The Irumide Belt is a Mesoproterozoic

Mesoproterozoic

The Mesoproterozoic Era is a geologic era that occurred between 1600 Ma and 1000 Ma . The Mesoproterozoic was the first period of Earth's history with a respectable geological record. Continents existed in the Paleoproterozoic, but we know little about them...

 terrane

Terrane

A terrane in geology is short-hand term for a tectonostratigraphic terrane, which is a fragment of crustal material formed on, or broken off from, one tectonic plate and accreted or "sutured" to crust lying on another plate...

 of deformed basement and folded supracrustals, which occurs along the southern margin of an Archaean/Palaeoproterozoic unit called the Bangweulu Block

Bangweulu Block

The Bangweulu Block is a cratonic unit that forms part of the Congo craton of central Africa. The Bangweulu Block however consists of Palaeoproterozoic granitoids and volcanics, and is overlain by a Palaeoproterozoic continental sedimentary succession, the Mporokoso Group, and does not preserve...

 in Zambia

Zambia

Zambia , officially the Republic of Zambia, is a landlocked country in Southern Africa. The neighbouring countries are the Democratic Republic of the Congo to the north, Tanzania to the north-east, Malawi to the east, Mozambique, Zimbabwe, Botswana and Namibia to the south, and Angola to the west....

.

The Irumide Belt comprises deformed crystalline basement units dated at 2.7 Ga and between 2.05 and 1.93 Ga, unconformably

Unconformity

An unconformity is a buried erosion surface separating two rock masses or strata of different ages, indicating that sediment deposition was not continuous. In general, the older layer was exposed to erosion for an interval of time before deposition of the younger, but the term is used to describe...

 and in places structurally overlain by a supracrustal sequence of shallow water quartzite

Quartzite

Quartzite is a hard metamorphic rock which was originally sandstone. Sandstone is converted into quartzite through heating and pressure usually related to tectonic compression within orogenic belts. Pure quartzite is usually white to gray, though quartzites often occur in various shades of pink...

s and pelite

Pelite

Pelite is old and currently not widely used field terminology for a clayey fine-grained clastic sediment or sedimentary rock, i.e. mud or mudstone. It is equivalent to the Latin-derived term lutite. More commonly, metamorphic geologists currently use pelite for a metamorphosed fine-grained...

s, the Muva

Muva

The Muva is a term coined by E.H. Ackermann for a folded supracrustal shallow water succession of quartzites and pelites in the Irumide Belt of Zambia. The "Muva" was first described by A...

 Supergroup, in which sparse volcanic tuff

Tuff

Tuff is a type of rock consisting of consolidated volcanic ash ejected from vents during a volcanic eruption. Tuff is sometimes called tufa, particularly when used as construction material, although tufa also refers to a quite different rock. Rock that contains greater than 50% tuff is considered...

s have given ages of between 1.88 and 1.85 Ga. This complex is intruded by limited granitoid

Granitoid

A granitoid or granitic rock is a variety of coarse grained plutonic rock similar to granite which mineralogically are composed predominately of feldspar and quartz. Examples of granitoid rocks include granite, quartz monzonite, quartz diorite, syenite, granodiorite and trondhjemite. Many are...

s at ca. 1.66-1.55 Ga and an extensive suite of syn-orogenic plutonic rocks at between 1.05 and 1.00 Ga.