Halite deposition

Naturally occurring salt is known as halite. Halite is what s left when seas evaporate. Michigan, for instance, was underwater several times hundreds of miiiions of years ago. When the seas disappeared, huge deposits of halite were ieft. At one time or another, seas covered aii of the pianet, so halite deposits can be found aimost anywhere. 

Ideas about variations in sodium ion (Na+) and chloride ion (Cl ) concentrations are based on ancient halite inventories. The total volume of known halite deposits amounts to about 30% of the NaCI content of the present oceans. If all of this salt were added to the present oceans, the salinity of seawater would increase by about 30%, setting an upper limit. However, the ages of major halite deposits are reasonably well dispersed through geological time, suggesting that there was never a time when all of these ions were dissolved in seawater. 

Figure 10. Maximum homogcni/alion temperatures of lluid inclusions in halite (Th ,ax) versus depth from the top 90 m of the Death Valley core (lOOka-Oka, with uranium series dates shown on left) The plot represents a total of 2,328 homogenization temperature measurements Lacustrine halites, deposited in a perennial saline lake. 35 ka to 10 ka. have exceptionally low maximum homogenization temperatures which suggests brine temperatures 4°C to 15 °C below modern late April temperatures (From Lowenstein el al.. 1998. Fig. 8. p. 2.W).

Limiting Halite Deposition In a Wet High-Temperature Gas Well... 

Limiting halite deposition in a wet high-temperature gas well. There are several fields in the Netherlands that produce hydrocarbon gas associated with very high TDS connate waters. Classical oilfield scale problems (e.g., calcium carbonate, barium sulfate, and calcium sulfate) are minimal in these fields. Halite (NaCl), however, can be precipitated to such an extent that production is lost in hours. As a result, a bottom-hole fluid sample is retrieved from all new wells. Unstable components are fixed immediately after sampling, and pH is determined inider pressure. A full ionic and physical analysis is also carried out in the laboratory. 

Several examples of the dolomitization brines that have been formed from these end liquors are listed in Tables 2.2 and 2.3. In some areas, such as the Michigan (Figs. 2.2-2.4) and Paradox Basins (Fig. 2.5) in the United States, most of this brine appears to still be very near the potash/halite deposits, while in others its former presence is well documented (e.g., in Saskatchewan Fig. 2.6 Table 2.3) but much of it has migrated some distance away or has escaped. 

For the more concentrated calcium chloride brines associated with potash or late-stage halite deposits, there is also usually a very direct correlation between dolomite formations and the calcium chloride brine. An example of this is with... 

It is also not uncommon for the dolomitization brine to have been forced into porous formations in or above the potash or halite deposits, as indicated by... 

Even though most of the world s many potash deposits, as well as some of the even more common halite deposits, have formed dolomitization brine, in... 

The former Russian states have a large number of potash and halite deposits (Fig. 2.9), and calcium chloride brines have been associated with many of them. Sturua (1974) has presented a map of various Russian calcium chloride groundwater occurrences, and the majority of them are closely grouped near major potash deposits. In the Caspian Depression, Moskovskiy and Anisimov (1991) have reported such brines, and the Carpathian group s Stebnik potash deposit in south-central Russia (which contains potassium sulfate minerals, and not the normal sylvinite), still has dolomitization brine near the deposit (Valyashko et al, 1973). Similar brines have been found with 80-169 g/liter Ca in the Ukraine s Dnieper-Donets Basin, grading to 50, then 6 and finally 1.5 g/liter CaCl2 as the... 

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