Lefipán Formation
The Lefipán Formation is a Maastrichtian to Danian, straddling the Cretaceous-Paleogene boundary, geologic formation of the Cañadón Asfalto Basin in Chubut Province, Patagonia, Argentina. The up to thick stratigraphic unit comprises mudstones, sandstones, siltstones and conglomerates, sourced from the North Patagonian Massif and deposited in a deltaic to shallow marine environment with a strong tidal influence. The basin that in those times was connected to the widening South Atlantic Ocean with a seaway connection to the Austral Basin and possibly with the Pacific Ocean.

The formation has provided unique fossil flora assemblages dating to the Cretaceous and Paleogene ages, and are characteristic of the early Cenozoic after the extinction of the dinosaurs. The occurrence of the same taxa in the Maastrichtian and Danian successions suggests that the Cretaceous-Paleogene extinction event did not affect aquatic plant communities, which retained approximately similar structure and composition during the transition between the latest Maastrichtian and the earliest Paleocene. Insect predation on fossil leaves shows a considerably more rapid recovery from the extinction in event in Patagonia (about 4 Ma) than in the Western Interior of North America, estimated at 9 million years.

Fossils of the mammal "Cocatherium", the oldest known marsupial or any therian mammal in the Southern Hemisphere, and fish; "Hypolophodon patagoniensis" and shark teeth were found in the Danian section of the formation. The Danian part of the succession contains fossil flora of Lactoridaceae, presently a monotypic family restricted to the subtropical forests of the Juan Fernández Archipelago in the South Pacific Ocean, offshore Chile. The latest Cretaceous lower section of the formation contains fossils of a plesiosaur; "Aristonectes parvidens". The genus "Lefipania padillae" and species "Cocatherium lefipanum" and "Araucaria lefipanensis" were named after the formation.
Q278141
Maastrichtian
TIME
Q502179
Danian
TIME
Q682871
Cretaceous-Paleogene boundary
LOC
Q736917
formation
Concept
Q65047273
Cañadón Asfalto Basin
UNK
Q45007
Chubut Province
LOC
Q1507
Patagonia
LOC
Q414
Argentina
LOC
Q6642424
mudstone
Concept
Q13085
sandstone
Concept
Q565731
siltstone
Concept
Q191704
conglomerates
Concept
Q25100930
North Patagonian Massif
UNK
Q43197
deltaic
Concept
Q1994702
environment
UNK
Q23384
tidal
Concept
None
South Atlantic Ocean
UNK
Q6729639
Austral Basin
LOC
Q98
Pacific Ocean
LOC
Q21998075
Cocatherium
Concept
None
Hypolophodon patagoniensis
UNK
Q626192
shark teeth
Concept
Q131659
Lactoridaceae
Concept
Q310890
monotypic
Concept
Q156325
Juan Fernández Archipelago
LOC
Q98
South Pacific Ocean
LOC
Q44626
Cretaceous
TIME
Q269195
plesiosaur
Concept
Q2154474
Aristonectes parvidens
Concept
None
Lefipania padillae
UNK
Q21998075
Cocatherium lefipanum
Concept
None
Araucaria lefipanensis
UNK
Q85776182
Lefipán Formation
UNK
+4^^http://www.w3.org/2001/XMLSchema#decimal
4
NUMBER
+9^^http://www.w3.org/2001/XMLSchema#decimal
9
NUMBER
country
located in the administrative territorial entity
located in or next to body of water