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Titolo:
ISOTOPIC COMPOSITION OF GYPSUM HYDRATION WATER IN SELECTED LANDFORMS FROM CENTRAL IRAN
Autore:
KHADEMI H; MERMUT AR; KROUSE HR;
Indirizzi:
SASKATCHEWAN CTR SOIL RES,DEPT SOIL SCI,51 CAMPUS DR SASKATOON SK S7N5A8 CANADA SASKATCHEWAN CTR SOIL RES,DEPT SOIL SCI SASKATOON SK S7N 5A8 CANADA UNIV CALGARY,DEPT PHYS & ASTRON CALGARY AB T2N 1N4 CANADA
Titolo Testata:
Chemical geology
fascicolo: 3-4, volume: 138, anno: 1997,
pagine: 245 - 255
SICI:
0009-2541(1997)138:3-4<245:ICOGHW>2.0.ZU;2-4
Fonte:
ISI
Lingua:
ENG
Soggetto:
HYDROGEN; SULFATE; SOILS; O-18;
Keywords:
GYPSIFEROUS SOILS; HYDRATION WATER; STABLE ISOTOPES; IRANIAN SOILS;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
36
Recensione:
Indirizzi per estratti:
Citazione:
H. Khademi et al., "ISOTOPIC COMPOSITION OF GYPSUM HYDRATION WATER IN SELECTED LANDFORMS FROM CENTRAL IRAN", Chemical geology, 138(3-4), 1997, pp. 245-255

Abstract

During its formation, hydration water of gypsum may be preserved, dueto lack of sufficient contact with soil moisture in arid environments. If this hypothesis is valid, the isotopic composition of the hydration water of gypsum may provide very useful information, particularly about the paleo-hydrological conditions in soils and sediments. Little information is available on the stable isotope geochemistry of gypsum hydration water in arid regions. This study was initiated to measure the delta D and delta(18)O values of the gypsum crystallization water in different landforms to determine their relationship with meteoric water and to identify the possible mechanism(s) for the large gypsum accumulation in the Isfahan region, central Iran. Samples from different horizons of twelve pedons covering two adjacent soil landscapes were analyzed. The delta D and delta(18)O values of eight rainwater samples from different seasons and water samples from the Zayandehrud river inthe area were also determined. The mean and standard deviation of delta D and delta(18)O values of gypsum hydration water were -68.75 +/- 5.51 parts per thousand and +1.11 +/- 1.68 parts per thousand for colluvial fans and -56.5 +/- 7.28 parts per thousand and +4.47 +/- 2.07 parts per thousand for plateaus. The slope of Delta delta D/Delta delta(18)O = +3 and the significant positive correlation (P < 0.01) between the isotopic composition of the gypsum crystallization water (both delta D and delta(18)O) and the amount of gypsum in the soils indicated that evaporation is the major process for the accumulation of gypsum. The delta D and delta(18)O values confirmed that gypsum was formed likely before the Quaternary era and paleowater, from a slightly more moistand/or colder climate, or different climatic pattern in the past, is still preserved (partly or entirely) in the gypsum hydration water. Differences found in the isotopic composition of gypsum hydration water,with respect to landscape position, may be useful to establish, more accurately, segments of a landscape in arid environment.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 02/12/20 alle ore 18:18:51