Geology of Belarus

Thegeology of Belarusbegan to form more than 2.5billionyears ago in thePrecambrian,although many overlying sedimentary units deposited during thePaleozoicand the currentQuaternary.Belarusis located in the eastern European plain. From east to west it covers about 650 kilometers while from north to south it covers about 560 kilometers, and the total area is about 207,600 square kilometers. It borders Poland in the north, Lithuania in the northwest, Latvia and Russia in the north, and Ukraine in the south. Belarus has a planar topography with a height of about 160 m above sea level. The highest elevation at 346 meters above sea level isMt. Dzerzhinskaya,and the lowest point at the height of 80 m is in theNeman Rivervalley.

The soils are soddypodzolsandpeatbogs are common. Belarus is situated onCratonsbasement is made ofArcheanand earlyProterozoiccrystalline basement rocks and covered by terrigenous,volcanogenic,andcarbonaterocks that date to theRiphean(a stratigraphic division of the Proterozoic in Russia and Scandinavia) through the last 2.5 million years of theQuaternary.

Stratigraphy & Geologic History

The land surface in Belarus is mostly covered withQuaternarydeposits.In the quarries inMikashevichy,Precambrianbasement rocks is uncovered, whileJurassic,Devonian,Cretaceous,Neogene,andPaleocenedeposits are exposed throughout most of the rest of the country. Data about the different stratigraphic subsections was collected from numerous boreholes in Belarus during the Soviet period.

Archean-Early Proterozoic crystalline basement

The internal structure of the crystalline basement resulted from the long-term transformation of the primary proto-oceanic crust to well-defined continental crust. This took place when the early Archean basalt proto-oceanic crust formed. The rocks formed and metamorphosed intogranulitebasite, andgneiss.

The accumulation offlyschand volcanogenic-silica-iron, andgreywacketook place in the late Archean and at the beginning of theProterozoicage. They were later transformed intoschistandamphibolitegneisscomplexes through regional metamorphism, and then deposited in the granulite gneissic basement as the structure evolved.

West Belarus is dominated by rocks of the EarlyArcheanShchuchin series,which is composed ofamphibolite,crystallineschists,andgneissesthat are metamorphosed under moderate pressure togranulitegrade on the sequence of metamorphicfacies.This series is about 5 to 7 kilometers thick. In the east of the region, most of the rocks found there are Early ArcheanKulazhin Series.These rocks are represented bybiotitegneisses andgarnet-biotitic gneiss about 5 kilometers thick. Most of the upper Archean rocks include theOkolovo Seriesand theOzery Series.The Okolovo rocks are plagiogneisses, amphibolites, and schists embedded with ferruginousquartzite.The Ozery Series is made up of an amphibolite gneiss complex. The total thickness of both the Okolovo and the Ozery is about 10 kilometers. These rocks are mostly present in central Belarus.

In the south, the series is made up ofchlorite-sericiteschists,rhyolites,quartzite,andesite,anddacites.In this part of the country, the series has a thickness of about 500 meters, and reachesgreenschistmetamorphicfacies.Some of the rocks that can be found in abundance are ultrametamorphic, intrusive, andmetasomaticcomplexes—that include lower Archean metagabbro,granites,diabase,granitoids,granodiorites,enderbite-charnockite,and Late Archean metagabbros.

Late Proterozoic

LateProterozoicdeposits include theVendianand theRipheanrocks. Riphean rocks are found in large paleotroughs and small depressions. Vendian rocks cover most of the country—about 85%. The Riphean rocks are mostly made up of volcanogenic-sedimentary strata includingtrachandesites,quartz- rhyolites,quartzites,schists,sandstones,andconglomerates.These rocks are encountered in isolated local boreholes—usually at around 140 meters deep.

The middle Riphean series is composed of theSherovichy Series.These rocks can be seen as apolymicticarkosesandstone strata with gravestone underlining it and quartzitic sandstone on top. On the other hand, the upper Riphean fills theVolyn-Orsha paleotroughthat extends from northeast to southwest across the Belarus regions. These series form the Belarus Series

Vendian deposits are divided into three subseries from bottom to top, including theVilcha Series,Volyn SeriesandValdai Series.The Vilcha series is made up oftillite,clayandsandstonesthat originated during theNeoproterozoicglaciations.. They form a sheet 310 meter thick on the surface. This layer is mostly composed of andesite,dacites,basalts,tuff,trachyliparites withtuff,and tuff-siltstone intercalations with thicknesses of about 550 meters. The Valdai series can be seen as a layer of alternating clays, siltstones, sandstones, and some gravels. In most cases, this layer is about 300 meters thick.

Phanerozoic (538.8 million years ago-present)

This layer is represented by all the systems discoursed above, and it is widely spread in the region of Belarus. TheOrdovician,Cambrian,andSiluriandeposits are mostly found in the SW and NW of Belarus. In most of the other parts of the country, thePhanerozoicbegins with middleDevoniandeposits. However, in uplifted areas it starts with theCenozoicandMesozoicsediments.

TheCambrianhas two stages: lower and middle stages. The lower consists of theBaltic SeriesandVysokovsk Series.The Baltic series is composed of clays, sandstones, and siltstones up to 180 meter thick. The Vysokovsk Series consists of the same components as the Baltic Series but is a little thicker (about 250 meter thick). The middle stage consists of layers of siltstones, sandstones and rarely clays of about 115 meters thick.

TheOrdovicianhas the same components as the Cambrian with additional limestone, sandstone and clay intercalations at the bottom. This layer is about 153 meters thick in the northwest and 53 meter thick in the southwest. TheSilurianis about 640 meters thick in the southwest and 60 meter thick in the northwest. This layer consist of limestone,marls,anddolomites.TheDevonianincludes all the stages, with the early Devonian predominantly found in central Belarus.

Tectonics

TheBelarusian Baltic Granulite Beltextends from north southwards for a distance of about 1000 kilometers and is approximately 100–200 kilometers wide. This belt is made-up of metabasic rocks that are products of ultra-metamorphic transformation. It includes granulite blocks that are separated byblastomylonitezones andnappe-thrust structures and linear folding.. Magnetic field research has revealed a series of intense magnetic band anomalies. In the southeast of Belarus is theBraguin Granulite Massifthat measures about 150 to 70 kilometers wide, and shows magnetic anomalies of low intensity. Another granulite massif is the triangularVitebsk Massifwhich has a composition is similar to that of the Braguin Massif. In northernmost Belarus, the Latvian Saddle is about 200 by 150 kilometers wide, separating the Baltic and the Moscow Synclines. The depth of the ridge is about 0.6 kilometers.

Natural resource geology

Layers ofevaporiterock in a mine in Soligorsk, a site converted tohalotherapy

There are large iron deposits in the basement rocks. For example, in theNovoselkideposits there are about 26% iron deposits at a depth of about 150 m. TheOkolovahas iron deposits of about 35% at a depth of about 260 meters. High volume iron ore reserves are found at a depth of about 700 meters, and they are estimated to hold about t 700 million tons of reserves. Some estimates suggest as much as 1.5 billion tons. The ore contains cobalt, vanadium, titanium, silver and gold. At theGlushkovichyarea andMikashevichyarea, are large deposits of gneisses and granites.