Geology of Angola

Last updated

Erosion created cliffs at Miradouro da Lua. Miradouro da Lua (Angola).jpg
Erosion created cliffs at Miradouro da Lua.

The geology of Angola includes large areas of Precambrian age rocks. The west of the country is characterized by meta-sedimentary rocks of Proterozoic age including tillites assigned to the Bembe System. Overlying these are a thick pile of limestones and other marine sediments laid down during the Mesozoic and Cenozoic eras. Amidst the Proterozoic sequence are areas of crystalline basement dating from the Archaean. More Archaean basement rocks form the Kasai Craton in northeastern Angola. In the north, within the Cassanje Graben are clastic sediments and volcanic rocks of the Karoo Supergroup. Kimberlites and carbonatites resulting from magmatic activity during the Karoo period are found along a northeast-southwest line through the country. Continental sediments of the Kalahari Group are widespread in eastern Angola. [1]

Contents

Fossils

The Mesozoic of Angola is very rich of fossil vertebrates, namely marine reptiles such as turtles ( Angolachelys [2] ), mosasaurs and plesiosaurs, [3] related with the opening of South Atlantic. [4] Only a couple of terrestrial fossils have been collected, including the unique dinosaur Angolatitan adamastor . [5]

Geohazards

Aquifers and ground water have been polluted due mining activities in the country. [6] :40

Economic geology

The larger part of Angola's income derives from oil production and by 2008 the country was Africa's second largest producer of crude petroleum. Angola is also the fourth largest producer of diamonds in Africa. Diamonds are obtained both from alluvial deposits and from the hundreds of kimberlite pipes which are scattered along a northeast – southwest line through Angola. The country is also a gold producer, the most important source being alluvium originating from Archaean greenstones dominantly around Cabinda. Angola also has, as yet largely untapped, copper, gypsum, phosphate, iron ore, manganese and other base metal reserves. [7]

Related Research Articles

<span class="mw-page-title-main">Bengo Province</span> Province of Angola

Bengo is a province of Angola. Its capital is Caxito. It has an area of 31,371 square kilometres, and its population as of the 2014 Census was 356,641. The province was created in 1980 by dividing the original province of Luanda into Bengo and a new smaller province of Luanda.

<span class="mw-page-title-main">Mosasaur</span> Extinct marine lizards of the Late Cretaceous

Mosasaurs are an extinct group of large aquatic reptiles within the family Mosasauridae that lived during the Late Cretaceous. Their first fossil remains were discovered in a limestone quarry at Maastricht on the Meuse in 1764. They belong to the order Squamata, which includes lizards and snakes.

<span class="mw-page-title-main">Adamastor</span> Mythological character created by the Portuguese poet Luís de Camões

Adamastor is a mythological character created by the Portuguese poet Luís de Camões in his epic poem Os Lusíadas, as a personification of the Cape of Good Hope, symbolizing the dangers of the sea and the formidable forces of nature challenged and ultimately overcome by the Portuguese during the Age of Discovery. Adamastor manifests itself out of a storm.

<i>Globidens</i> Extinct genus of lizards

Globidens is an extinct genus of mosasaurid oceanic lizard classified as part of the Globidensini tribe in the Mosasaurinae subfamily. Globidens belongs to the family Mosasauridae, which consists of several genera of predatory marine lizards of various sizes that were prevalent during the Late Cretaceous. Specimens of Globidens have been discovered in Angola, Brazil, Morocco, Syria and the United States. Among mosasaurs, Globidens is probably most well known for the highly rounded, globe-like teeth that give it its name.

<span class="mw-page-title-main">Octávio Mateus</span> Portuguese dinosaur paleontologist and biologist

Octávio Mateus is a Portuguese dinosaur paleontologist and biologist Professor of Paleontology at the Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa. He graduated in Universidade de Évora and received his PhD at Universidade Nova de Lisboa in 2005. He collaborates with Museu da Lourinhã, known for their dinosaur collection.

<i>Euclastes</i> Extinct genus of turtles

Euclastes is an extinct genus of sea turtles that survived the Cretaceous–Paleogene mass extinction. The genus was first named by Edward Drinker Cope in 1867, and contains three species. E. hutchisoni, was named in 2003 but has since been reassigned to the genus Pacifichelys, while E. coahuilaensis named in 2009 was reassigned as Mexichelys coahuilaensis in 2010.

