Orange River Pegmatite Belt, Southern Africai

Regional Level Types
Orange River Pegmatite Belt	Pegmatite Field
Southern Africa	- not defined -

The ORPB is a ∼400 km long and ∼40–80 km wide belt found within the Namaqua Metamorphic Province (NMP) and geographically situated on the boundary between the Northern Cape Province of South Africa and the Ikaras region of Namibia, consisting of Paleoproterozoic and Mesoproterozoic sedimentary, volcanic, and intrusive rocks that formed and deformed during their accretion to the Kaapvaal Craton.
In the ORPB, an approximate 45,000 pegmatite bodies were emplaced within this region over a protracted period from 1025 Ma to 945 Ma, during the final stages of the Namaqua Orogeny except for an older pegmatitic phase that has been dated to 1104 Ma. Pegmatites in the ORPB are spatially grouped, where the western section of the NNP is primarily characterized by Lithium-Cesium-Tantalum (LCT), spodumene-bearing pegmatites, while the eastern section is primarily characterized by Niobium-Yttrium-Fluorine (NYF) pegmatites based on the classification of Černý (1991). Their emplacement ages generally follow a progressive trend from the Vioolsdrif Domain (in the west) to the Kakamas Domain (in the east), though some variations exist. LCT pegmatites are generally found to be older, with U-Pb monazite ages clustering between ∼1038 and 960 Ma, representing a prolonged ∼80 Myr history of emplacement that coincided with the late Namaqua orogenic events. NYF pegmatites, particularly those in the Kakamas Domain, have titanite ages of 1043–1025 Ma for simple pegmatite dykes and younger monazite ages of 991–962 Ma for complex pegmatite dykes, suggesting that NYF magmatism persisted beyond the peak of LCT emplacement and became progressively enriched in rare metals over time. In the ORPB, pegmatites are commonly associated with hydrothermal alteration such as metasomatism, greisenization, albitization, kaolinization, and silicification. These types of alteration are particularly evident in mining operations such as Bleskop mine (Noumas I pegmatite), where tantalite and spodumene are extracted. Gemstones including rose quartz are commonly associated with pegmatites in the ORPB, and in some cases, the rose quartz is highly fractured. Typically, pegmatite bodies intrude granitic host rocks, exhibiting sharp contacts with the host rock at moderate to high angles, or interfinger with diorite intrusions. Mineralized pegmatites are closely associated with diorite intrusions throughout the study area.

The pegmatites of the ORPB are not linked with plutons at current exposure level. The vast number of pegmatites (<35 000) represent a range in pegmatite types. The pegmatites range from “simple”, often muscovite or biotite bearing, unzoned to weakly zoned and barren pegmatites to chemically complex rare earth element (REL) class with exotic minerals rich in Be, Li, Ta, etc. The REL-type pegmatites are mostly LCT in character. However, NYF pegmatites are found in the areas around Riemvasmaak and Kakamas in the Kakamas Domain. These complex REL-type pegmatite of the ORPB are found together in “swarms” that create an apparent regional zonation with respect to pegmatite mineralogy and chemistry, while the bulk of encountered pegmatites are simple and barren. Given their mineralogy of LCT-type pegmatites within the ORPB (in particular, the occurrence of beryl and exotic lithium phases such as spodumene or lepidolite) at least some of the pegmatites must represent some final stage fractionates of much larger felsic magma bodies. Additionally, the fact that the ORPB pegmatites are observed in the field to intrude metasediments of the Namaqua-Natal Belt might be used to suggest that they were sourced from partial melting of these metasediments during deformation of the NNMP at the time of pegmatite emplacement.

Geochronology

Mineralization age: Cambrian : 512 ± 12 Ma

Important note: This table is based only on rock and mineral ages recorded on mindat.org for this locality and is not necessarily a complete representation of the geochronology, but does give an indication of possible mineralization events relevant to this locality. As more age information is added this table may expand in the future. A break in the table simply indicates a lack of data entered here, not necessarily a break in the geologic sequence. Grey background entries are from different, related, localities.

Geologic Time				Rocks, Minerals and Events
Phanerozoic
	Paleozoic
		Cambrian
			Cambrian Series 2	ⓘ Zircon 512 ± 12 Ma Bremen Occurrence, Karasburg West, ǁKaras Region, Namibia

Fossils

There are 4 fossil localities from the PaleoBioDB database within this region.

These data are provided on an experimental basis and are taken from external databases. Mindat.org has no control currently over the accuracy of these data.

Occurrences	10
Youngest Fossil Listed	66.0 Ma (Late/Upper Cretaceous)
Oldest Fossil Listed	635 Ma (Neoproterozoic)
Stratigraphic Units	Unit No. Occurrences Age Dwyka 2 295.5 - 290.1 Ma (Permian) Nama - Huns 3 635 - 541 Ma (Neoproterozoic) Nama - Nomtsas 1 635 - 530 Ma (Neoproterozoic to Cambrian)
Fossils from Region	Click here to show the list.
Accepted Name Hierarchy Age Gastropoda class Animalia : Mollusca : Gastropoda 295.5 - 290.1 Ma Permian Ornithopoda unranked clade Animalia : Chordata : Ornithischia : Ornithopoda 89.3 - 66 Ma Late/Upper Cretaceous Plantae kingdom Plantae 89.3 - 66 Ma Late/Upper Cretaceous Araucaria genus Plantae : Tracheophyta : Pinopsida : Pinales : Araucariaceae : Araucaria 89.3 - 66 Ma Late/Upper Cretaceous Vulcanobatrachus mandelai species Animalia : Chordata : Osteichthyes : Anura : Vulcanobatrachus : Vulcanobatrachus mandelai 89.3 - 66 Ma Late/Upper Cretaceous Treptichnus genus Treptichnus 635 - 530 Ma Neoproterozoic to Cambrian Namacalathus hermanastes species Animalia : Cnidaria : Namacalathus : Namacalathus hermanastes 635 - 541 Ma Neoproterozoic Aphanaia haibensis species Animalia : Mollusca : Bivalvia : Myalinida : Kolymiidae : Aphanaia : Aphanaia haibensis 295.5 - 290.1 Ma Permian
Fossil Localities	Click to show 4 fossil localities

Localities in this Region

Other Regions, Features and Areas that Intersect

References