Construction of the seawater curve for the cenozoic and cretaceous: Supporting data

Koepnick, Richard B.; Burke, W. H.; Denison, Rodger E.; Hetherington, E.A.; Nelson, H F; Otto, J.B.; Waite, Lowell

doi:10.1016/0168-9622(85)90027-2

Cited by 229 publications

(60 citation statements)

References 23 publications

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“…a IS-S1 latitude and longitude coordinates are 30.61005°N and 97.68947°W. 1011 Central Texas vadose dripwater geochemistry carbonate rocks discussed in the text are from Koepnick et al (1985) and Oetting (1995) and have been adjusted to a value for NIST-SRM 987 of 0.710264.…”

Section: Methods and Resultsmentioning

confidence: 99%

“…Strontium isotope variations in regional Edwards aquifer system components. Histogram in the upper portion of the diagram represents twenty whole rock 87 Sr/ 86 Sr values determined for Lower Cretaceous carbonates and evaporites (18 from Koepnick et al, 1985, and2 from Oetting, 1995). In the lower portion of the diagram are 87 Sr/ 86 Sr variations measured in different aquifer components.…”

Section: Strontium Isotope Variationsmentioning

confidence: 99%

See 1 more Smart Citation

Controls on the spatial and temporal variability of vadose dripwater geochemistry: Edwards aquifer, central Texas

Musgrove

Banner

2004

Geochimica et Cosmochimica Acta

161

106

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Section: Methods and Resultsmentioning

confidence: 99%

Section: Strontium Isotope Variationsmentioning

confidence: 99%

Controls on the spatial and temporal variability of vadose dripwater geochemistry: Edwards aquifer, central Texas

Musgrove

Banner

2004

Geochimica et Cosmochimica Acta

161

106

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“…Stein et al (2000) indirectly checked the age of the evaporites by comparing their 87 Sr/ 86 Sr and 34 S/ 32 S isotope ratios to the corresponding (Pliocene) secular seawater values. The d 34 S values found (&20%) are in concert with Pliocene seawater, but the 87 Sr/ 86 Sr ratios in all the analyzed samples are below 0.709, the value of Pliocene ocean (Koepnic et al 1985). Moreover, they unveiled an unexpected difference in being systematically lower in gypsum, anhydrite, dolomite, and limestone (0.7082-0.7084) than in adjacent halite layers (0.7083-0.7087) within the same formation (Fig.…”

Section: The Lagoon Stagementioning

confidence: 71%

Geochemical History of the Dead Sea

Katz

Starinsky

2008

Aquat Geochem

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A Southward view of the Dead Sea western coast. The steep western escarpment of the Dead Sea basin, composed mainly of Upper Cretaceous limestone and dolomite, can be seen on the right. Beach terraces left by the shrinking lake run parallel to the shore. The larger part of the area between the present water line and the mountains was still under Dead Sea water just 50-60 years ago. The current fall of the lake's stand is around 1 m year -1 . Three on-shore sinkholes can be seen in the front of the photo, as well as two submerged ones near its lower left corner. These were caused by dissolution of a Holocene salt layer located tens of meters below the surface, resulting in the collapse of the overlying sediments. The retreat of the Dead Sea in recent years was followed by eastward migration of the freshwater-brine interface. This in turn brought diluted groundwater in contact with the subsurface salt layer, triggering its dissolution, and is considered as the culprit of the spreading phenomenon. Many sinkholes contain brine that was left over by the receding Dead Sea and was trapped within the surrounding sediments. Once inside a sinkhole, these brines evolve chemically by evaporation to various degrees. The difference in color between the brine in the onshore sinkholes reflects salinity-related differences in their biology.Abstract The evolution of the Dead Sea basin (DSB) brines from their birth in a Pliocene lagoon to their accommodation in the Dead Sea is described and discussed. The history of the brines is divided into two periods, corresponding to the successive depositional environments that prevailed in the DSB, namely a marine lagoon and an inland saline lake. Ancient Mediterranean seawater, supplied into the DSB lagoon through an inland channel from the north, was concentrated by evaporation into the halite field. The resulting Mg-enriched solution dolomitized surrounding, upper Cretaceous limestone, losing most of its Mg 2? to the limestone in exchange for Ca 2? . Cretaceous marine Sr 2? , concurrently released from the limestone into the brine, lowered its (Pliocene time) 87 Sr/ 86 Sr ratios. Consequently, a Ca-chloridic solution with lowered 87 Sr/ 86 Sr ratios was formed. Frequently changing conditions along the active Dead Sea rift enabled back-flow of the Ca-chloridic brines to the DSB, where they mixed with fresh seawater, unloading into the mixture their limestone-Sr. This process is reflected by the 87 Sr/ 86 Sr ratios (0.7082-0.7087) in the lagoon's gypsum, dolomite, aragonite, and halite, which is intermediate between that of Pliocene seawater (0.709) and that in the upper Cretaceous limestone (0.7074-0.7077). Disconnection of the lagoon from the ancient Mediterranean brought about its end, and opened the (ongoing) lacustrine chapter of the DSB, without interrupting the reflux of Ca-chloride brine back into the basin. By that time, the chloridic brines processed by the lagoon became locked in a large, almost closed system reservoir in the DSB and vicinity. We propose that a Ca-chloridic la...

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“…Most of these studies have focused on the more recent past, particularly the Cenozoic (DePaolo and Ingram, 1985;Koepnick et al, 1985;Palmer and Elderfield, 1985;Clemens et al, 1993;Sugarman et al, 1997;Martin et al, 1999). However, over the past decade many studies have looked in particular at the Cretaceous period (McArthur et al, 1992(McArthur et al, , 1993(McArthur et al, , 1994McLaughlin et al, 1995;Jenkyns et al, 1995;Bralower et al, 1997;Crame et al, 1999), which has been made possible with the recovery of wellpreserved carbonate and microfossils from ODP cores.…”

Section: Introductionmentioning

confidence: 97%