Los Molles Formation

Los Molles Formation
Stratigraphic range: Pliensbachian-Callovian ~185–165 Ma PreꞒ Ꞓ O S D C P T J K Pg N
Type	Geological formation
Unit of	Cuyo Group
Underlies	Niyeu–Lajas Formation
Overlies	Lajoa Formation
Lithology
Primary	Organic shale
Other	Lime-mudstone
Location
Coordinates	39°10′18″S 69°39′35″W
Approximate paleocoordinates	36.9°S 31.1°W / -36.9; -31.1
Region	Mendoza Province Neuquén Province
Country	Argentina
Extent	Neuquén Basin
Type section
Country	Argentina
Los Molles Formation (Argentina)

The Los Molles Formation is a geologic formation of Early to Middle Jurassic age, located at northern and central part of Neuquén Basin at Mendoza Shelf in Argentina. It is overlain by the Niyeu–Lajas Formation.^[1]

Description

Outcrop map of the formation

It is the second largest oil and gas formation in the Neuquén Basin after the Vaca Muerta. Los Molles Formation is estimated to have 275 trillion cubic feet (7.8×10^¹² m³) of technically recoverable shale gas and 3.7 billion barrels (590,000,000 m³) of technically recoverable oil.^[2] In July 2015, the Buenos Aires Herald indicated that Pan American Energy and YPF planned to drill 46 shale gas wells in Los Molles over the next four years in their Lindero Atravesado drilling block, at an estimated cost of US$590 million.^[3]

Fossil content

Color key Taxon Reclassified taxon Taxon falsely reported as present Dubious taxon or junior synonym Ichnotaxon Ootaxon Morphotaxon		Notes Uncertain or tentative taxa are in small text; crossed out taxa are discredited.

Dinosaurs

Ornithischians

Ornithischians of the Los Molles Formation
Genus	Species	Location	Stratigraphic position	Material	Notes	Images
Isaberrysaura[4]	I. mollensis				A stegosaurian ornithischian

Crocodylomorphs

Crocodylomorphs of the Los Molles Formation
Genus	Species	Location	Stratigraphic position	Material	Notes	Images
Metriorhynchidae Indet.[5]	Indeterminate

Ichthyosaurs

Ichthyosaurs of the Los Molles Formation
Genus	Species	Location	Stratigraphic position	Material	Notes	Images
Chacaicosaurus[6]	C. cayi				A neoichthyosaurian ichthyosaur
Mollesaurus[7]	M. periallus				A ophthalmosaurine ophthalmosaurid

Plesiosaurs

Plesiosaurs of the Los Molles Formation
Genus	Species	Location	Stratigraphic position	Material	Notes	Images
Maresaurus[8]	M. coccai				A rhomaleosaurid plesiosaur

Molluscs

Cephalopods

Cephalopods of the Los Molles Formation
Genus	Species	Location	Stratigraphic position	Material	Notes	Images
Costiphylloceras[9]	C. limayense				A phylloceratid ammonite
Pseudosonninia[10]	P. chacaymelehuensis				A oppeliid ammonite

See also

• Vaca Muerta
• List of dinosaur bearing rock formations
• Toarcian turnover
• Toarcian formations
  • Marne di Monte Serrone, Italy
  • Calcare di Sogno, Italy
  • El Pedregal Formation, Spain
  • Sachrang Formation, Austria
  • Posidonia Shale, Lagerstätte in Germany
  • Ciechocinek Formation, Germany and Poland
  • Krempachy Marl Formation, Poland and Slovakia
  • Lava Formation, Lithuania
  • Azilal Group, North Africa
  • Whitby Mudstone, England
  • Fernie Formation, Alberta and British Columbia
    • Poker Chip Shale
  • Whiteaves Formation, British Columbia
  • Navajo Sandstone, Utah
  • Mawson Formation, Antarctica
  • Kandreho Formation, Madagascar
  • Kota Formation, India
  • Cattamarra Coal Measures, Australia

References

1. McIlroy et al., 2005
2. EIA, 2013
3. Shale fields to get US$14 billion boost
4. Leonardo Salgado; José I. Canudo; Alberto C. Garrido; Miguel Moreno-Azanza; Leandro C. A. Martínez; Rodolfo A. Coria; José M. Gasca (2017). "A new primitive Neornithischian dinosaur from the Jurassic of Patagonia with gut contents". Scientific Reports. 7: Article number 42778. Bibcode:2017NatSR...742778S. doi:10.1038/srep42778. PMC 5311864. PMID 28202910.
5. Herrera, L. Y. (2015). "Metriorhynchidae (Crocodylomorpha: Thalattosuchia) from Upper Jurassic–Lower Cretaceous of Neuquén Basin (Argentina), with comments on the natural casts of the brain". Publicación Electrónica de la Asociación Paleontológica Argentina. 15 (1): 159–171. doi:10.5710/PEAPA.09.06.2015.104. hdl:11336/54082.
6. Fernández, M. S. (1994). "A new long-snouted ichthyosaur from the Early Bajocian of Neuquén Basin, Argentina". Ameghiniana. 31 (3): 291–297.
7. Fernández, Marta S. (1999). "A new ichthyosaur from the Los Molles Formation (Early Bajocian), Neuquen Basin, Argentina". Journal of Paleontology. 73 (4): 677–681. Bibcode:1999JPal...73..677F. doi:10.1017/S0022336000032492. JSTOR 1306766. S2CID 130751356.
8. Smith, A. S.; Dyke, G. J. (2008). "The skull of the giant predatory pliosaur Rhomaleosaurus cramptoni: Implications for plesiosaur phylogenetics" (PDF). Naturwissenschaften. 95 (10): 975–980. Bibcode:2008NW.....95..975S. doi:10.1007/s00114-008-0402-z. PMID 18523747. S2CID 12528732.
9. Joly, B.; Parent, H.; Garrido, A. C. (2023). "Aalenian phylloceratid ammonites from Picún Leufú, Neuquén Basin, Argentina". Revue de Paléobiologie, Genève. 42 (1): 143–148. doi:10.5281/zenodo.7446073.
10. Horacio Parent; Alberto C. Garrido; Günter Schweigert; Luciano Brambilla (2019). "Pseudosonninia, a new genus of oppeliid ammonite (Haploceratoidea) from the Callovian (Middle Jurassic) of the Neuquén Basin, Argentina". Volumina Jurassica. 17: 39–48. Archived from the original on 2019-09-26. Retrieved 2019-09-26.

Bibliography

• McIlroy, Duncan; Flint, Stephen; Howell, John A.; Timms, Nick (2005), The Neuquén Basin, Argentina: A Case Study in Sequence Stratigraphy and Basin Dynamics - Sedimentology of the tide-dominated Jurassic Lajas Formation, Neuquén Basin, Argentina, Geological Society of London, p. 84, ISBN 9781862391901, retrieved 2019-02-16
• Salgado, Leonardo; Canudo, José I.; Garrido, Alberto C.; Moreno Azanza, Miguel; Martínez, Leandro C. A.; Coria, Rodolfo A.; Gasca, José M. (2017), "A new primitive Neornithischian dinosaur from the Jurassic of Patagonia with gut contents", Scientific Reports, 7: 42778, Bibcode:2017NatSR...742778S, doi:10.1038/srep42778, PMC 5311864, PMID 28202910, retrieved 2019-02-16
• Various, Authors (2013), Technically Recoverable Shale Oil and Shale Gas Resources: An Assessment of 137 Shale Formations in 41 Countries Outside the United States (PDF), U.S. Energy Information Administration (EIA), pp. _, retrieved 2013-06-11