Marine evaporites

Stewart, F.H.

doi:10.3133/pp440y

Cited by 45 publications

(24 citation statements)

References 45 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…In toto, in our work we used 13,000 analyses of clays and shales, including analyses of 2100 composite samples made up from 31,000 specimens; 3000 analyses of sandy rocks, including 1783 composite The average composition of the evaporites of platform and fold zones of the continents was calculated on the basis of the volumetric proportions of halide salts and sulfates, which are 75:25 [37]. To estimate the average chemical composition of salts, which are taken to be the same for evaporite deposits of the platforms, geosynclines and orogenic regions, we used the compositions of rock salt, sylvanite and camallite rocks, taken from Borisenkov's data bank on the evaporite deposits of the USSR, chiefly the salts of the Nepa basin (East Siberia), and compared with Stewart's data [222]; altogether we used 4315 analyses. The proportions of the main types of evaporite deposits were taken from Zharkov's data [37]-approximately 99% halite and 1% K and Mg salts.…”

Section: Historical Trends In the Chemical Composition Of The Sedimenmentioning

confidence: 99%

Chemical Constitution of the Earth's Crust and Geochemical Balance of the Major Elements

Ronov

Yaroshevskiy

Migdisov

1991

International Geology Review

122

View full text Add to dashboard Cite

Section: Historical Trends In the Chemical Composition Of The Sedimenmentioning

confidence: 99%

Chemical Constitution of the Earth's Crust and Geochemical Balance of the Major Elements

Ronov

Yaroshevskiy

Migdisov

1991

International Geology Review

122

View full text Add to dashboard Cite

“…The primary sulphide sources of arsenic in study area are absent, but the adsorbed species is Fe-oxy-hydroxides (ferrihydrite, goethite) (Cornell and Schwertmann 1996) in clay minerals Pfeifer et al 2001). Few studies have also reported the presence of apatite mineral in charnockite rocks (Chidambaram 2000 andRamanathan 1956) which is believed to be the source of arsenic (Stewart 1963). …”

Section: Distribution Of Arsenicmentioning

confidence: 98%

A study on the arsenic concentration in groundwater of a coastal aquifer in south-east India: an integrated approach

Chidambaram

Thilagavathi

Thivya

et al. 2016

Environ Dev Sustain

View full text Add to dashboard Cite

The occurrence of arsenic in drinking water and its detrimental effects have drawn much attention in recent years. Several studies have been conducted in the deltaic plains of River Ganga, NE part of the India, and in other countries, but no systematic study was conducted in South India on occurrence of arsenic in groundwater. The main aim of this study is to determine the level of arsenic in groundwater and to understand the relation with other geochemical parameters of groundwater in the south-eastern coastal aquifer at Kalpakkam region, India. This region is represented by three different lithologies, viz. charnockites, flood plain alluvium and marine alluvium. Twenty-nine representative samples of groundwater were collected and analysed for major ions, metals and isotopes such as 2 H and 18 O. In addition, geophysical method was also attempted to understand the subsurface condition. The spatial variation in arsenic (As) indicates that higher concentration was observed around the landfill sites and irrigated regions, which was supported by geochemical, statistical and isotopic inferences. The variation in the As with depth, lithology and sources has been clearly brought out. Though the values of As does not exceed the drinking water permissible limit (10 mg/l), it has reached a near permissible level of 8.7 ppb. Hence, it is essential to understand the geochemical behaviour of As for a proper future management of the water resource in the study area.

show abstract

“…Los contenidos de Sr en la fracción yesífera de la unidad salina se encuentran incluidos en los rangos de variación para los yesos, que no suelen sobrepasar las 2500 ppm (Buller, 1973;Dean, 1978;Stewart, 1963 "' .,.…”

Section: Geoquímicaunclassified

“…De esta forma, en la fracción yesífera de la unidad salina el contenido medio de Fe es de 193 ppm, mientras que en la unidad yesífero-detrítica es de 84 ppm. Ambos valores se encuentran dentro del rango de variación de este elemento en yesos (Stewart, 1963y Dean, 1978. El resto de elementos trazas analizados (Li, Na, K) se encuentran también dentro de estos rangos de variación, pero con unos valores que no permiten diferenciar de una forma clara las dos unidades yesíferas.…”

Section: F"~munclassified

Untitled

Ordóñez¹,

Fort²,

Bustillo³

1989

Estud. geol.

View full text Add to dashboard Cite

RESUMENEn el Terciario de la Cuenca de Madrid existen dos unidades sedimentarias de carácter yesí-fero. Ambas unidades están constituidas por yesos con diferentes características, aunque su separación es dificil en diversos afloramientos debido a intensos procesos de yesificación que transforman las texturas primarias en una textura común secundaria formada por un mosaico macrocristalino de yeso. El objetivo de este trabajo se centra en la aplicación de la geoquímica de elementos traza en la discriminación de las dos unidades. En este sentido, el Sr, Mg, y Fe pueden ser unos elementos muy útiles para separar ambas unidades.También se llevó a cabo un análisis factorial con los resultados geoquímicos. Los valores de los factores obtenidos permiten situar la posición de la ruptura sedimentaria entre ambas unidades. Esta ruptura queda claramente diferenciada por un cambio simultáneo en ambos factores, de valores negativos a positivos.Los resultados obtenidos indican que los yesos detriticos de la Unidad Superior se han formado por el desmantelamiento de anhidritas de la Unidad Inferior. Estas anhidritas, previamente han sido yesificadas en un ambiente de alta concentración de ione¡. Palabras clave: Evaporitas, elementos traza, rupturas sedimentarias, Cuenca de Madn'd. ABSTRAerTwo sedimentary Unities of gypsum deposits are defined in tbe Tertiary of the Madrid Basin, Spain. 80th Unities are formed by gypsum materials witb different features altbough tbe separation between the lower and the upper Unities can be very difficult in sorne outcrops. It is due to strong processes of gypsification which transform tbe primary textures in a secondary texture formed by macrocrystalline mosaics of gypsum. Tbe objective of tbis work is related to the aplication of trace element geochemistry to discriminate between lower and upper Unities. So, Sr, Mg, and Fe can be a useful elements to separate lower Unity from Upper one.A factor analysis was also carried out with tbe geochemical results. Tbe values of tbe factors obtained let us to define tbe position of tbe sedimentary rupture between the two Unities. Tbis position is c1early differentiated by a simultaneous change in botb factors from negative to positive values.Tbe results obtained show that terrigenous gypsum (Upper Unily) are formed by erosion of anhidrites from Lower Unity. Tbese anhidrites, previously, have been transformed to gypsum in a environrnent of high salinity.

show abstract

Marine evaporites

Cited by 45 publications

References 45 publications

Chemical Constitution of the Earth's Crust and Geochemical Balance of the Major Elements

Chemical Constitution of the Earth's Crust and Geochemical Balance of the Major Elements

A study on the arsenic concentration in groundwater of a coastal aquifer in south-east India: an integrated approach

Untitled

Contact Info

Product

Resources

About