Los Rastros Formation

Los Rastros Formation
Los Rastros Formation
Stratigraphic range: Carnian; 234.91–234.03 Ma PreꞒ Ꞓ O S D C P T J K Pg N ↓
Type	Geological formation
Unit of	Agua de la Peña Group
Underlies	Ischigualasto Formation
Overlies	Ischichuca Formation
Thickness	Up to 1,000 m (3,300 ft)
Lithology
Primary	Claystone, sandstone
Other	Mudstone
Location
Coordinates	29°06′S 69°06′W / 29.1°S 69.1°W
Approximate paleocoordinates	45°48′S 34°54′W / 45.8°S 34.9°W
Region	La Rioja & San Juan Provinces
Country	Argentina
Extent	Ischigualasto-Villa Unión Basin
	Los Rastros Formation (Argentina)

The Los Rastros Formation is a Ladinian to Carnian fossiliferous formation of the Agua de la Peña Group in the Ischigualasto-Villa Unión Basin in northwestern Argentina. Fossil theropod tracks,^[1] as well as many insects, fossil fish of Myriolepis,^[2] bivalves and crustaceans and flora have been reported from the formation.

Description

The formation overlies the Ischicuca Formation and is overlain by the Ischigualasto Formation.^[3] The formation belongs to the Agua de la Peña Group of the Ischigualasto-Villa Unión Basin, where it is exposed in the Ischigualasto Provincial Park, a World Heritage site in Argentina.^[4] The up to 1,000 metres (3,300 ft) thick formation of claystones, mudstones and sandstones was deposited in a deltaic to lacustrine environment during the first post-rift sequence in the basin.^[3]^[5]

A CA-TIMS U-Pb zircon age of 234.47 ± 0.44 Ma from the lower Los Rastros Formation was published in 2020. The acquired age demonstrates that most of the overlying lacustrine strata within the basin were deposited during or after the Carnian Pluvial Event (CPE) that lasted from 237 to 227 Ma approximately.^[6]

Fossil content

The following fossils among others have been recovered from the formation:^[5]

Fish

Myriolepis sp.^[2]

Insects

Argentinoblatta herbsti^[7]
Argentinoblattula revelata^[8]
Argentinocupes pulcher
Argentinosyne bonapartei
Babuskaya elaterata
Condorblatta lutzae^[7]
Hermosablatta crassatella, H. pectinata^[9]
Ischichucasyne cladocosta
Lariojablatta chanarensis^[10]
Mancusoblatta pulchella^[11]
Miomina riojana
Pulchellablatta nana^[12]
Saaloscytina carmonae
Samaroblatta corrientesina^[12]
S. gualoensis^[13]
Triassoblatta argentina^[10]

Crustaceans

Lioestheria sp.^[2]

Bivalves

Paleomutella sp.^[2]

Flora

Ichnofossils

References

^ Weishampel et al., 2004, pp. 517-607
^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k Leonardi, 1994, p.20
^ ^a ^b Aceituno Cieri, 2015, p.60
^ Kent et al, 2014, p.7959
^ ^a ^b Los Chañares at Fossilworks.org
^ Mancuso et al., 2020
^ ^a ^b Martins Neto et al., 2005, p.5
^ Martins Neto et al., 2005, p.16
^ Martins Neto et al., 2005, p.10
^ ^a ^b Martins Neto et al., 2005, p.12
^ Martins Neto et al., 2005, p.8
^ ^a ^b Martins Neto et al., 2005, p.14
^ Martins Neto et al., 2005, p.13
^ Leonardi, 1994, p.21

Bibliography

[dinosaurdistribution-1] Weishampel et al., 2004, pp. 517-607

[Leonardi1994_p20-2] ^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k Leonardi, 1994, p.20

[Aceituno2015_p60-3] Aceituno Cieri, 2015, p.60

[Kent2014_p7959-4] Kent et al, 2014, p.7959

[LosChanares-5] Los Chañares at Fossilworks.org

[Mancuso2020-6] Mancuso et al., 2020

[Martins2005_p5-7] Martins Neto et al., 2005, p.5

[Martins2005_p16-8] Martins Neto et al., 2005, p.16

[Martins2005_p10-9] Martins Neto et al., 2005, p.10

[Martins2005_p12-10] Martins Neto et al., 2005, p.12

[Martins2005_p8-11] Martins Neto et al., 2005, p.8

[Martins2005_p14-12] Martins Neto et al., 2005, p.14

[Martins2005_p13-13] Martins Neto et al., 2005, p.13

[Leonardi1994_p21-14] Leonardi, 1994, p.21

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Description

Fossil content

See also

References

Bibliography