Smackover Formation brines (southwest Arkansas)
Arkansas, southwest shelf (Gulf Coast basin), United States
OtherBr, Li (saumures)
- Type
- Formation brines of oolitic carbonate reservoirs
Highly saline brines (up to 365 g/L dissolved solids) of Upper Smackover oolitic reservoirs (Upper Jurassic), at 1300 to 3250 m and 60 to 105 °C, very rich in bromine and alkali metals; an E-W H2S-rich belt, near the South Arkansas fault system, concentrates B, Li, K, Rb and the most radiogenic Sr. See also the East Texas Smackover brines entry. Moldovanyi et al. (1993): δ11B from +27 to +50 ‰ and 87Sr/86Sr from 0.70743 to 0.71071, mixing with deep siliciclastic diagenetic waters.
δ11B in ‰ (per mil) Values of the same system
Standard : NIST SRM 951
| Value | Range | n | Mineral or matrix | Source |
|---|---|---|---|---|
| 35 ± 6 ‰ | 27 / 41 ‰ | 8 | brine of the H2S-rich belt Mean and standard deviation recalculated from 8 analyses, +27 to +41 (#1 +41; #4 +27; #6 +31; #9 +27; #10 +39; #17 +33; #31 +38; #41 +41). Boron contents 56 to 358 mg/L. For all brines, the abstract gives +26 to +50 ‰ and the text +26 to +51 ‰, whereas Table 1 ranges from +27 to +50 ‰. | Moldovanyi et al. (1993), Strontium, boron, oxygen, and hydrogen isotope geochemistry of … |
| 44 ± 5 ‰ | 34 / 50 ‰ | 9 | H2S-free brine of oolitic reservoirs (northwestern, northern, eastern and southern areas) Mean and standard deviation recalculated from 9 analyses, +34 to +50 (#46 +43; #51 +41; #53 +46; #55 +50; #57 +42; #67 +50; #75 +45; #78 +47; #88 +34). Boron contents 35 to 142 mg/L; northern brines (#67 to #75), diluted by meteoric water along faults reaching the surface, have the lowest δ18O and δD. | Moldovanyi et al. (1993), Strontium, boron, oxygen, and hydrogen isotope geochemistry of … |
| 40 ‰ | 1 | brine of siliciclastic facies (#43 East Texas, #44 western Arkansas) Single analysis (#43). Sandstone and red-bed reservoir derived from a nearby intrusion, excluded from the means by the authors. | Moldovanyi et al. (1993), Strontium, boron, oxygen, and hydrogen isotope geochemistry of … |
87Sr/86Sr isotope ratio, no unit Values of the same system
Standard : NIST SRM 987
| Value | Range | n | Mineral or matrix | Source |
|---|---|---|---|---|
| 0.70898 ± 0.00088 | 0.70743 / 0.71048 | 25 | brine of the H2S-rich belt Mean and standard deviation recalculated from 25 analyses, 0.70743 to 0.71048 (#1 0.70916; #4 0.71048; #6 0.70997; #7 0.70974; #8 0.70964; #9 0.71015; #10 0.70824; #11 0.70875; #14 0.70967; #15 0.70981; #16 0.70816; #17 0.70977; #19 0.70962; #22 0.70765; #23 0.70875; #24 0.70774; #25 0.70908; #26 0.70906; #31 0.70884; #34 0.70839; #35 0.70809; #37 0.70933; #39 0.70935; #41 0.70743; #42 0.70754). Published mean 0.70898 ± 0.00088. | Moldovanyi et al. (1993), Strontium, boron, oxygen, and hydrogen isotope geochemistry of … |
