Pisco Formation Explained

Pisco Formation
Type:	Geological formation
Period:	Pliocene
Age:	Late Miocene-Early Pliocene (Tortonian-Zanclean)^[1] ~
Prilithology:	Tuffaceous sandstone, diatomaceous siltstone
Otherlithology:	Conglomerate, dolomite
Namedfor:	Pisco
Region:	Arequipa & Ica Regions
Coordinates:	-15.7°N -74.5°W
Paleocoordinates:	-15.8°N -73.8°W
Unitof:	Pisco Basin
Overlies:	Chilcatay & Caballas Formations
Thickness:	640m (2,100feet)
Extent:	From Pisco to Yauca

The Pisco Formation is a geologic formation located in Peru, on the southern coastal desert of Ica and Arequipa. The approximately 640m (2,100feet) thick formation was deposited in the Pisco Basin, spanning an age from the Late Miocene up to the Early Pliocene, roughly from 9.6 to 4.5 Ma. The tuffaceous sandstones, diatomaceous siltstones, conglomerates and dolomites were deposited in a lagoonal to near-shore environment, in bays similar to other Pacific South American formations as the Bahía Inglesa and Coquimbo Formations of Chile.

Several specialists consider the Pisco Formation one of the most important Lagerstätten,^{[2] [3]} based on the large amount of exceptionally preserved marine fossils, including sharks (most notably megalodon), penguins, whales, dolphins, birds, marine crocodiles and aquatic giant sloths.

Famous fossils found in these layers include the giant raptorial sperm whale Livyatan,^[4] the aquatic sloth Thalassocnus,^[5] the sperm whale Acrophyseter, and the walrus-like dolphin Odobenocetops.^[6]

Description

The Pisco Formation of the Pisco Basin consists of tuffaceous sandstones, diatomaceous yellow to gray siltstones and a basal conglomerate.^[7] The formation is deposited from Pisco in the north to Yauca in the south. The northern portion is known as the Ocucaje Area and the southern part as the Sacaco Area.^[8] The total thickness of the formation is estimated at 640m (2,100feet).^[9] The formation unconformably overlies the Chilcatay and Caballas Formations.

Paleobiota of the Pisco Formation

The Pisco Formation has provided a rich resource of marine fauna, including marine mammals like cetaceans and seals, large fishes, reptiles, and penguins.^[10] It is also one of the richest sites in the world for fossil cetaceans, with close to 500 examples being found in the formation.^[11]

The oldest fossils of the aquatic sloth Thalassocnus (T. antiquus) come from the Aguada de Lomas horizon of the Pisco Formation and were dated at roughly 7 Ma. The youngest specimen (T. carolomartini) was found in the Sacaco horizon and dated to approximately 3 Ma.^[12] Thalassocnus was preyed upon by the probable apex predators of the environment, Livyatan and megalodon.^{[13] [14]} The youngest strata belonging to the formation have been dated at 2 Ma, corresponding to the Early Pleistocene (Uquian). Fossils of the Humboldt penguin were found in these deposits at the Yauca locality.^[15]

Birds

Taxa	Species	Description	Images	class=unsortable	Notes
Spheniscus	S. humbodti	Humboldt penguin		align=center	^[16]
	S. megarhampus	Banded penguin
	S. muizoni	The oldest banded penguin		align=center	^[17] ^[18]
	S. urbinai	A larger banded penguin than S. muizoni
Ramphastosula	R. aguierrei
	R. ramirezi
Sula	S. brandi
	S. magna
	S. sulita
Morus	M. peruvianus
Perugyps	P. diazi
Ciconiidae indet.	Gen. et sp. indet.
Fulmarus	Fulmarus sp.
Pelagornis	Pelagornis sp.
Pelecanus	Pelecanus sp.
Phalacrocorax	P. aff. bougainvillii
	cf. Phalacrocorax sp.

Fish

Bony fish

Taxa	Species	Description	Images	class=unsortable	Notes
Alosinae	A. indent	A type of herring
Centropomidae	C. aff. Psamoperca	A snook fish
Triglidae	T. indent	A type of sea robin
Xiphiidae	X. ident	A sword fish
Sardinops	S. sp.	A sardine

Rays

Taxa	Species	Description	Images	class=unsortable	Notes
Myliobatis	Indeterminate	A species of eagle ray

Sharks

Taxa	Species	Description	Images	class=unsortable	Notes
Carcharias	C. taurus	The sand tiger shark
Carcharhinus	C. sp. indent	A requiem shark
Carcharodon	C. carcharias	The great white shark
	C. hubbelli
Cosmopolitodus	C. hastalis	The broad-toothed mako
Hexanchus	H. gigas	A cow shark
Isurus	I. oxyrhincus	The shortfin mako
Otodus	O. chubutensis
	O. megalodon	The largest of the megatoothed sharks (and of all fishes)

