Lakes closed basin

At Mono Lake, a closed basin, alkaline, saline lake in California, the concentrations of plutonium in the water column are about two orders of magnitude higher than in Lake Michigan(12). 

Figure 19. Plot of Li isotopic composition vs. inverse Li concentration for lakes and basinal/oilfield brines. Lakes open circle = major global lakes (Chan and Edmond 1988 Falkner et al. 1997) semi-open circle = western U.S. closed basin lakes (Tomascak et al. 2003). Oilfield brines inverted triangle = Williston basin, Saskatchewan (Bottomley et al. 2003) diamond = Israeli oilfields (Chan et al. 2002d). Mine waters (Canadian Shield basinal brines) square = Yellowknife, NWT (Bottomley et al. 1999) triangle = Sudbury, Ontario, area (Bottomley et al. 2003) star = Thompson, Manitoba, area (Bottomley et al. 2003). Average composition of seawater is included for reference.

Liebscher A, Barnes J, Sharp Z (2006) Chlorine isotope vapor-liquid fractionation during experimental fluid-phase separation at 400°C/23 Mpa to 450°C/42Mpa, Chem Geol 234 340-345 Lister GS, Kelts K, Chen KZ, Yu JQ, Niessen P (1991) Lake Qinghai, China closed-basin lake levels and the oxygen isotope record for ostracoda since the latest Pleistocene. Palaeogeogr PalaeocUmatol Palaeoecol 84 141-162... 

Although sepiolite-palygorskite occur frequently in closed basin, evaporite or lake deposits, these minerals are also known in Tertiary and late Paleozoic deep sea, shelf and shallow sea deposits. They have also been reported with persistent frequence by French clay mineralogists in Mesozoic and Tertiary saline and carbonate deposits (Millot, 1964). 

In closed basins (lakes, estuaries), the long-term dynamics of the vertical temperature distribution provides such a tool (Fig. 22.6). Let us assume that in a lake the... 

Measurements of 14C have rarely been used as tracers to study sources of individual DOC fractions. Aiken et al. (1996) used 14C measurements of fulvic acid in a permanently ice-covered closed basin lake in Antarctica to investigate sources of DOC in the lake. Sampling along a depth profile in the lake showed that the fraction of modern carbon decreased with depth and confirmed that the high concentrations of fulvic acid in the bottom waters represented an old source, with an age of around 3000 years, which was diffusing into the upper water column (Fig. 3). 

Fig. 9.4 Isotopic data of about 400 samples of rivers, lakes, and precipitation from various parts of the world. The best-lit line was termed the meteoric line. Its equation, as found by Craig (1961a), is dD = 8<5lsO + 10. The data in the encircled zone of closed basins is for East African lakes with intensive evaporation.

The conditions needed for formation of corderoite required by our estimated AG (Figure 7) are incompatible with any realistic natural environment. A combination of low pH and mildly reducing conditions with a high ratio of chloride to sulfide or sulfate is conceivable in the anaerobic sediments of closed-basin lakes, but the lowest pH would be closer to 4 than to 2.5. The AG of... 

Figure 1 Global distribution of major hydrologically closed watersheds. Important saline lakes discussed in the text are approximately located according to overall closed basin areas. Saline lake areas of Antarctica (described in Section 5.13.6) are not shown (after Cooke and Warren, 1973 Smoot and Lowenstein, 1991).

Figure 2 Major hydrologic features of hydrologically closed basins (after Eugster and Hardie, 1975) (reproduced with permission of the Geological Society of America from Geol Soc. Am. Bull 1975, 86, 319-334). Flow lines have been added here beneath the playa lake to indicate the possibility of salinity-driven density circulation, and the interaction between fresh meteoric groundwaters and recirculating evolved brines (sources Duffy and...

Climate plays a critical role in the water balance of all lakes, especially closed-basin lakes. 

