The Galula Formation is a

geological formation A geological formation, or simply formation, is a body of rock having a consistent set of physical characteristics ( lithology) that distinguishes it from adjacent bodies of rock, and which occupies a particular position in the layers of rock exp ...

located south of

Lake Rukwa Lake Rukwa is an endorheic lake located the Rukwa Valley of Rukwa Region, Songwe Region and Katavi Region in southwestern Tanzania. The lake is the third largest inland body of water in the country. Geography The alkaline Lake Rukwa lies midw ...

Tanzania Tanzania (; ), officially the United Republic of Tanzania ( sw, Jamhuri ya Muungano wa Tanzania), is a country in East Africa within the African Great Lakes region. It borders Uganda to the north; Kenya to the northeast; Comoro Islands and ...

, part of the Red Sandstone Group of the Rukwa Rift Basin. Along with the unconformably overlying

Oligocene The Oligocene ( ) is a geologic epoch of the Paleogene Period and extends from about 33.9 million to 23 million years before the present ( to ). As with other older geologic periods, the rock beds that define the epoch are well identified but the ...

Nsungwe Formation The Nsungwe Formation is a formation in the Rukwa Rift Basin of the East African Rift System, it is Oligocene in age based on U-Pb dating of a tuff horizon within the formation. It is part of the Red Sandstone Group along with the uncomfortably ...

. It is divided into two members, the lower Mtuka Member and the upper Namba Member. The age of the deposit is poorly constrained, with the Mtuka Member likely being

Aptian The Aptian is an age in the geologic timescale or a stage in the stratigraphic column. It is a subdivision of the Early or Lower Cretaceous Epoch or Series and encompasses the time from 121.4 ± 1.0 Ma to 113.0 ± 1.0 Ma (million years ago), a ...

Cenomanian The Cenomanian is, in the ICS' geological timescale, the oldest or earliest age of the Late Cretaceous Epoch or the lowest stage of the Upper Cretaceous Series. An age is a unit of geochronology; it is a unit of time; the stage is a unit in the s ...

in age, while the Namba Member being Cenomanian to

Campanian The Campanian is the fifth of six ages of the Late Cretaceous Epoch on the geologic timescale of the International Commission on Stratigraphy (ICS). In chronostratigraphy, it is the fifth of six stages in the Upper Cretaceous Series. Campanian s ...

in age based on

Geomagnetic reversal A geomagnetic reversal is a change in a planet's magnetic field such that the positions of magnetic north and magnetic south are interchanged (not to be confused with geographic north and geographic south). The Earth's field has alternated ...

s. It is correlated with the

Dinosaur Beds The Dinosaur Beds is a geological formation in Malawi whose strata date back to the Early Cretaceous. The age of the deposit is poorly constrained, but is likely to date from the Barremian to Aptian. Dinosaurs, turtles and crocodyliomorphs remain ...

Malawi Malawi (; or aláwi Tumbuka: ''Malaŵi''), officially the Republic of Malawi, is a landlocked country in Southeastern Africa that was formerly known as Nyasaland. It is bordered by Zambia to the west, Tanzania to the north and northeast ...

. 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 Clastic rocks are composed of fragments, or clasts, of pre-existing minerals and rock. A clast is a fragment of geological detritus,Essentials of Geology, 3rd Ed, Stephen Marshak, p. G-3 chunks, and smaller grains of rock broken off other rocks ...

, thicker and a greater frequency of

overbank An overbank is an alluvial geological deposit consisting of sediment that has been deposited on the floodplain of a river or stream by flood waters that have broken through or overtopped the banks. The sediment is carried in suspension, and be ...

siltstone and mudstone

lenses A lens is a transmissive optical device which focuses or disperses a light beam by means of refraction. A simple lens consists of a single piece of transparent material, while a compound lens consists of several simple lenses (''elements''), ...

and a higher proportion of

paleosol In the geosciences, paleosol (''palaeosol'' in Great Britain and Australia) is an ancient soil that formed in the past. The precise definition of the term in geology and paleontology is slightly different from its use in soil science. In geolo ...

s. 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

Crocodyliformes

Dinosaurs

Turtles

Mammals

References

{{reflist Geologic formations of Tanzania Albian Stage Aptian Stage Lower Cretaceous Series of Africa Cenomanian Stage Turonian Stage Coniacian Stage Santonian Stage Campanian Stage Upper Cretaceous Series of Africa Cretaceous Tanzania Sandstone formations Fluvial deposits Paleontology in Tanzania