Edwards limestone

Misak, M.D., et al. "Edwards Limestone Completions Improved by New Stimulation Technique," SPE paper 7115, 1978 Southwest Texas Regional SPE Meeting, Corpus Christi, April 14. 

Cowart, J. B., Osmond, J. K., Oxidation/reduction in the Edwards Limestone aquifer as indicated by dissolved uranium isotopes, Geol. Soc. America, Abstracts with Programs, 9(7), 938 (1977). 

The Pleistocene terra rossa of central Texas is a soil that developed during times of tropical weathering between 0.7 and 2.0 m.y.b.p. Today it is found almost exclusively as an uncommon cave fill in the Edwards Limestone (Young, 1986). Analysis of the XRD pattern of the terra rossa indicates that it is composed of interstratified kaolinite/smectite and is clearly not the source for the BS I/S (Fig. 5). 

Most caves in the Edwards Limestone do contain a clay suite very similar to the clays found in the suspended sediment discharged from Barton Springs. The I/S in the cave clays is identical to the BS I/S (Fig. 5). The presence of laminations in some cave clay deposits indicates that, like the terra rossa, the clastic material was washed into caves and was not derived from dissolution of the Edwards Limestone (Kastning, 1986 Ellis, 1986 Flavorka et ak, 1996). Similarity of clay suites in the caves and in the discharged sediment implies that the source area for the clays, and the processes leading to its deposition in caves or transport through the aquifer, have been the same for an extended period of time. 

Figure 5. XRD patterns of the <2 pm fraction (oriented and glycol solvated) of Edwards Limestone autochthonous clay samples. K/S = kaolinite/smectite, other peak labels as in Figure 4.

Pearson, Jr., F.J. and Rettman, P.L., 1976. Geochemical and isotopic analyses of waters associated with the Edwards limestone aquifer, central Texas. U.S. Geol. Surv., Rep. Edwards Undergr. Water Dist., 35 pp. 

Sweden and Madagascar where it occurs in the crystalline limestones in huge crystals, In the United States it occurs in New York State at Edwards, Hammond, DeKalh, Monroe and, in New Jersey, at Franklin Tn Canada it is found at many places in Ontario and Quebec. 

Wastes from lead-rich mineral deposits typically form anglesite in sulfate-dominant environments, but in limestone-dominated host rocks and in gangue containing abundant carbonates, both cerussite [PbCOs] and hydrocerussite [Pb3(-003)2(01-1)2] have been reported as secondary minerals in mining-related wastes. Several carbonate and hydroxycarbonate minerals of copper and zinc were reported by Hudson-Edwards et al. (1996) as secondary products in stream sediments in the Tyne Basin, England. 

The I/S peak at 11.8 A in the pattern of soil developed on the Del Rio Clay indicates ordered interstratification as opposed to the random interstratification in the BS I/S (16.9 A peak). Soils developed on the Buda Limestone contain smectite and yield XRD patterns similar to Edwards soil A. Therefore, neither the Del Rio Clay nor the Buda Limestone is the source of the Barton Springs suspended sediment. 

Longman, M.W. and Mench, P.A., 1978. Diagenesis of Cretaceous limestones in the Edwards aquifer system of south-central Texas A scanning electron microscope study. Sediment. Geol., 21 241—276. 

Fort Riley Limestone FRL and Lenders Limestone LL possess micro- and mesopores in amounts comparable to Berea sandstones with permeabilities in the range of 47 - 182 md. However the limestone permeabilities are only about 2 md. Overall, the Edwards (GC) EGC serves as a useful model rock for study of oil recovery because it has moderate permeability and porosity and complications related to the presence of microporosity are minimal. 

The Edwards (GC) limestone has the lowest fraction of microporosity and is especially suited as a model limestone for oil recovery studies. 

On the basis of the Scholtz Station test results, Rush and Edwards (1977) concluded that the overall performance of a properly designed and operated double alkali system should be superior to that of direct limestone and lime systems because... 

Ormerod, S.J. Edwards, R.W. (1985) Stream acidity in some areas of Wales in relation to historical trends in afforestation and the usage of agricultural limestone. J, Environ, Management 20,189-197. 

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