Ganigobis Formation

{{short description|Late Carboniferous to Early Permian geological formation of the Dwyka Group in Southern Africa}}

{{Infobox rockunit

| name = Ganigobis Formation

| image =

| caption =

| type = Geological formation

| age = Gzhelian-Artinskian
{{fossil range|302|297}}

| period = Artinskian

| prilithology = Shale, conglomerate, sandstone

| otherlithology = Tuff

| namedfor = Ganigobis

| namedby =

| region = ǁKaras Region
Northern Cape

| country = Namibia, South Africa

| coordinates = {{coord|25.9|S|18.0|E|display=inline,title}}

| paleocoordinates = {{coord|56.0|S|35.9|W|display=inline}}

| unitof = Dwyka Group

| subunits = Ganigobis Shale Member

| underlies = Ecca Group

| overlies = Nama Group

| thickness = up to {{convert|240|m|ft|abbr=on}}

| extent = Aranos & Karoo Basins
Kalahari Craton

| area =

| map = Damara-Orogen mit Damara-Gürtel, Kaoko-Gürtel und Gariep-Gürtel.png

| map_caption = Geologic map of Namibia with the Ganigobis Formation partly cropping out in the southern area (orange)

| location_ts = Ganigobis, Fish River Canyon

| thickness_ts = {{convert|155|m|ft|abbr=on}}

}}

The Ganigobis Formation is a Late Carboniferous (Gzhelian) to Early Permian (Artinskian) geologic formation of the Dwyka Group in the ǁKaras Region of southeastern Namibia and the Northern Cape of South Africa. The widespread formation was deposited in the Aranos and Karoo Basins of southern Africa.

Description

The Ganigobis Formation is an extensive unit with a maximum thickness of {{convert|240|m|ft}} evidenced in the Vreda borehole.Bangert et al., 2000, p.266 The conglomerates, sandstones, shales and tuff of the formation were deposited in a glacio-lacustrine to marine environment.[https://paleobiodb.org/classic/displayStrata?geological_group=Dwyka%20Shale&formation=Ganigobis&group_formation_member=Ganigobis Ganigobis Formation] at Fossilworks.orgBangert, 2000, p.21 The Ganigobis Formation provides fossil fish as well as bivalves (e.g. Nuculopsis), gastropods (e.g. Peruvispira), scyphozoa (e.g. Conularia), crinoid stalks, foraminifera (Hyperammina, Ammodiscus, Glomospira, Ammobacculites and Spiroplectammina),Bangert, 2000, p.60 sponges and sponge spicules, radiolaria, coprolites and permineralised wood.Bangert, 2000, p.3

Zircons of the Ganigobis Shale Member yield SHRIMP-ages of 302-300 Ma. This dates the uppermost part of the second deglaciation sequence in southern Namibia to the

Late Carboniferous (Gzelian) and provides a minimum age for the onset of Karoo-equivalent marine deposition. The age of the uppermost argillaceous part of the third deglaciation sequence (297 Ma) was determined from zircons of a tuffaceous bed sampled in a roadcut in the Western Cape Province, South Africa.

Fossil content

Among others, the following fish fossils are reported from the formation:[https://paleobiodb.org/classic/displayCollResults?collection_no=131110 Ganigobis] at Fossilworks.org[https://paleobiodb.org/classic/displayCollResults?collection_no=131113 Wesselton Mine, Kimberley] at Fossilworks.org[https://paleobiodb.org/classic/displayCollResults?collection_no=131078 Ganigobis, near Tses Station] at Fossilworks.org

References

= Bibliography =

{{citation |last1=Bangert |first1=B. |last2=Stollhofen |first2=H. |last3=Geiger |first3=M. |last4=Lorenz |first4=V. |year=2000 |title=Fossil record and high-resolution tephrostratigraphy of Carboniferous glaciomarine mudstones, Dwyka Group, southern Namibia |url=http://www.mme.gov.na/files/publications/0bd_Bangert%20et%20al_Fossil%20record%20-%20Dwyka%20Fm.pdf |journal=Communications of the Geological Survey of Namibia |volume=12 |pages=265–276 |accessdate=2018-08-26}}
{{citation |last=Bangert |first=Berthold |year=2000 |title=Tephrostratigraphy, petrography, geochemistry, age and fossil record of the Ganigobis Shale Member and associated glaciomarine deposits of the Dwyka Group, Late Carboniferous, southern Africa (PhD thesis) |url=https://opus.bibliothek.uni-wuerzburg.de/opus4-wuerzburg/frontdoor/deliver/index/docId/179/file/bangert.pdf |publisher=Julius-Maximilians-Universität Würzburg |pages=1–242 |accessdate=2018-08-26}}

Ganigobis Formation

Description

Fossil content

See also

References

= Bibliography =

Further reading