Diamond-bearing fluidolites in the junction area of East European Platform and Urals fold region

Abstract

Research subject. To characterize the Sylva fluidogenic-explosive complex, which was established in the junction area of the West Ural thrust megazone (head of the Sylva River) and the eastern wing of the Yuryuzano-Sylva depression of the Pre-Ural trough. Materials and methods. The authors' materials collected during research works at GSA200/2 sheet O-40-XXIX (Shalinskaya Ploshchad), as well as those collected during the work under the Priority 2030 Federal Program, were used. Data on the geology, petrochemistry, petrography, structural and tectonic position of clastogenic rock associations in the area of influence of the Main West Ural thrust were employed. Experimental data were obtained using a TESCAN VEGA LMS electron microscope equipped with an Xplore 30 energy dispersive X-ray spectroscopic prefix, and an URS-55 X-ray unit (Ural State Mining University), as well as CPM-35 and Shimadzu EDX-8000 spectrometers and an XRD-7000 diffractometer (Geoanalitik Centre, Zavaritsky Institute of Geology and Geochemistry of the Ural Branch of the Russian Academy of Sciences). Results. For the first time, the mineralogical-petrographic and chemical compositions of diamond-bearing rocks of the Sylva fluidogenic complex were established. Diamonds and minerals contained in the studied rocks were determined by XRD (sanidine, analcime, etc.). The conducted analysis of the rocks suggests their possible fluid-magmatic genesis, which is indicated by mineralogical features, including accessory minerals-indicators of diamond content, the presence of ellipsoid and teardrop-shaped volcanic glass, finely-dispersed bulk and poorly-rolled unsorted fragments of igneous and sedimentary rocks. Conclusions. The results obtained indicate the possibility of manifestation of Early Mesozoic phreatic volcanism in the studied area, which led to the transfer of the Sylva diamond complex and accessory minerals by fluidolites.