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The La Colonia Formation is a geological
formation
Formation may refer to:
Linguistics
* Back-formation, the process of creating a new lexeme by removing or affixes
* Word formation, the creation of a new word by adding affixes
Mathematics and science
* Cave formation or speleothem, a secondar ...
in
Argentina
Argentina (), officially the Argentine Republic ( es, link=no, República Argentina), is a country in the southern half of South America. Argentina covers an area of , making it the second-largest country in South America after Brazil, th ...
whose strata date back to the
Late Cretaceous
The Late Cretaceous (100.5–66 Ma) is the younger of two epochs into which the Cretaceous Period is divided in the geologic time scale. Rock strata from this epoch form the Upper Cretaceous Series. The Cretaceous is named after ''creta'', the ...
. Dinosaur remains are among the fossils that have been recovered from the formation.
[Weishampel et al., 2004, pp.600-604]
Originally thought to be
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 ...
(c.73-72 million years ago) in age or earlier, studies of underlying formations have made a
Maastrichtian
The Maastrichtian () is, in the ICS geologic timescale, the latest age (uppermost stage) of the Late Cretaceous Epoch or Upper Cretaceous Series, the Cretaceous Period or System, and of the Mesozoic Era or Erathem. It spanned the interval from ...
(70–66 million years ago) age more likely.
[Rauhut, 2003]
It is divided up into three distinct facies, the first is up to thick and consists of
conglomerate, the second is by far the thickest at over , consists of
siltstone
Siltstone, also known as aleurolite, is a clastic sedimentary rock that is composed mostly of silt. It is a form of mudrock with a low clay mineral content, which can be distinguished from shale by its lack of fissility.Blatt ''et al.'' 1980, p ...
and
claystone
Mudrocks are a class of fine-grained siliciclastic sedimentary rocks. The varying types of mudrocks include siltstone, claystone, mudstone, slate, and shale. Most of the particles of which the stone is composed are less than and are too sm ...
, with interbeds of claystone/shale and
sandstone
Sandstone is a clastic sedimentary rock composed mainly of sand-sized (0.0625 to 2 mm) silicate grains. Sandstones comprise about 20–25% of all sedimentary rocks.
Most sandstone is composed of quartz or feldspar (both silicates) ...
, the third is less than thick and consists of clay, and probably represents a nearshore marine
environment
Environment most often refers to:
__NOTOC__
* Natural environment, all living and non-living things occurring naturally
* Biophysical environment, the physical and biological factors along with their chemical interactions that affect an organism or ...
.
[Gasparini et al., 2015]
Flora
The paleoflora was known for its aquatic components, ''Paleoazolla'' and ''Regnellidium''.
However, recent paleobotanical discoveries at the Cañadón del Irupé locality have revealed the presence of a more diverse range of plants associated with these water bodies, including
pteridophytes
A pteridophyte is a vascular plant (with xylem and phloem) that disperses spores. Because pteridophytes produce neither flowers nor seeds, they are sometimes referred to as "cryptogams", meaning that their means of reproduction is hidden. Ferns, ...
,
gymnosperms
The gymnosperms ( lit. revealed seeds) are a group of seed-producing plants that includes conifers, cycads, ''Ginkgo'', and gnetophytes, forming the clade Gymnospermae. The term ''gymnosperm'' comes from the composite word in el, Î³Ï…Î¼Î½ÏŒÏ ...
, and various
angiosperms
Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (), commonly called angiosperms. The term "angiosperm" is derived from the Greek words ('container, vessel') and ('seed'), and refers to those plants th ...
.
Among these are fossil leaves and fruits assignable to
Nelumbonaceae
Nelumbonaceae is a family of aquatic flowering plants. ''Nelumbo'' is the sole extant genus, containing ''Nelumbo lutea'', native to North America, and ''Nelumbo nucifera'', widespread in Asia. At least four other genera, ''Nelumbites'', ''Exne ...
.
[Gandolfo & Cúneo, 2005]
Fossil content
Turtles
Plesiosaurs
Mammals
Over 300 mammal specimens have been found in the La Colonia Formation.
