The Ambolafotsy Formation is a Turonian aged geological formation in the Diego Basin of Antsiranana Province in Madagascar. It is a mostly terrestrial unit deposited during a marine regression close to the shoreline. The dinosaur ''Dahalokely'' has been discovered in the formation.

Description

The section containing the Dahalokely site is informally termed the "Ambolafotsy Formation" and is divided into lower, middle (containing the type locality), and upper units. The lower unit has produced several biostratigraphically informative foraminifera, including ''Whiteinella, Whiteinella aprica'', ''W. baltica'', ''Helvetoglobotruncana, Helvetoglobotruncana praehelvetica'', and ''H. helvetica'', and the nannofossil ''Quadrum, Quadrum gartneri'', placing the sample within the ''Q. gartneri'' and ''H. helvetica'' zones. The upper unit contains the ammonite ''Subprionocyclus, Subprionocyclus neptuni''. The sediments of most of the middle unit of the Ambolafotsy Formation are interpreted as terrestrial, deposited during a marine regression. Carbonized plant fragments are quite common in the middle unit, along with claystones, shales, and cross-bedded sandstones. Marine microfossils and macrofossils are generally absent, although a deposit of ostreids several meters above the type locality for ''Dahalokely'' suggests that the area was deposited close to the shoreline.Near Ampandriambengy, around the area of Antsiranana
at Fossilworks.org

References

{{reflist Geologic formations of Madagascar Cretaceous Madagascar Paleontology in Madagascar Upper Cretaceous Series of Africa Turonian Stage Shale formations Sandstone formations Antsiranana Province, Formations

Description

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References