<i>Angolasaurus</i> Extinct genus of lizards

Angolasaurus is an extinct genus of mosasaur. Definite remains from this genus have been recovered from the Turonian and Coniacian of Angola, and possibly the Coniacian of the United States, the Turonian of Brazil, and the Maastrichtian of Niger. While at one point considered a species of Platecarpus, recent phylogenetic analyses have placed it between the (then) plioplatecarpines Ectenosaurus and Selmasaurus, maintaining a basal position within the plioplatecarpinae.

<i>Angolachelys</i> Extinct genus of turtles

Angolachelys is an extinct genus of African marine turtle which existed in Angola during the Turonian stage of the Late Cretaceous. The type species is Angolachelys mbaxi. The type MGUAN-PA includes skull, jaw, and postcranial fragments found in the Tadi Beds of the Itombe Formation.

<i>Angolatitan</i> Extinct genus of titanosauriform dinosaurs

Angolatitan is a genus of titanosauriform sauropod dinosaur from the Upper Cretaceous. It is also the first non-avian dinosaur discovered in Angola. The genus contains a single species, Angolatitan adamastor, known from a partial right forelimb. Angolatitan was a relict form of its time; it was a Late Cretaceous basal titanosauriform, when more derived titanosaurs were far more common.

The geology of Egypt includes rocks from Archaean - early Proterozoic times onwards. These oldest rocks are found as inliers in Egypt’s Western Desert. In contrast, the rocks of the Eastern Desert are largely late Proterozoic in age. Throughout the country this older basement is overlain by Palaeozoic sedimentary rocks. Cretaceous rocks occur commonly whilst sediments indicative of repeated marine transgression and regression are characteristic of the Cenozoic Era.

The geology of Botswana plays a significant part in the country's economy. The basement rocks of the Kaapvaal-Zimbabwe craton extend into Botswana whilst in the east and southeast, metamorphic rocks of Archaean age are dominant. A younger cover of Karoo rocks and post-Cretaceous Kalahari Group sediments conceal the western margins of these older rocks and largely conceal Proterozoic orogenic belts too. This younger stratum was laid down in the Kalahari Basin underlying large parts of the centre of the country. In the northwest of Botswana, more recent sediments overlie rocks of Meso- and Neoproterozoic age rocks, belonging probably to the Damara Belt.

The Bentiaba is a river in southern Angola. Its mouth is at the Atlantic Ocean near the commune of Bentiaba in Namibe Province.

<i>Cardiocorax</i> Extinct genus of reptiles

Cardiocorax is an extinct genus of elasmosaurid known from the Late Cretaceous Mocuio Formation of Namibe Province, southern Angola. It contains a single species, Cardiocorax mukulu.

<span class="mw-page-title-main">Globidensini</span> Tribe of lizards

The Globidensini or Globidentatini are a tribe of mosasaurine mosasaurs, a diverse group of Late Cretaceous marine squamates. Members of the tribe, known as "globidensins" or "globidensine mosasaurs", have been recovered from North America, Europe, Africa and Asia. The tribe contains the genera Globidens, Carinodens, Igdamanosaurus, Harranasaurus and Xenodens. Features of the maxilla and digits make the placement of Carinodens and Xenodens in the tribe uncertain; some researchers have suggested that they may be more appropriately placed in the Mosasaurini.

<span class="mw-page-title-main">Geology of Zambia</span>

The geological history of Zambia begins in the Proterozoic eon of the Precambrian. The igneous and metamorphic basement rocks tend to be highly metamorphosed and may have formed earlier in the Archean, but heat and pressure has destroyed evidence of earlier conditions. Major sedimentary and metamorphic groups formed in the mid-Proterozoic, followed by a series of glaciations in the Neoproterozoic and much of the Paleozoic which deposited glacial conglomerate as well as other sediments to form the Katanga Supergroup and rift-related Karoo Supergroup. Basalt eruptions blanketed the Karoo Supergroup in the Mesozoic and Zambia shifted to coal and sandstone formation. Geologically recent windblown sands from the Kalahari Desert and alluvial deposits near rivers play an important role in the modern surficial geology of Zambia. The country has extensive natural resources, particularly copper, but also cobalt, emeralds, other gemstones, uranium and coal.

