Post-magmatic hydrothermal mineralization associated with Cretaceous picrite (Outer Western Carpathians, Czech Republic): interaction between host rock and externally derived fluid

作者：Dolnicek Zdenek^*; Urubek Tomas; Kropac Kamil

来源：Geologica Carpathica, 2010, 61(4): 327-339.

DOI：10.2478/v10096-010-0019-y

• Outer Western Carpathians
• stable isotopes
• strontium isotopes
• fluid-rock interaction
• veins
• fluid inclusions
• amygdules
• REE
• picrite

Mineralogy, fluid inclusions, C, O, S, Sr isotopes and trace elements have been studied in amygdule and vein mineralization hosted by the Lower Cretaceous effusive picrite at Honaova hurka (Silesian Unit, Flysch Belt of the Outer Western Carpathians). Besides dominating dolomite, magnesite, siderite, quartz, calcite, chlorite, glauconite, fluorite, barite, pyrite and millerite were also identified. The parent fluids are characterized by low temperatures (<50-170 degrees C), low salinities (0.4 to 3.7 wt. % NaCl eq.), low content of strong REE-complexing ligands, delta O-18, delta C-13 and delta S-34 ranges of 0/+ 14 parts per thousand SMOW, 0/-9 parts per thousand PDB and similar to 0 parts per thousand CDT, respectively, and initial Sr-87/Sr-86 ratios much more radiogenic (0.7060 to 0.7068) than those of host picrite (0.7042 and 0.7046). The fluids are interpreted to be predominantly of external origin, derived from mixing of seawater with diagenetic waters produced by dewatering of clay minerals in the associated tlysch sediments. The isotope and REE signatures indicate interaction of at least a part of fluids with sedimentary carbonates. The interaction of fluids with host picrite led to strong alteration of rock-forming minerals and leaching of some elements (Mg, Ni, S, partly also REE) that widely participated during precipitation of vein- and amygdule-hosted mineral phases.

• 出版日期2010-8