Yacoraite Formation
Encyclopedia
The Yacoraite Formation is a largely Mesozoic
geologic formation. The deposits of this formation mainly date from the Maastrichtian
of the Upper Cretaceous
, but the K–T boundary
runs right through this formation near its top, and the uppermost parts are consequently from the Danian
(Lower Paleocene
). It was probably deposited around the intertidal zone
, as the sedimentary rock
s of this formation alternate according to sea level
changes between deposits of muddy beaches and of shallow ocean.
Dinosaur
remains are among the fossils that have been recovered from the formation, although none have yet been referred to a specific genus
.
Well-preserved dinosaur footprints – possibly of Hadrosauridae – have been found in this formation, as were fossil eggs, stromatolite
s and the Mesozoic palynomorph
Aquilapollenites.
Mesozoic
The Mesozoic era is an interval of geological time from about 250 million years ago to about 65 million years ago. It is often referred to as the age of reptiles because reptiles, namely dinosaurs, were the dominant terrestrial and marine vertebrates of the time...
geologic formation. The deposits of this formation mainly date from the Maastrichtian
Maastrichtian
The Maastrichtian is, in the ICS' geologic timescale, the latest age or upper stage of the Late Cretaceous epoch or Upper Cretaceous series, the Cretaceous period or system, and of the Mesozoic era or erathem. It spanned from 70.6 ± 0.6 Ma to 65.5 ± 0.3 Ma...
of the Upper Cretaceous
Cretaceous
The Cretaceous , derived from the Latin "creta" , usually abbreviated K for its German translation Kreide , is a geologic period and system from circa to million years ago. In the geologic timescale, the Cretaceous follows the Jurassic period and is followed by the Paleogene period of the...
, but the K–T boundary
K–T boundary
The K–T boundary is a geological signature, usually a thin band, dated to 65.5 ± 0.3 Ma ago. K is the traditional abbreviation for the Cretaceous period, and T is the abbreviation for the Tertiary period...
runs right through this formation near its top, and the uppermost parts are consequently from the Danian
Danian
The Danian is the oldest age or lowermost stage of the Paleocene epoch or series, the Paleogene period or system and the Cenozoic era or erathem. The beginning of the Danian age is at the Cretaceous-Tertiary extinction event...
(Lower Paleocene
Paleocene
The Paleocene or Palaeocene, the "early recent", is a geologic epoch that lasted from about . It is the first epoch of the Palaeogene Period in the modern Cenozoic Era...
). It was probably deposited around the intertidal zone
Intertidal zone
The intertidal zone is the area that is above water at low tide and under water at high tide . This area can include many different types of habitats, with many types of animals like starfish, sea urchins, and some species of coral...
, as the sedimentary rock
Sedimentary rock
Sedimentary rock are types of rock that are formed by the deposition of material at the Earth's surface and within bodies of water. Sedimentation is the collective name for processes that cause mineral and/or organic particles to settle and accumulate or minerals to precipitate from a solution....
s of this formation alternate according to sea level
Sea level
Mean sea level is a measure of the average height of the ocean's surface ; used as a standard in reckoning land elevation...
changes between deposits of muddy beaches and of shallow ocean.
Dinosaur
Dinosaur
Dinosaurs are a diverse group of animals of the clade and superorder Dinosauria. They were the dominant terrestrial vertebrates for over 160 million years, from the late Triassic period until the end of the Cretaceous , when the Cretaceous–Paleogene extinction event led to the extinction of...
remains are among the fossils that have been recovered from the formation, although none have yet been referred to a specific genus
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
.
Well-preserved dinosaur footprints – possibly of Hadrosauridae – have been found in this formation, as were fossil eggs, stromatolite
Stromatolite
Stromatolites or stromatoliths are layered accretionary structures formed in shallow water by the trapping, binding and cementation of sedimentary grains by biofilms of microorganisms, especially cyanobacteria ....
s and the Mesozoic palynomorph
Palynomorph
Palynomorph is the geological term used to describe a particle of a size between five and 500 micrometres, found in rock deposits and composed of organic material such as chitin, pseudochitin and sporopollenin...
Aquilapollenites.