Galula Formation Explained

Galula Formation
Period:Late Cretaceous
Age:Aptian-Campanian
~
Type:Geological formation
Prilithology:Sandstone
Otherlithology:Conglomerate, mudstone
Unitof:Red Sandstone Group
Subunits:Mtuka Member, Namba Member
Underlies:Unconformity with Nsungwe Formation
Overlies:Unconformity with Karoo Supergroup or basement
Thickness:600-
Coordinates:-7.1°N 31.2°W
Paleocoordinates:-28.8°N 16.5°W
Region:Rukwa, Mbeya Region
Extent:African Great Lakes, Rukwa Rift Basin
Namedfor:Galula
Namedby:Roberts et al.
Year Ts:2010
Thickness Ts:520m (1,710feet)
Location Ts:Galula Coalfields
Coordinates Ts:-8.6821°N 32.8926°W

The Galula Formation is a geological formation located south of Lake Rukwa in Tanzania, part of the Red Sandstone Group of the Rukwa Rift Basin. Along with the unconformably overlying Oligocene Nsungwe Formation. It is divided into two members, the lower Mtuka Member and the upper Namba Member.[1]

The age of the deposit is poorly constrained, with the Mtuka Member likely being Aptian to Cenomanian in age, while the Namba Member being Cenomanian to Campanian in age based on Geomagnetic reversals.[2] It is correlated with the Dinosaur Beds of Malawi.

The formation is fossiliferous, with Dinosaurs and Crocodyliformes being known from the formation.

Geology

Lithology

The Lithology of the formation is a sequence of red, pink, purple and occasionally white colored sandstones, conglomerates and mudstones. The Mtuka member is 160–180 m thick in the type section, and is typified by coarser sandstone, a higher frequency of conglomerates, higher proportions of extraformational clasts, thicker and a greater frequency of overbank siltstone and mudstone lenses and a higher proportion of paleosols. While the Namba member is between 340–360 m in the type section, and is less variable in facies, predominated by very fine-to medium-grained sandstones with less overbank mudstone and siltstone lenses.

Vertebrate paleofauna

Fish

Fish of the Galula Formation
Genus SpeciesLocality Stratigraphic position Abundance Notes Images
LupaceradotusL. useviaensis RRBP 2004-06-30Lungfish
CeratodontidaeIndeterminateMtuka MemberLungfish

Crocodyliformes

Crocodyliformes of the Galula Formation
Genus SpeciesLocality Stratigraphic position Abundance Notes Images
Pakasuchus[3] P. kapilimaiRRBP 2007-04Namba Member[Two] skulls and an articulated skeleton.A notosuchian crocodyliform with mammal-like teeth.
Rukwasuchus[4] R. yajabalijekunduNamba 2Middle Namba memberA partial skull and isolated teeth.A notosuchian crocodyliform, and the only known sub-Saharan peirosaurid from Africa.
NotosuchiaIndeterminateNamba Member

Dinosaurs

Dinosaurs of the Galula Formation
Genus SpeciesLocality Stratigraphic position Abundance Notes Images
Mnyamawamtuka[5] M. moyowamkiaMtuka MemberAn anterior cervical vertebral neural arch, cervical vertebral centra, partial dorsal vertebrae, sacral neural arch, partial sacral centra, sacral ribs, caudal vertebral neural arches, centra, chevrons, numerous dorsal rib fragments, scapula, sternal plate, humeri, partial ulna, metacarpal I, metacarpal III, partial ischium, partial pubis, partial femora, tibiae, fibula, metatarsal I, metatarsal II, metatarsal III, metatarsal IV, metatarsal V, pedal phalanges, ungual, and numerous unidentifiable fragments.A basal lithostrotian titanosaur with heart-shaped caudal vertebrae.
Rukwatitan[6] R. bisepultusLocality RRBP 2007-02 (Namba 2)Middle Namba memberPosterior cervical vertebrae, partial anterior dorsal vertebral neural arch, anterior caudal vertebrae, middle caudal vertebrae, chevrons, multiple partial dorsal ribs, distal scapula, partial coracoids, humerus, partial ulna, ilium, and proximal pubis.A basal lithostrotian titanosaur.
Shingopana[7] S. songwensisTZ-07Namba MemberAn angular, partial anterior cervical vertebra, partial middle-to-posterior cervical vertebrae, partial cervical ribs, partial dorsal ribs, humerus, pubis, and many incomplete and/or unidentifiable fragments pertaining to the axial skeleton.A lithostrotian titanosaur.
Theropoda[8] IndeterminateMtuka and Namba MembersA pair of articulated proximal caudal vertebrae, and 11 teeth.An indeterminate theropod.

