The Mid­dle Dnipro megablock is one of the cen­tral struc­tur­al ele­ments of the Ukrain­ian Shield. It is sit­u­at­ed between the Inhulets–Kryvyi Rih zone and the deep fault sys­tems of the east­ern part of the Shield. The megablock is dis­tin­guished by its com­plex Archean–Proterozoic struc­ture, sig­nif­i­cant ore poten­tial, and a wide vari­ety of meta­mor­phic and intru­sive for­ma­tions.

With­in the megablock, both deeply meta­mor­phosed granite–gneiss domes and green­stone syn­cli­no­ria are devel­oped, con­tain­ing deposits of iron, gold, and non-fer­rous met­als. Sev­er­al of the old­est rocks of the Ukrain­ian Shield, exceed­ing 3.7 bil­lion years in age, are con­cen­trat­ed here.

The Mid­dle Dnipro megablock is locat­ed east of the Inhulets–Kryvyi Rih suture zone and is bound­ed by the Kryvyi Rih–Kremenchuk fault to the west and the Orikhiv–Pavlohrad fault to the east. To the north and south, it is lim­it­ed by sys­tems of mar­gin­al faults. The thick­ness of the Earth’s crust in the cen­tral part of the block reach­es 40–45 km, while beneath the green­stone struc­tures it decreas­es to 25–33 km.

The geo­log­i­cal struc­ture is dom­i­nat­ed by Archean for­ma­tions, includ­ing domes (for exam­ple, the Sak­sa­han and Demuryn domes) and uplifts (such as the Pyatykhatky uplift), between which green­stone struc­tures are sit­u­at­ed (includ­ing the Chor­tom­lyk, Kon­ka, Sura, and Biloz­er­sk struc­tures). The Kryvyi Rih–Kremenchuk struc­ture belongs to the Pro­tero­zoic.

The old­est for­ma­tions belong to the Aul series (Eoarchean and Pale­oarchean), rep­re­sent­ed by the Slavhorod, Tomakiv­ka, and Baza­vluk units. These rocks — gneiss­es, amphi­bo­lites, and crys­talline schists — occur main­ly in the east­ern part of the megablock. The Baza­vluk unit reach­es a thick­ness of up to 2800 m.

The Kon­ka series com­pris­es sev­er­al green­stone syn­cli­no­ria, includ­ing the Chor­tom­lyk, Biloz­er­sk, and Verkhivt­seve struc­tures. The series is sub­di­vid­ed into the Sura, Chor­tom­lyk, Alferiv­ka, and Solone for­ma­tions, with iso­topic ages rang­ing from 3175 to 3050 Ma. The rocks were meta­mor­phosed under green­schist facies con­di­tions and, in some areas, epidote–amphibolite facies.

The Biloz­er­sk series uncon­formably over­lies the rocks of the Kon­ka series. It includes the Mykhailiv­ka, Zapor­izhzhia, and Pereverziv­ka for­ma­tions. Quartzites, graphite–sericite schists, and iron ores occur with­in the series. Its thick­ness reach­es up to 2500 m, and its age is esti­mat­ed at 3.01–2.95 Ga.

With­in the Verkhivt­seve struc­ture, the Tepliv­ka unit is dis­tin­guished, con­tain­ing apok­er­ato­phyres, amphi­bo­lites, and fer­rug­i­nous quartzites. Its thick­ness varies from 500 to 800 m.

The Archean series con­tain sig­nif­i­cant ore resources, includ­ing iron ores (the Chor­tom­lyk and Biloz­er­sk deposits), talc–magnesite deposits, as well as occur­rences of nick­el, cobalt, cop­per, molyb­de­num, bar­i­um, stron­tium, and gold (for exam­ple, the Ser­hi­iv­ka and Bal­ka Zolota occur­rences).

The strat­i­fied rocks are close­ly asso­ci­at­ed with intru­sive, ultra­m­eta­mor­phic, and meta­so­mat­ic com­plex­es. Among the most wide­spread are pla­giogran­ites, dior­ites, and migmatites of the Dnipropetro­vsk com­plex. These rocks form dome struc­tures such as the Sak­sa­han, Kryny­chky, Zapor­izhzhia, and Demuryne domes.

With­in the region, rocks of the ancient Novopavliv­ka mafic–ultramafic com­plex occur, includ­ing ser­pen­tinites and amphi­bo­lites, with ages reach­ing up to 3700 Ma. The Olek­san­driv­ka com­plex includes bod­ies of ser­pen­tinites, dunites, gab­broids, and relat­ed rocks.

Dur­ing the Neoarchean, a num­ber of geo­log­i­cal com­plex­es were formed, includ­ing the Sak­sa­han, Demuryne, Tokiv­ka, Mokra Moskov­ka, Sura, Verkhivt­seve, Var­variv­ka, and Devladove com­plex­es. Their rocks include trond­hjemites, gran­ites, peg­matites, aplite–pegmatoid gran­ites, gab­bros, lher­zo­lites, ser­pen­tinites, and relat­ed litholo­gies.

The Mal­otern­sian­ka com­plex com­pris­es alka­line rocks such as syen­ites, foy­aites, and mar­i­upo­lites, which formed the mas­sif of the same name at the final stage of the Kryvyi Rih tectono-mag­mat­ic cycle.

With­in the megablock, three gen­er­a­tions of dyke com­plex­es are dis­tin­guished: one Neoarchean and two Pale­o­pro­tero­zoic. These are com­posed of gab­bros, gab­bro-dia­bas­es, quartz por­phyries, lam­pro­phyres, and ultra­maf­ic rocks.