Geology of Tanzania

The geology of Tanzania began to form in the Precambrian, in the Archean and Proterozoic eons, in some cases more than 2.5 billion years ago.

Tanzania has extensive, but poorly explored and exploited natural resources, including coal, gold, diamonds, graphite and clays.

The Dodoman Belt stretches for 480 kilometers, broadening westward and is composed of banded quartzites, aplite, sericitic schist, pegmatite and ironstone.

The Nyanzian Belt, by contrast, is mainly acid and basic basalt, dolerite, trachyte, rhyolite and tuff in separated zones south and east of Lake Victoria.

The Kavirondian is believed to be the remains of a molasse that formed by the Nyanzian as evidenced by sedimentary rocks such as mudstone, conglomerate as well as volcanics and grit.

The belt is associated with Bukoban Series conglomerates, bedded sandstones and basalt flows which extend from the Ugandan border and terminate at the Rukwa Rift.

The formation of the belt is related to the widespread Pan-African orogeny and most rocks are highly metamorphosed pyroxene-gneiss, charnockite, biotite, hornblende.

In the Tanzania region, situated in the interior of Pangaea, the Karoo Supergroup deposited between the Late Carboniferous and the Early Jurassic, with sequences of terrestrial sediments.

These sediments formed diverse rock units including sandstones, conglomerates, tillite, shale, red and gray mudstones and periodically, limestone deposits.

The Sanya Plain and Kahe Basin around Mount Kilimanjaro have a mix of pyroclastic flow debris and alluvial sediments, creating some of the best aquifer potential.

Water quality varies, with periodic nitrate and salinity issues and better productivity from limestone and sandstone, compared with shale and marl.

International companies have been attracted to Tanzania by large graphite reserves, formed in kyanite gneiss and altered ore deposits.