The Itombe Formation is a geological formation of the Kwanza Basin in Angola dated to the Coniacian stage of the Late Cretaceous. The environment of deposition is shallow marine. Reptile fossils have been recovered from the Tadi beds locality within the formation, including the dinosaur Angolatitan, the mosasaurs Angolasaurus and Mosasaurus iembeensis and the turtle Angolachelys. The Itombe formation was formerly considered Turonian in age, but new data suggests to be Coniacian.

<span class="mw-page-title-main">Angolachelonia</span> Extinct clade of turtles

Angolachelonia is a clade of extinct turtles from the Late Jurassic to Paleogene of Eurasia. The group is defined as all taxa derived from the ancestor of the type genus Angolachelys and Solnhofia, a definition that could potentially encompass a clade of entirely marine turtles. Angolachelonia was originally inclusive of only Solnhofia, Angolachelys and Sandownia when originally conceived by Octavio Mateus and colleagues in 2009, but later phylogenetic analyses by Serjocha Evers and Roger Benson in 2018 unites the family Sandownidae, including Angolachelys and Sandownia among other taxa, with the entirely Late Jurassic clade Thalassochelydia, where Solnhofia may be a basal member. While the placement of Solnhofia is weak and the clade that Angolachelonia represents may change with further analysis, the clade of Sandownidae and Thalassochelydia is well-supported, and does not collapse despite the uncertain evolutionary history of the group. Three alternative potential origins of Angolachelonia sensu Evers and Benson are shown below.

Gnathomortis is an extinct genus of marine lizard belonging to the mosasaur family. Fossils of Gnathomortis have been recovered from the Early Campanian Mancos Shale of Colorado. The genus contains a single species, G. stadtmani, considered a species of the related Prognathodon up until its 2020 redescription. It was a large mosasaur measuring 10.5 metres (34 ft) long.

The Mocuio Formation is a Late Cretaceous sedimentary rock formation found in southern Angola. It extends from the latest Campanian to the Early Maastrichtian. Many vertebrate fossils have been collected from the formation.

<i>Bentiabasaurus</i> Extinct genus of mosasaurs

Bentiabasaurus was a gracile plotosaurine mosasaur from the Late Cretaceous Mocuio Formation of Angola. The type and only species of the genus, B. jacobsi, was described in 2023 by Michael Polcyn, Anne Schulp and António Gonçalves.

References

  1. "Angola Geology, The Extractive Industries Source Book". Extractive Industries. Retrieved October 18, 2016.
  2. Mateus, Octávio; Jacobs, Louis; Polcyn, Michael; Schulp, Anne S.; Vineyard, Diana; Buta Neto, André; Telles Antunes, Miguel (December 2009). "The Oldest African Eucryptodiran Turtle from the Cretaceous of Angola". Acta Palaeontologica Polonica. 54 (4): 581–588. doi: 10.4202/app.2008.0063 .
  3. Schulp, AS; Polcyn, MJ; Mateus, O; Jacobs, LL; Morais, ML. "New mosasaur material from the Maastrichtian of Angola, with notes on the phylogeny, distribution and palaeoecology of the genus Prognathodon". Publicaties van het Natuurhistorisch Genootschap.
  4. LL Jacobs, O Mateus, MJ Polcyn, AS Schulp… 2015 Cretaceous paleogeography, paleoclimatology, and amniote biogeography of the low and mid-latitude South Atlantic Ocean - Bulletin de la Société géologique de France, 2009
  5. Angolatitan adamastor, a new sauropod dinosaur and the first record from Angola O Mateus, LL Jacobs, AS Schulp, MJ Polcyn, TS Tavares, A Buta Neto, ... Anais da Academia Brasileira de Ciências 83 (1), 221–23
  6. Schlüter, Thomas (April 19, 2008). Geological Atlas of Africa: With Notes on Stratigraphy, Tectonics, Economic Geology, Geohazards, Geosites and Geoscientific Education of Each Country. Springer Science & Business Media. Retrieved October 18, 2016.
  7. "Angola, Oil and Gas, The Extractive Industries Source Book". Extractive Industries. Archived from the original on April 19, 2015. Retrieved October 18, 2016.