[Rougier et al., 2009, p.225]
Dinosaurs
See also
*
List of dinosaur-bearing rock formations
This list of dinosaur-bearing rock formations is a list of geologic formations in which dinosaur fossils have been documented.
Containing body fossils
* List of stratigraphic units with dinosaur body fossils
** List of stratigraphic units with few ...
*
Allen Formation
The Allen Formation is a geological formation in Argentina whose strata date back to the Late Cretaceous (middle Campanian to early Maastrichtian.Salgado et al., 2007 Dinosaur remains are among the fossils that have been recovered from the formati ...
, Campanian to Maastrichtian fossiliferous formation of the
Neuquén Basin
Neuquén Basin ( es, Cuenca Neuquina) is a sedimentary basin covering most of Neuquén Province in Argentina. The basin originated in the Jurassic and developed through alternating continental and marine conditions well into the Tertiary. The bas ...
*
Angostura Colorada Formation, Campanian to Maastrichtian fossiliferous formation of the
North Patagonian Massif
The North Patagonian Massif or Somún Cura Massif (Spanish language, Spanish: ''Macizo Norpatagónico'', ''Macizo Nordpatagónico'' or ''Macizo de Somún Cura'') is a massif in northern Patagonia located in the Argentine provinces of RÃo Negro Pro ...
*
Colorado Formation, Campanian to Maastrichtian fossiliferous formation of the
Colorado Basin
*
Lago Colhué Huapà Formation
The Lago Colhué Huapà Formation is a Late Cretaceous geologic formation of the Chubut Group in the Golfo San Jorge Basin in Patagonia, Argentina. The formation, named after Lake Colhué HuapÃ, is overlain by the Salamanca Formation of the R ...
, Campanian to Maastrichtian fossiliferous formation of the
Golfo San Jorge Basin
The Golfo San Jorge Basin ( es, Cuenca del Golfo San Jorge) is a hydrocarbon-rich sedimentary basin located in eastern Patagonia, Argentina. The basin covers the entire San Jorge Gulf and an inland area west of it, having one half located in Santa ...
References
Bibliography
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* {{ISBN, 0-520-24209-2
Further reading
* A. M. Albino. 2000. New record of snakes from the Cretaceous of Patagonia (Argentina). Geodiversitas 22(2):247-253
* N. R. Cúneo, E. J. Hermsen, and M. A. Gandolfo. 2013. ''Regnellidium'' (Salviniales, Marsileaceae) macrofossils and associated spores from the Late Cretaceous of South America. PloSOne 174(3):340-349
* J. P. O'Gorman, L. Salgado, I. A. Cerda and Z. Gasparini. 2013. First record of gastroliths associated with elasmosaur remains from La Colonia Formation (Campanian–Maastrichtian), Chubut, Patagonia Argentina, with comments on the probable depositional palaeoenvironment of the source of the gastroliths. Cretaceous Research 40:212-217
* J. O'Gorman and Z. Gasparini. 2013. Revision of Sulcusuchus erraini (Sauropterygia, Polycotylidae) from the Upper Cretaceous of Patagonia, Argentina. Alcheringa 37(2):163-176
* T. Harper, A. Parras, and G. W. Rougier. 2018. ''Reigitherium'' (Meridiolestida, Mesungulatoidea) an Enigmatic Late Cretaceous Mammal from Patagonia, Argentina: Morphology, Affinities, and Dental Evolution. Journal of Mammalian Evolution
* Z. Kielan-Jaworowska, E. Ortiz-Jaureguizar, C. Vieytes, R. Pascual, and F. J. Goin. 2007. First cimolodontan multituberculate mammal from South America. Acta Palaeontologica Polonica 52(2):257-262
Geologic formations of Argentina
Upper Cretaceous Series of South America
Cretaceous Argentina
Maastrichtian Stage of South America
Sandstone formations
Shale formations
Siltstone formations
Conglomerate formations
Tidal deposits
Formations
Fossiliferous stratigraphic units of South America
Paleontology in Argentina
Geology of Chubut Province
Geology of Patagonia