Devonian Dolomites from the Holy Cross Mts, Poland: A New Concept of the Origin of Massive Dolomites Based on Petrographic and Isotopic Evidence

Abstract

A new model based on the effective hydrothermal pump was invoked for the middle and lower Upper Devonian dolomites from the Holy Cross Mountains (Świetokrzyskie Mts), mid-southern Poland. The hybridized seawater was recycled periodically through the deep-seated (quasi-rifted) fault system up to the floor of the basin during the Eifelian through lower Frasnian time, bringing about the massive dolomitization of carbonate sediments. Apart from the dolomites, stratified and irregular concentrations of clay minerals, iron, and manganese oxides and hydroxides with admixtures of pyrite and occasionally barite formed during that time. Numerous dolomite structural forms connected with various hydrothermal pulses were recorded. The $$\delta^{13}C$$, and $$\delta^{18}O$$ of dolomites range from $$1.61 to -6.30\%_0$$ and from $$-0.52 to - 10.74\%_{0}$$, respectively. The $$delta^{13}C$$ shift in the dolomites is characteristic of that for the associated limestones. Distinct fluctuation in trace element compositions...