Hook granite massif
14°56′34″S 26°3′21″E / 14.94278°S 26.05583°E The Hook granite massif is a large formation in central Zambia formed around 550 million years ago during the Pan-African orogeny. It lies in the inner part of the
Lufilian arc.[1]
Today, the south-western extension of the massif lies under the Kafue National Park.[2]
Formation
Field studies and
U-Pb (uranium-lead) dating show that the massif is a large composite batholith that has intruded into the upper Katangan (Kundelungu) strata of sediments in the Lufilian arc during or after tectonic
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 took place around 560–570 Ma; and the major tectonic activity had ended by around 530–540 Ma.[1]
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 Zambezi belt during the Pan-African orogeny.[1]
References
- ^ .
- ^ D.B. Fanshawe (December 2010). "VEGETATION DESCRIPTIONS OF THE UPPER ZAMBEZI DISTRICTS OF ZAMBIA" (PDF). Biodiversity Foundation for Africa. Retrieved 2012-06-08.