Mammals

Cetaceans

Taxa	Species	Description	Images	class=unsortable	Notes
Acrophyseter	A. deinodon	A small raptorial physeteroid
	A. robustus
Atocetus	A. iquensis	A small toothed whale
Australithax	A. intermedia	A long-snouted porpoise
Balaenoptera	B. siberi	A baleen cetacean
Belonodelphis	B. peruanus	An long delphinid
Brachydelphis	B. jahuayensis	An early delphinid
	B. mazeasi
Brujadelphis	B. ankylorostris	A river delphinid
Hemisyntrachelus	H. oligodon	An early form of orca
Incakujira	I. anillodefuego	A small baleen cetacean
	I. fordycei
Kogia	K. danomurai	A basal member of the Kogia genus. Small physeteroid
Koristocetus	K. pescei	A small sperm whale
Livyatan	L. melvillei	An 18-meter long raptorial physeteroid with 36cm (14inches) teeth
Lomacetus	L. ginsburgi	A cetacean
Mamaziphius	M. reyesi	An early beaked whale.
Miocaperea	M. pulchra	A cetothere whale
Ninoziphius	N. platyrostris	A giant beaked whale
Odobenocetops	O. leptodon	A cetacean with dual tusks
	O. peruvianus
Piscobalaena	P. nana	A small baleen whale
Piscocetus	P. sacaco	An extinct cetacean
Piscolithax	P. aenigmaticus	A porpoise
Pliopontos	P. littoralis	An early delphinid
Scaphokogia	S. cochlearis	An extinct pygmy sperm whale

Pinnipeds

Seals

Taxa	Species	Description	Images	class=unsortable	Notes
Acrophoca	A. longirostirus	A large pinniped thought to be the ancestor of the leopard seal
Australophoca	A. changorum	A phocidae seal.
Hadrokirus	H. martini	A species of true seal
Hydrarctos	H. lomasiensis	An Otariidae seal.
Magophoca	M. brevirostris	A monachinae seal.
Piscophoca	P. pacifica	A phocidae seal

Xenarthrans

Sloths

Taxa	Species	Description	Images	class=unsortable	Notes
Thalassocnus	T. antiquus	a semi-aquatic marine sloth
	T. carolomartini
	T. littoralis
	T. natans

Mollusks

Bivalves

Taxa	Species	Description	Images	class=unsortable	Notes
Dosinia	Indeterminate

Polychaetes

Taxa	Species	Description	Images	class=unsortable	Notes
Diplochaetetes	D. mexicanus

Gastropods

Taxa	Species	Description	Images	class=unsortable	Notes
Acanthina	A. obesa
	A. triangularis
Concholepas	C. kieneri
Herminespina	Indeterminate

Reptiles

Taxa	Species	Description	class=unsortable	Images	Notes
Sacacosuchus	S. cordovai	A gavialid crocodylian
Piscogavialis	P. jugaliperforatus	A gryposuchine gavialid crocodylian
Pacifichelys	P. urbinai	A sea turtle
Chelonia	Indeterminate
Eusuchia	Indeterminate

Correlations

Laventan

Laventan correlations in South America

Formation					Pisco							Map
Basin												align=center rowspan=17
Boreostemma	align=center		align=center		align=center		align=center		align=center		align=center		align=center		align=center		align=center		align=center
Hapalops	align=center		align=center		align=center		align=center		align=center		align=center		align=center		align=center		align=center		align=center
Miocochilius	align=center		align=center		align=center		align=center		align=center		align=center		align=center		align=center		align=center		align=center
Theosodon	align=center		align=center		align=center		align=center		align=center		align=center		align=center		align=center		align=center		align=center
Xenastrapotherium	align=center		align=center		align=center		align=center		align=center		align=center		align=center		align=center		align=center		align=center
	align=center		align=center		align=center		align=center		align=center		align=center		align=center		align=center		align=center		align=center
	align=center		align=center		align=center		align=center		align=center		align=center		align=center		align=center		align=center		align=center
	align=center		align=center		align=center		align=center		align=center		align=center		align=center		align=center		align=center		align=center		align=center
Rodents	align=center		align=center		align=center		align=center		align=center		align=center		align=center		align=center		align=center		align=center		align=center
Birds	align=center		align=center		align=center		align=center		align=center		align=center		align=center		align=center		align=center		align=center
Terror birds	align=center		align=center		align=center		align=center		align=center		align=center		align=center		align=center		align=center		align=center		align=center
Reptiles	align=center		align=center		align=center		align=center		align=center		align=center		align=center		align=center		align=center		align=center		align=center
	align=center		align=center		align=center		align=center		align=center		align=center		align=center		align=center		align=center		align=center		align=center
	align=center		align=center		align=center		align=center		align=center		align=center		align=center		align=center		align=center		align=center		align=center
Insects	align=center		align=center		align=center		align=center		align=center		align=center		align=center		align=center		align=center		align=center		align=center
	Fluvial			Fluvio-deltaic		Fluvio-lacustrine		Fluvio-deltaic			Fluvial
Volcanic	Yes