| 0.70863 ± 0.0006 | 0.7078 / 0.71011 | 22 | H2S-free brine of oolitic reservoirs (northwestern, northern, eastern and southern areas) Mean and standard deviation recalculated from 22 analyses, 0.70780 to 0.71011 (#46 0.70828; #47 0.70907; #51 0.70886; #53 0.70994; #55 0.71011; #58 0.70834; #60 0.70874; #62 0.70814; #64 0.70780; #65 0.70791; #67 0.70859; #70 0.70855; #75 0.70786; #78 0.70935; #79 0.70869; #81 0.70801; #83 0.70886; #84 0.70833; #85 0.70852; #86 0.70873; #87 0.70867; #88 0.70843). Published mean 0.70863 ± 0.00060, without siliciclastic brines #43 and #44. | Moldovanyi et al. (1993), Strontium, boron, oxygen, and hydrogen isotope geochemistry of … |
| 0.71058 ± 0.00019 | 0.71044 / 0.71071 | 2 | brine of siliciclastic facies (#43 East Texas, #44 western Arkansas) Mean and standard deviation recalculated from 2 analyses, 0.71044 to 0.71071 (#43 0.71044; #44 0.71071). Most radiogenic Sr of the dataset. | Moldovanyi et al. (1993), Strontium, boron, oxygen, and hydrogen isotope geochemistry of … |
δ18O in ‰ (per mil) Values of the same system
Standard : V-SMOW
| Value | Range | n | Mineral or matrix | Source |
|---|---|---|---|---|
| 6 ± 0.9 ‰ | 3.7 / 7.1 ‰ | 12 | brine of the H2S-rich belt Mean and standard deviation recalculated from 12 analyses, +3.7 to +7.1 (#1 +6.4; #6 +7.1; #9 +6.1; #17 +6.9; #19 +6.0; #22 +6.5; #25 +5.9; #31 +6.2; #35 +5.8; #39 +6.1; #41 +5.6; #42 +3.7). | Moldovanyi et al. (1993), Strontium, boron, oxygen, and hydrogen isotope geochemistry of … |
| 4.4 ± 2.1 ‰ | 0.2 / 7.4 ‰ | 15 | H2S-free brine of oolitic reservoirs (northwestern, northern, eastern and southern areas) Mean and standard deviation recalculated from 15 analyses, +0.2 to +7.4 (#46 +4.4; #47 +5.3; #51 +4.6; #53 +2.9; #55 +6.0; #58 +5.5; #67 +0.2; #70 +0.4; #73 +3.7; #75 +2.8; #78 +4.4; #79 +5.7; #83 +6.2; #86 +5.9; #88 +7.4). | Moldovanyi et al. (1993), Strontium, boron, oxygen, and hydrogen isotope geochemistry of … |
δD in ‰ (per mil) Values of the same system
Standard : V-SMOW
| Value | Range | n | Mineral or matrix | Source |
|---|---|---|---|---|
| −13 ± 4 ‰ | −22 / −6 ‰ | 12 | brine of the H2S-rich belt Mean and standard deviation recalculated from 12 analyses, -22 to -6 (#1 -11; #6 -9; #9 -6; #17 -13; #19 -10; #22 -17; #25 -9; #31 -13; #35 -13; #39 -18; #41 -15; #42 -22). | Moldovanyi et al. (1993), Strontium, boron, oxygen, and hydrogen isotope geochemistry of … |
| −16 ± 5 ‰ | −26 / −9 ‰ | 15 | H2S-free brine of oolitic reservoirs (northwestern, northern, eastern and southern areas) Mean and standard deviation recalculated from 15 analyses, -26 to -9 (#46 -13; #47 -14; #51 -12; #53 -10; #55 -10; #58 -9; #67 -19; #70 -25; #73 -26; #75 -22; #78 -18; #79 -12; #83 -17; #86 -18; #88 -15). | Moldovanyi et al. (1993), Strontium, boron, oxygen, and hydrogen isotope geochemistry of … |
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Cite this page
IsoFind Atlas (2026). Smackover Formation brines (southwest Arkansas), isotope signatures. https://www.isofind.tech/isotopes/en/deposits/saumures-de-la-formation-de-smackover-sud-ouest-de-l-arkansas/ (accessed 2026-10-20).
@misc{isofind2026smackoverformationbrinessouth,
title = {Smackover Formation brines (southwest Arkansas), isotope signatures},
author = {{IsoFind Atlas}},
year = {2026},
url = {https://www.isofind.tech/isotopes/en/deposits/saumures-de-la-formation-de-smackover-sud-ouest-de-l-arkansas/},
note = {Accessed 2026-10-20}
}Updated : 2026-10-20