The Ukrain­ian Shield is a large-scale deep uplift of the Pre­cam­bri­an base­ment of the East Euro­pean Plat­form, locat­ed near its south­west­ern mar­gin. At the end of the Pro­tero­zoic and dur­ing the Pale­o­zoic, it formed as an inde­pen­dent geo­log­i­cal struc­ture due to the devel­op­ment of the Dnipro–Donets Basin.

The Pre­cam­bri­an is the pre-Cam­bri­an geo­log­i­cal epoch that makes up most of Earth­’s geo­log­i­cal his­to­ry (over 3.8 Ga). Before its sep­a­ra­tion from the East Euro­pean plat­form, the Ukrain­ian shield, togeth­er with the Voronezh crys­talline mas­sif, was part of a large ter­ri­to­ry — the Sar­ma­t­ian meso­con­ti­nent, which in the late Pro­tero­zoic was unit­ed with the Vol­ga-Ural and Scan­di­na­vian meso­con­ti­nents.

Spa­tial­ly, the Ukrain­ian Shield occu­pies the cen­tral axi­al part of Ukraine, extend­ing from the coast of the Sea of Azov to the bor­der with Belarus for near­ly 1,000 km. Its width varies from 150 to 450 km. The area of Pre­cam­bri­an rock out­crops reach­es 136,500 km², and includ­ing its slopes—256,600 km², which is more than one-third of Ukraine’s ter­ri­to­ry. Crys­talline rocks are exposed in many regions of the coun­try.

The Ukrain­ian Shield has a com­plex geo­log­i­cal struc­ture: a Pre­cam­bri­an crys­talline base­ment with a fold­ed archi­tec­ture, com­posed of meta­mor­phic and mag­mat­ic rocks, over­lain by a Meso-Ceno­zoic sed­i­men­ta­ry cov­er rang­ing in thick­ness from 100–200 m to more than 500 m on its margins.The Pre­cam­bri­an base­ment is sub­di­vid­ed into six megablocks with dif­fer­ent geo­log­i­cal char­ac­ter­is­tics:

• Volyn granite–gneiss–schist megablock;
• Podil­lian gran­ulite megablock;
• Bug-Rosyn gran­ulite-amphi­bo­lite megablock;
• Prya­zov­ian granulite–diaftorite megablock;
• Mid­dle Dnipro granite–greenstone megablock;
• Inhul granite–gneiss–schist megablock;

Each megablock has its own unique geo­log­i­cal fea­tures, although com­mon char­ac­ter­is­tics can also be observed. The base­ment of the megablocks is main­ly com­posed of gneiss­es and crys­talline schists, while the upper units dif­fer sig­nif­i­cant­ly and include green­stone sedimentary–volcanogenic sequences, deeply meta­mor­phosed terrigenous–sedimentary rocks, and fly­sch-like vol­canogenic formations.These data indi­cate a com­plex evo­lu­tion of the con­ti­nen­tal crust, involv­ing mul­ti­ple stages of destruc­tion, rework­ing, and accre­tion of micro­con­ti­nents.

Bound­aries between megablocks are often com­pli­cat­ed by so-called suture zones—tectonic zones char­ac­ter­ized by major fault sys­tems, meta­mor­phism, and mag­ma­tism. These zones are evi­dence of col­li­sion­al amal­ga­ma­tion of sep­a­rate crustal blocks. The main suture zones of the Ukrain­ian Shield include:

• Teteriv zone — between the Volyn and Podil­lian megablocks
• Bru­syliv zone — between the Podil­lian and Bug–Rosyn megablocks
• Obod­niv zone — between the Buzko-Rosyn and Mid­dle Dnipro megablocks
• Inhulets–Turia zone — sep­a­rat­ing the Mid­dle Dnipro and Inhul megablocks
• Zaporizhzhia–Pryazovian zone — between the Mid­dle Dnipro and Prya­zov­ian blocks
• Kalyuzh­na zone — an inter­nal suture struc­ture with­in the Prya­zov­ian megablock

These zones reflect deep-seat­ed dis­lo­ca­tions formed as a result of Archean and Pro­tero­zoic tec­ton­ic events, includ­ing accre­tion and col­li­sion of micro­tec­ton­ic blocks that con­tributed to the for­ma­tion of the ancient con­ti­nen­tal crust of the East Euro­pean Plat­form.