Studies of rock alteration or identification of minerals precipitated from the brines can provide evidence of pathways used by the ore fluids. Hydrothermal dolomitization is the most important type of alteration; silicification is associated with ore in so me districts, and alteration of feldspars near ore has been identified in the Southeast Missouri lead district. Organic geochemistry and fluid inclusion studies are in progress and may yield practical exploration guides to MVT deposits.The presence of Cu, Mo, Pb, Zn, Ni, Co, Ag, Sb, As, Cd, and Ba in oil field brines/well scales, in MVT deposits, and in Sedex deposits lends credence to the use of these elements in lithogeochemical surveys. Many of the element associations described are bas...

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“…These include 'anomalously' Pb-rich solutions in fluid inclusions hosted by sphalerite in Mississippi Valley-type (MVT) and Irish Pb-Zn deposits, which contrast with relatively metal-poor fluids in associated gangue minerals of the same deposits (Stoffell et al, 2008;). Similar to some recent basin brines (Kharaka et al, 1987), these ore-forming fluids must be sulfide-deficient, either due to sulfate predominance under unusually oxidizing conditions at their source (Fig. 4) or as a result of a distinct chemical evolution path experienced during cooling from higher temperatures.…”

Section: Fig 4: Ph-redox Diagram Of the H2o-fe-s-o-h-(-mentioning

confidence: 99%