Evidence for origin and alteration in the dolomites of salt diapirs, Larestan, Southern Iran

Autor: Nima Nezafati, Bijan Etemadi Abdolabadi, Ali Nokhbatolfoghahaei, Mansour Ghorbani
Rok vydání: 2017
Předmět:
Zdroj: Carbonates and Evaporites. 34:389-403
ISSN: 1878-5212
0891-2556
DOI: 10.1007/s13146-017-0399-5
Popis: Dolomites are well-known minerals; belonging to the Infra-Cambrian Hormuz Series lies within the salt domes of southern Iran. In this paper, the origin and alteration of dolomitic rocks of Paskhand and Deh-kuyeh salt diapirs in the area of Larestan (southern Iran) are investigated. Based on petrographic (size and fabric) studies, we recognize four dolomite types that consist of very fine-to-fine crystalline dolomite (D1), neomorphic dolomite (D2), fine-to-medium crystalline euhedral-to-subhedral dolomite (D3), and pore- and fracture-filling dolomite (D4). The dolomite samples with up to 26% iron can be called ferruginous dolomites. Some igneous rock patches to gehter with hydrothermal iron veins are observable in the salt domes of Larestan. Oxygen and carbon isotope values of black and white, and altered red dolomite of Paskhand and Deh-kuyeh salt domes, are equal to − 12.35 to − 18.78 for δ18OPDB and − 5.48 to − 8.49 for δ13CPDB; values enriched δ180 with low-temperature (~ 70 °C) conditions are related to D1 dolomites and values depleted δ180 with higher temperatures (~ 270 °C) are related to D3 and D4 dolomites. The most important source for secondary dolomites is deeper hydrothermal and catchment sources, which ascended through faults during the intrusion. Meteoric waters can be mentioned as less important sources for these types of dolomites. We reported sassolite B(OH)3 mineral in Deh-kuyeh salt diapir for the first time in this paper. This mineral is only observed in the areas which have famous riftings Fumarol. Therefore, in this paper, the existence of sassolite in the studied area could be considered one of the most important the origin of the composing elements of Hormuz rocks from fumarols which are formed in an extensional regime.
Databáze: OpenAIRE
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