The Hook granite massif is a large formation in central

Zambia Zambia (), officially the Republic of Zambia, is a landlocked country at the crossroads of Central Africa, Central, Southern Africa, Southern and East Africa, although it is typically referred to as being in Southern Africa at its most cent ...

formed around 550 million years ago during the

Pan-African orogeny The Pan-African orogeny was a series of major Neoproterozoic orogenic events which related to the formation of the supercontinents Gondwana and Pannotia about 600 million years ago. This orogeny is also known as the Pan-Gondwanan or Saldanian Oro ...

. It lies in the inner part of the

Lufilian arc The Lufilian Arc (or Lufilian Belt) is part of a system of orogenic belts in southern Africa formed during the Pan-African orogeny, a stage in the formation of the Gondwana supercontinent. It extends across eastern Angola, the Katanga Province of ...

. Today, the south-western extension of the massif lies under the

Kafue National Park Kafue National Park is the largest national park in Zambia, covering an area of about 22,400 km² (similar in size to Wales or Massachusetts). It is one of the largest parks in Africa and is home to 152 different species of mammals. The park ...

Formation

Field studies and U-Pb (uranium-lead) dating show that the massif is a large composite

batholith A batholith () is a large mass of intrusive igneous rock (also called plutonic rock), larger than in area, that forms from cooled magma deep in Earth's crust. Batholiths are almost always made mostly of felsic or intermediate rock types, such ...

that has intruded into the upper Katangan (Kundelungu) strata of sediments in the Lufilian arc during or after

tectonic Tectonics (; ) are the processes that control the structure and properties of the Earth's crust and its evolution through time. These include the processes of mountain building, the growth and behavior of the strong, old cores of continents k ...

activity. Sample U-Pb dates for syntectonic granite in the massif are 559±18 and 566±5 Ma, and for post-tectonic granite 533±3 Ma. These show that the Kundelungu sediments date to before 570 Ma; the deformation of the inner Lufilian arc and voluminous syntectonic granite

plutonism Plutonism is the geologic theory that the igneous rocks forming the Earth originated from intrusive magmatic activity, with a continuing gradual process of weathering and erosion wearing away rocks, which were then deposited on the sea bed, re- ...

took place around 560–570 Ma; and the major tectonic activity had ended by around 530–540 Ma. The Hook massif is bounded to the south by the Mwembeshi dislocation, a Pan-African transcurrent shear zone. Syntectonic rhyolite intruded in this shear zone dates to 551±19 Ma, so the transcurrent shearing happened about the same time as the batholith intrusion and was probably due to the same causes. Syntectonic and post-tectonic granite plutonism also took place around the same time in the

Damara belt The Damara orogeny was part of the Pan-African orogeny. The Damara orogeny occurred late in the creation of Gondwana, at the intersection of the Congo and the Kalahari cratons.; ; ; ; The Damara orogeny involved the suturing of the Congo– São ...

in Namibia, indicating a link with the Lufilian arc and

Zambezi belt The Zambezi Belt is an area of orogenic deformation in southern Zambia and northern Zimbabwe. It is a segment of a broader belt lying between the Congo Craton and the Kalahari Craton, which also includes the Lufilian Arc and the Damaran Belt. The ...

during the Pan-African orogeny.

References

Geology of Africa {{palaeo-geo-stub