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| Titel |
Exploring the hydrochemical evolution of brines leading to sylvite precipitation in ancient evaporite basins |
| VerfasserIn |
Dioni Cendón, Juan José Pueyo, Carlos Ayora, Javier García Veigas, Marie-Madeleine Blanc-Valleron |
| Konferenz |
EGU General Assembly 2010
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 12 (2010) |
| Datensatznummer |
250034819
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| Zusammenfassung |
| Sylvite is a very common mineral in ancient evaporite deposits. Due to the absence of current
deposits, the natural geochemical mechanism/s for synsedimentary sylvite precipitation and
accumulation are not well understood. Numerous sylvite deposits or portions of them have
been described as a result of diagenesis (i.e. Sergipe subbasin, Brasil). However, a number of
deposits have been described as synsdimentary or being formed during primary
evaporite deposition. It is the last group of deposits that can be studied to better
understand the hydrochemical processes taking place in the brine at the onset of sylvite
precipitation.
The Salt IV sylvite beds from the Mulhouse potash basin, Alsace (France) have been
described as synsedimentary in origin (LOWENSTEIN and SPENCER, 1990; CENDóN et al.,
2008). While sylvite in itself does not contain fluid inclusions viable for micro analysis,
primary textures in neighboring halite are used as a proxy to understand brine evolution. Two
halite-sylvite cycles from the B1 and B2 layers of the potash lower seam were selected. These
exhibited clear primary halite crystal textures with sylvite adapting to an irregular
halite sedimentary surface and finishing with a flat surface. The nine halite samples,
selected at centimeter scale, provided close to 100 single fluid inclusion analyses,
representing both the transition towards sylvite precipitation and the post sylvite
precipitation.
The fluid inclusion analyses revealed strong fluctuations in K concentration, well over the
analytical error ( |
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