Reference

Huntite from the weathering crust of the serpentinites of Kempirsaya (southern Urals)

Huntite from the weathering crust of the serpentinites of Kempirsaya (southern Urals). Ivanov, O. K.; Pal'gueva, G. V. (USSR). Tr. Inst. Geol. Geokhim., Ural. Nauchn. Tsentr, Akad. Nauk SSSR, 118, 84-7 (Russian) 1976. CODEN: TGGKB8. DOCUMENT TYPE: Journal CA Section: 53 (Mineralogical and Geological Chemistry) Huntite [19569-21-2] is described from weathered, nontronitized serpentinites. It contains CaO 15.53, MgO 34.26, CO2 48.19, and H2O +1.03 wt.%. The unit cell parameters are a 5.660, b 9.040, and c 8.480 .ANG.. The x-ray and DTA data are included.

Simulation of carbonate diagenetic processes: formation of dolomite, huntite and monohydrocalcite by the reactions between nesquehonite and brine

Simulation of carbonate diagenetic processes: formation of dolomite, huntite and monohydrocalcite by the reactions between nesquehonite and brine. Davies, Peter J.; Bubela, Bohdan; Ferguson, James (Bur. Miner. Resour., Canberra, Aust.). Chem. Geol., 19(3), 187-214 (English) 1977. CODEN: CHGEAD. DOCUMENT TYPE: Journal CA Section: 53 (Mineralogical and Geological Chemistry) A tank system contg. sediments and brine chosen to simulate an evaporative shallow-water org.-rich sedimentary basin was allowed to evolve for 10 months. Early diagenetic reactions between nesquehonite [14457-83-1] and brine resulted in a marked increase in alky. The 1st major change was the pptn. of monohydrocalcite spherules which formed a crust between supernatant liq. and sediment. Cores of the nesquehonite layer showed dissoln. of the nesquehonite and the formation of huntite [19569-21-2] and protohydromagnesite, followed by the formation of Mg-rich dolomite [16389-88-1], and then dolomite of stoichiometric proportions. Calcite [13397-26-7] pptd. with dolomite within the nesquehonite layer. A 2nd crust, pptd. within a layer of decaying filamentous algae, between the nesquehonite and calcite layers was composed of calcite, dolomite, and halite [14762-51-7]. Pptn. within the nesquehonite layer was controlled by reactions between brine and nesquehonite, leading to dissoln. of nesquehonite and hydrolysis of carbonate. The formation of huntite and dolomite appears to have been aided by a high CO2-3 concn. in soln., which was affected by the high salinity, and maintained by the continued dissocn. of nesquehonite.