Several other closed-basin regions are useful as examples of particular brine types. These include the Great Salt Lake (chloride), the lakes of East Africa (carbonate), the northern Great Plains of North America (sulfate), Death Valley (mixed), and the Australian outback (acid-chloride). Representative major ion compositions and SNORM model results for these examples are presented in Tables 3 and 4, respectively. 

At present Death Valley, California (Figure 16), does not contain a perennial lake, but it is an excellent example of a closed-basin system in which several major water types occur (Li et al., 1997). Upland weathering of a wide range of... 

Almendinger J. E. (1990) Groundwater control of closed-basin lake levels under steady-state conditions. J. Hydrol. 112, 293-318. 

Jones B. F. and Vandenburgh A. S. (1966) Geochemical influences on the chemical character of closed basins. lAHS Symp. Garda, Hydrol. Lakes Reservoirs 70, 435 -446. 

Rosen M. R. (1989) Sedimentologic, geochemical, and hydrologic evolution of an intracontinental, closed-basin playa (Bristol Dry Lake, California) a model for playa development and its implications for paleoclimate. PhD Dissertation, University of Texas at Austin. 

Street-Perrott F. A. and Roberts N. (1983) Fluctuations in closed-basin lakes as an indicator of past atmospheric circulation patterns. In Variations in the Global Water Budget (eds. F. A. Street-Perrott, M. Berman, and R. Ratchliffe). Reidel, Dordrecht, pp. 331-346. 

High arsenic concentrations can also occur in alkaline, closed-basin lakes. Mono Lake, California, USA has dissolved arsenic concentrations of (10-20) X lO pg with pH values in the range 9.5-10 as a result of the combined influences of geothermal activity, weathering of mineralized volcanic rocks, evaporation of water at the lake surface, and a thriving population of arsenate-respiring bacteria (Maest et al., 1992 Oremland et al., 2000). 

Bicarbonate ion is usually the chief anion in freshwaters. In and on silicate rocks, the HCOj concentration is usually 50 to 200 mg/L, whereas in groundwaters that contact a few percent carbonate materials up to pure limestone and dolomite, bicarbonate levels are usually in the range of 200 to 400 ppm. Seawater contains 140 mg/L HCOj. Carbonate alkalinity (CO3 ) rarely exceeds 10 mg/L. Why The presence of caustic alkalinity (free OH ) at pH s above 10 usually indicates artificial contamination of a water by, for example, Ca(OH)2 (portlandite) from the setting of concrete at newly completed wells. Cg concentrations can reach 1000 ppm as HCO3 in sodium carbonate-bicarbonate brines found in evaporative, closed basin lakes. 

The minerals nesquehonite through huntite in Table 6.1 are comparatively rare. Among these only hydromagnesite can precipitate in water at 25°C and atmospheric CO2 pressures (Fig. 6.2). Because of their high solubilities, the Mg-carbonate and hydroxy-carbonate minerals, are generally uncommon except in some evaporative cave pools, evaporating ocean embayments, arid soils, and closed-basin lakes (cf. Hostetler 1964). Nesquehonite is about 24 times as soluble as calcite at 25°C and a CO2 pressure of I bar. Similarly, at atmospheric CO2 pressure (10 bar) the solubility of hydromagnesite is 5.5 mmol/kg, whereas that of calcite is only 0.52 mmol/kg. 

This system is represented by a closed basin, made of impermeable rocks and filled in the past by a saline alkaline lake. Water in this case could not permeate downwards but only evaporate, so the deposit develops horizontally, instead of vertically as in the previous occurrence. Here pH and salinity in the fluids tend to increase, giving rise to brines, c.g., basic, alkali-rich solutions. Concentric zones of authigenic minerals are so formed, from an outer and upper ring of little altered glass and clay minerals, to zeolites, analcime and a finally alkali-feldspars. A good example for this type of occurrence is Lake Tecopa, California, where the zeolitic ring is constituted by phillipsitc, clinoptilolite and erionite, followed by the central feldspar zone [36]. 

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