Tectonic position of the Alshar Au-As-Sb-Tl deposit, Macedonia

Abstract

During the second half of the 20th century, several dozen large and medium deposits of disseminated pyrite-marcasite ores with total gold reserves of more than 6000 t and annual gold production of ~200 t were found in the Basin and Range Province, Nevada, United States [1,2]. This unique gold district is termed as the Carlin trend. The limited development of the Carlintype mineralization in other gold districts of the world is presently a debated issue. Naturally, each Carlin-type mineralization inferred beyond Nevada requires detailed investigations. In 2004, we began to study the Alshar deposit with Carlin-type mineralization together with Macedonian geologists [3]. The Alshar deposit is a large object in terms of Tl reserves and a medium reserve in terms of inferred Au reserves [3,4].The territory of Macedonia experienced long-term geological evolution. Its majority is occupied by the Serbian-Macedonian and Pelagonia crystalline massifs, separated by the Mesozoic Vardarian riftogenic graben ( Fig. 1). Macedonia is located in the SerbianMacedonian part of the Eurasian Tethys metallogenic belt. Mineralization related to the Cenozoic activation in this area is expressed in the formation of volcanoplutonic associations in the dispersed spreading environment [4]. The activation spanned the Serbian-Macedonian Massif and part of the Vardarian riftogenic zone. Superimposed structures of this period occur as narrow NW-trending grabenlike depressions complicated by local ring structures of the chamber type.Previous joint works with Macedonian geologists showed that the present-day tectonic structure of Macedonia reflects dislocations closely related to Cenozoic magmatism and productive mineralization. These dislocations were reconstructed from tectonic elements of the present-day relief surface using morphostructural analysis and deciphering aerial and satellite photographs. Based on the dislocations, we distinguished three (Oligocene-Miocene) NW-trending metallogenic zones superimposed onto the metamorphic sequence of the Serbian-Macedonian Massif. They are mainly composed of the Cenozoic tuffogenic-sedimentary and volcanic sequences and are crosscut by granitoids and dikes of intermediate composition. The metallogenic zones compose an ore belt (Fig. 1), which extends to the northwest (Serbia) and southeast (Greece and Bulgaria).From southwest to northeast, the metallogenic zones show variation in ore type and decrease in age of magmatic complexes and ores. One can see a distinct correlation between age and ore composition. Northeastward, the mineralization evolves from high-temperature (relatively low-sulfide) to low-temperature (polysulfide) types. The directed change of ore composition can be related to differentiation of ore matter in the deep-seated chambers. The ore type changes across metallogenic zones in the following way: skarn-magnetite ores (Borov Dol deposit), porphyry copper ores (Buchim), base metal copper ores (Kratovo-Zletovo), and base metal ores (Sasa and Toranica). In the SW-NE direction, the age o...

Distribution of the Total Arsenic Content in Drinking Water Obtained from Different Water Sources in the Republic of Macedonia

“…Namely, the ore bodies of the mountain consist of a large number of As containing minerals as: lorandite (TlAsS 2 ), orpiment (As 2 S 3 ), realgar (As 4 S 4 ); arsenopyrite (FeAsS), etc. [15,16].…”

“…The higher concentration of As in drinking water is due to the vicinity of the Moin area to the foothills of Kozhuf Mountain. The metallogenic area of Kozhuf Mountain volcanic complex consists of a large number of minerals containing As [15,16]. In this case, As is introduced into the water through the dissolution of minerals and ores.…”

“…Higher As content is in line with the mineral composition of the Kozhuf Mountain. The ore bodies of the mountain consist of a large number of As containing minerals [15,16]. This is also the reason for higher As concentrations in the drinking water obtained from the water supply system that draws water out from the drilled wells "Moin" which are located in a vicinity to the foothills of the Kozhuf Mountain.…”

The Dudica Epithermal Cu–Au Deposit (Republic of North Macedonia)

“…The Kozuf-Aridean metallogenic zone of Pliocene mineralization occupies a specific position in the extreme south of the RNM, extending along the Greek border. The volcanic edifices and calc-alkaline subvolcanic intrusions are confined to northeasttrending neotectonic faults (Kochneva et al, 2006).…”

Micro‐Raman spectra of extremely rare and endemic Tl‐sulfosalts from Allchar deposit

“…The Allchar (Alšar, Alshar) polychrono‐polygenetic volcano‐hydrothermal As‐Sb‐Tl‐Ba‐Hg‐Au deposit occupies the western part of the Mountain Kožuf volcanic area near the Macedonia–Greece border. A plethora of field and laboratory studies carried out regarding its geological, geochemical, mineralogical, and hydrothermal alteration revealed strikingly similar features to those which characterize Carlin‐type mineralization in the western United States .…”