The Quebrada del Barro Formation formed within a
rift basin during a period of renewed fracturing. It encompasses 600 to 1,400 metres (2,000 to 4,600 ft) of red
sandstones, fine
conglomerates, and
diamictites.[3] Early hypotheses on the depositional environment proposed that the sediments formed in an
alluvial fan or
braided river system, while a newer proposal outlines how four different
facies within the formation can be used to reconstruct a meandering
semiarid floodplain deposited by
mudflows and discharging in
heterolithicterminal splays.[6]
Fossil content
The fauna of Quebrada del Barro is similar to that of the neighboring
Los Colorados Formation which is considered to be from the
Norian stage of the Late Triassic.[7] Both formations preserve fossils from groups such as
sauropodomorphdinosaurs,
cynodonts, and
testudinatans. However, Quebrada del Barro is more abundant in
sphenodontians (Sphenotitan),
tritheledontid cynodonts, and
coelophysoid dinosaurs (Lucianovenator), while sauropodomorphs are somewhat less common and
aetosaurs are completely absent, in contrast to the Los Colorados Formation.[3] Sphenodontians and cynodonts are also abundant in microfossil assemblages.[6] In addition, the Quebrada del Barro Formation preserves some of the only
pterosaur and Dromomeron specimens known from Triassic strata in Argentina. Although the sphenodontian and cynodont-dominated fauna of Quebrada del Barro is akin to that of the Faxinal del Sotorno assemblage of the
BrazilianCaturrita Formation, the fauna of the Faxinal del Sotorno assemblage is otherwise indicative of an older part of the Triassic than the Quebrada del Barro Formation.[3]
^Weishampel, David B; et al. (2004). "Dinosaur distribution (Late Triassic, South America)." In: Weishampel, David B.; Dodson, Peter; and Osmólska, Halszka (eds.): The Dinosauria, 2nd, Berkeley: University of California Press. Pp. 527–528.
ISBN0-520-24209-2.
^Ricardo N. Martínez; Cecilia Apaldetti (2017). "A late Norian-Rhaetian coelophysid neotheropod (Dinosauria, Saurischia) from the Quebrada del Barro Formation, northwestern Argentina". Ameghiniana. in press.
doi:10.5710/AMGH.09.04.2017.3065.
^"Riojasaurus." In: Dodson, Peter & Britt, Brooks & Carpenter, Kenneth & Forster, Catherine A. & Gillette, David D. & Norell, Mark A. & Olshevsky, George & Parrish, J. Michael & Weishampel, David B. The Age of Dinosaurs. Publications International, LTD. p. 41.
ISBN0-7853-0443-6.
^Ricardo N. Martínez; Cecilia Apaldetti; Gustavo A. Correa; Diego Abelín (2016). "A Norian lagerpetid dinosauromorph from the Quebrada del Barro Formation, northwestern Argentina". Ameghiniana. 53 (1): 1–13.
doi:
10.5710/AMGH.21.06.2015.2894.
S2CID131613066.
The Quebrada del Barro Formation formed within a
rift basin during a period of renewed fracturing. It encompasses 600 to 1,400 metres (2,000 to 4,600 ft) of red
sandstones, fine
conglomerates, and
diamictites.[3] Early hypotheses on the depositional environment proposed that the sediments formed in an
alluvial fan or
braided river system, while a newer proposal outlines how four different
facies within the formation can be used to reconstruct a meandering
semiarid floodplain deposited by
mudflows and discharging in
heterolithicterminal splays.[6]
Fossil content
The fauna of Quebrada del Barro is similar to that of the neighboring
Los Colorados Formation which is considered to be from the
Norian stage of the Late Triassic.[7] Both formations preserve fossils from groups such as
sauropodomorphdinosaurs,
cynodonts, and
testudinatans. However, Quebrada del Barro is more abundant in
sphenodontians (Sphenotitan),
tritheledontid cynodonts, and
coelophysoid dinosaurs (Lucianovenator), while sauropodomorphs are somewhat less common and
aetosaurs are completely absent, in contrast to the Los Colorados Formation.[3] Sphenodontians and cynodonts are also abundant in microfossil assemblages.[6] In addition, the Quebrada del Barro Formation preserves some of the only
pterosaur and Dromomeron specimens known from Triassic strata in Argentina. Although the sphenodontian and cynodont-dominated fauna of Quebrada del Barro is akin to that of the Faxinal del Sotorno assemblage of the
BrazilianCaturrita Formation, the fauna of the Faxinal del Sotorno assemblage is otherwise indicative of an older part of the Triassic than the Quebrada del Barro Formation.[3]
^Weishampel, David B; et al. (2004). "Dinosaur distribution (Late Triassic, South America)." In: Weishampel, David B.; Dodson, Peter; and Osmólska, Halszka (eds.): The Dinosauria, 2nd, Berkeley: University of California Press. Pp. 527–528.
ISBN0-520-24209-2.
^Ricardo N. Martínez; Cecilia Apaldetti (2017). "A late Norian-Rhaetian coelophysid neotheropod (Dinosauria, Saurischia) from the Quebrada del Barro Formation, northwestern Argentina". Ameghiniana. in press.
doi:10.5710/AMGH.09.04.2017.3065.
^"Riojasaurus." In: Dodson, Peter & Britt, Brooks & Carpenter, Kenneth & Forster, Catherine A. & Gillette, David D. & Norell, Mark A. & Olshevsky, George & Parrish, J. Michael & Weishampel, David B. The Age of Dinosaurs. Publications International, LTD. p. 41.
ISBN0-7853-0443-6.
^Ricardo N. Martínez; Cecilia Apaldetti; Gustavo A. Correa; Diego Abelín (2016). "A Norian lagerpetid dinosauromorph from the Quebrada del Barro Formation, northwestern Argentina". Ameghiniana. 53 (1): 1–13.
doi:
10.5710/AMGH.21.06.2015.2894.
S2CID131613066.