Mammals

Notes and References

  1. Roberts. Eric M.. O’Connor. Patrick M.. Stevens. Nancy J.. Gottfried. Michael D.. Jinnah. Zubair A.. Ngasala. Sifael. Choh. Adeline M.. Armstrong. Richard A.. May 2010. Sedimentology and depositional environments of the Red Sandstone Group, Rukwa Rift Basin, southwestern Tanzania: New insight into Cretaceous and Paleogene terrestrial ecosystems and tectonics in sub-equatorial Africa. Journal of African Earth Sciences. 57. 3. 179–212. 10.1016/j.jafrearsci.2009.09.002. 2010JAfES..57..179R . 1464-343X.
  2. Widlansky. Sarah J.. Clyde. William C.. O'Connor. Patrick M.. Roberts. Eric M.. Stevens. Nancy J.. March 2018. Paleomagnetism of the Cretaceous Galula Formation and implications for vertebrate evolution. Journal of African Earth Sciences. 139. 403–420. 10.1016/j.jafrearsci.2017.11.029. 2018JAfES.139..403W . 1464-343X. free.
  3. O’Connor. Patrick M.. Sertich. Joseph J. W.. Stevens. Nancy J.. Roberts. Eric M.. Gottfried. Michael D.. Hieronymus. Tobin L.. Jinnah. Zubair A.. Ridgely. Ryan. Ngasala. Sifa E.. August 2010. The evolution of mammal-like crocodyliforms in the Cretaceous Period of Gondwana. Nature. 466. 7307. 748–751. 10.1038/nature09061. 20686573. 2010Natur.466..748O . 4405106 . 0028-0836.
  4. Sertich. Joseph J. W.. O’Connor. Patrick M.. 2014-04-16. A new crocodyliform from the middle Cretaceous Galula Formation, southwestern Tanzania. Journal of Vertebrate Paleontology. 34. 3. 576–596. 10.1080/02724634.2013.819808. 2014JVPal..34..576S . 16644660 . 0272-4634.
  5. Eric. Gorscak. Patrick M.. O’Connor. 2019. A new African titanosaurian sauropod dinosaur from the middle Cretaceous Galula Formation (Mtuka Member), Rukwa Rift Basin, southwestern Tanzania. PLoS ONE. 14. 2. e0211412. 10.1371/journal.pone.0211412. 6374010. 30759122. 2019PLoSO..1411412G . free .
  6. Gorscak. Eric. O'Connor. Patrick M.. Stevens. Nancy J.. Roberts. Eric M.. 2014-07-29. The basal titanosaurianRukwatitan bisepultus(Dinosauria, Sauropoda) from the middle Cretaceous Galula Formation, Rukwa Rift Basin, southwestern Tanzania. Journal of Vertebrate Paleontology. 34. 5. 1133–1154. 10.1080/02724634.2014.845568. 2014JVPal..34.1133G . 677002 . 0272-4634.
  7. Gorscak. Eric. O'Connor. Patrick M.. Roberts. Eric M.. Stevens. Nancy J.. 2017-07-04. The second titanosaurian (Dinosauria: Sauropoda) from the middle Cretaceous Galula Formation, southwestern Tanzania, with remarks on African titanosaurian diversity. Journal of Vertebrate Paleontology. 37. 4. e1343250. 10.1080/02724634.2017.1343250. 2017JVPal..37E3250G . 90885040 . 0272-4634.
  8. O’Connor. Patrick M.. Gottfried. Michael D.. Stevens. Nancy J.. Roberts. Eric M.. Ngasala. Sifa. Kapilima. Saidi. Chami. Remigius. March 2006. A new vertebrate fauna from the Cretaceous Red Sandstone Group, Rukwa Rift Basin, Southwestern Tanzania. Journal of African Earth Sciences. 44. 3. 277–288. 10.1016/j.jafrearsci.2005.11.022. 2006JAfES..44..277O . 1464-343X.
  9. OConnor. Patrick. Krause. David. Stevens. Nancy. MacPhee. Ross. Groenke. Joseph. Kalthoff. Daniela. 2019. A new mammal from the Upper Cretaceous (Turonian–Campanian) Galula Formation, southwestern Tanzania. Acta Palaeontologica Polonica. 64. 10.4202/app.00568.2018. free.
  10. KRAUSE. DAVID W.. GOTTFRIED. MICHAEL D.. O’CONNOR. PATRICK M. ROBERTS. ERIC M.. 2003. A Cretaceous mammal from Tanzania. Acta Palaeontologica Polonica. 48. 3. 321–330.