The article presents the mineralogical characteristics of epigenetic iron mineralization in the Paleozoic core of the Holy Cross Mountains. The occurrence of epigenetic Fe mineralization, known in the literature as “Zagnańsk-type ”, has so far been associated with the Łysogóry region of the Holy Cross Mountains, and the classic location is the Zachełmie quarry near Zagnańsk. Moreover, other occurrences of this mineralization in the Łysogóry region were also recorded in Wzdół-Kamieniec and Rudki. In recent years, manifestations of this type of mineralization have also been found in the Kielce region of the Holy Cross Mountains, including: the Laskowa quarry near Kostomloty and the Józefka quarry near Górno. The hematite ores and the accompanying mineralization from outcrops known from the literature and from new locations were investigated. Detailed microscopic examinations allowed determining the order of crystallization of individual minerals and distinguishing two stages of Fe mineralization, differing in both mineralogical composition and precipitation conditions. The relationship of this mineralization with diagenetic processes taking place in the Devonian-Carboniferous basin and with the tectonic processes of the Variscan orogeny was also demonstrated. Such mineralization shows close connections with tectonic zones, which emphasizes its epigenetic nature at all locations studied. A general model of the formation of Zagnańsk-type Femineralization was also created, which is applicable to the entire Paleozoic core of the Holy Cross Mountains. In the metallogenesis of the Holy Cross Mountains, this mineralization occurs after (or almost simultaneously) the oldest dolomites and manifestations of silicification of carbonate rocks, and precedes the fundamental stage of development of polymetallic sulphide mineralization with carbonates, and of barite mineralization, which is commonly recorded in this region.
Metamorphic rocks of greenstone facies (phyllites) have been discovered quite recently in the Łysogóry region of the Holy Cross Mountains. The following minerals predominate in the mineral composition of these rocks: bright mica (sericite), quartz, chlorites, rutile, pyrophyllite, xenotime, pyrite, tourmaline, apatite and monacite, while chalcopyrite, sphalerite and galena are also present in mineral veins. The phyllites from Podmąchocice are intensely tectonically deformed, while their metamorphism displays a syndeformation character. The age of the tectonic-metamorphic processes has been initially estimated based on their relation to the silicification process. The phyllites are cut by numerous hydrothermal mineral veins, including quartz-chlorite-apatite ones. These veins occur as small post-tectonic and syntaxial forms, a few centimetres long and up to 1 cm thick. In the central parts of the veins, apatite forms colourless crystals, up to 1 mm long and up to 0.1mm thick. The age of the apatites was determined by means of the laser ablation system combined with the mass spectrometer. The results of isotopic measurements were reduced using the “Vizual Age” reduction program. The U-Pb age has been estimated to ~389 ± 18 Ma (upper intercept) that points to the maximum Devonian age (Eifelian/Givetian) of formation of the quartz-apatite veins. This is the first dating that point sto hydro thermal activity of th is age in the study area. As the veins cut discordantly the metamorphic rocks, the metamorphism itself may be older than the apatite age.
The geosite Zygmuntówka (Sigismund ) quarry, located at Czerwona Góra near Chęciny in SW part of the Holy Cross Mountains, is the oldest and the most famous among the so-called Chęciny „marble” quarries which provided stones for constructing numerous important buildings in the region and beyond. Upper Permian conglomerates (Czerwona Góra Formation), with a thickness of several tens of metres, outcrop in this area. The conglomerates are clast- and locally mud-supported and consist of light grey and beige carbonate pebbles and cobbles chaotically distributed within the reddish-brown silty-carbonate-ferriferous matrix. The conglomerates represent continental alluvial fan deposits deposited under arid and semiarid climate conditions. The quarry, of a regional rank, is well suited for both geoeducation and geotourism purposes.
The PGI-NRI conducts geological research on the documentation of occurrence of REE deposits in Poland. The deposit potential may be related to the formation of Lower Cretaceous phosphorites from the NE margin of the Holy Cross Mountains. Two phosphorite deposits were exploited in this region in the past: Chałupki (1936-1959) and Annopol (1952-1970). From the Chałupki old mine dump, 34 samples of fine-grained sand were collected. The pseudonodules were extracted from this sand. The sand from the dump is composed of quartz, francolite (carbonate-rich fluorapatite) Ca5(PO4,CO3)3F, illite and a small amount of feldspar, calcite and heavy minerals. The heavy fraction is composed of zircon, monazite and rutile. Sand has a low content of REE ranging from 47.56 to 185.26ppm. The phosphorite pseudonodules underwent a detailed mineralogical and chemical analysis. They are composed of francolite, quartz, illite, glauconite, feldspar and minor heavy minerals: zircon and monazite. For the first time, the whole spectrum of REE was analysed in pseudonodules. The I.REE content in the nodules ranges from 177.37 to 354.18ppm. This level of REE indicates a serious need for further exploration and research of phosphorite pseudonodules within the whole Lower Cretaceous phosphorite series and moreover, also in the Eocene phosphorite formation in the Lublin region.
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