See also

• Bahía Inglesa Formation, contemporaneous fossiliferous formation of Chile
• Castilletes Formation, contemporaneous fossiliferous formation of the Cocinetas Basin, Colombia
• Cerro Ballena, contemporaneous fossil site of the Bahía Inglesa Formation of Chile
• Coquimbo Formation, contemporaneous fossiliferous formation of Chile
• Collón Curá Formation, contemporaneous fossiliferous formation of Patagonia, Argentina
• Honda Group, contemporaneous fossiliferous formation of Colombia
• Navidad Formation, contemporaneous fossiliferous formation of Chile
• Pebas Formation, contemporaneous fossiliferous formation of the Amazon Basin
• Urumaco, contemporaneous fossil site of the Falcón Basin, Venezuela

References

Bibliography

Further reading

• A. Alván, J. Apolín, and C. Chacaltana. 2004. Los dientes de Seláceos (Condrichthyies) y su aplicación estratigráfica en Las Lomas de Ullujaya (Ica, Perú). XIII Congreso Peruano de Geología. Resúmenes Extendidos 595–598
• A. Collareta, O. Lambert, W. Landini, C. Di Celma, E. Malinverno, R. Varas-Malca, M. Urbina and G. Bianucci. 2017. Did the giant extinct shark Carcharocles megalodon target small prey? Bite marks on marine mammal remains from the late Miocene of Peru. Palaeogeography, Palaeoclimatology, Palaeoecology 469:84-91
• R. Esperante, L. Brand, K. E. Nick, O. Poma, and M. Urbina. 2008. Exceptional occurrence of fossil baleen in shallow marine sediments of the Neogene Pisco Formation, Southern Peru. Palaeogeography, Palaeoclimatology, Palaeoecology 257:344-360
• A. Gioncada, A. Collareta, K. Gariboldi, O. Lambert, C. Di Clema, E. Bonaccorsi, M. Urbina and G. Bianucci. 2016. Inside baleen: Exceptional microstructure preservation in a late Miocene whale skeleton from Peru. Geology
• C. S. Gutstein, M. A. Cozzuol, A. O. Vargas, M. E. Suarez, C. L. Schultz and D. Rubilar-Rogers. 2009. Patterns of skull variation of Brachydelphis (Cetacea, Odontoceti) from the Neogene of the Southeastern Pacific. Journal of Mammalogy 90(2):504-519
• O. Lambert, A. Collareta, W. Landini, K. Post, B. Ramanssamy, C. Di Celma, M. Urbina and G. Bianucci. 2015. No deep diving: evidence of predation on epipelagic fish for a stem beaked whale from the Late Miocene of Peru. Proceedings of the Royal Society B 282:20151530
• J. Machare, T. DeVries, and E. Fourtanier. 1988. Oligo-Miocene transgression along the Pacific margin of South America: new paleontological and geological evidence from the Pisco basin (Peru). Géodyynamique 3(1–2):25-37
• R. Marocco and C. de Muizon. 1988. Los vertebrados del Neogeno de La Costa Sur del Perú: Ambiente sedimentario y condiciones de fosilización. Bulletin de l'Institut Français d'Études Andines 17(2):105-117
• C. de Muizon and D. P. Domning. 1985. The first records of fossil sirenians in the southeastern Pacific Ocean. Bulletin du Museum National d'Histoire Naturelle. Section C: Sciences de la Terre: Paléontologie, Géologie, Minéralogie, Paris: Muséum National d'Histoire Naturelle 7(3):189-213
• C. de Muizon. 1983. Pliopontos littoralis un nouveau Platanistidae Cetacea du Pliocene de la cote peruvienne. Comptes Rendus de l'Académie des Sciences Paris Série II (296)1101-1104
• C. de Muizon. 1978. Arctocephalus (Hydrarctos) lomasiensis, subgen. nov. et nov sp., un nouvel Otariidae du Mio-Pliocene de Sacaco. Bulletin de l'Institute Français d'Études Andines 7(3–4):169-189
• M. Urbina and M. Stucchi. 2005. Los cormoranes (Aves: Phalacrocoracidae) del Mio-Plioceno de la Formacion Pisco, Peru. Boletin de la Sociedad Geologica del Peru 99:41-49
• R. M. Varas Malca and A. Valenzuela Toro. 2011. A basal monachine seal from the middle Miocene of the Pisco Formation, Peru. Ameghiniana 48(4):R216-R217
• T. J. DeVries. 2008. Pliocene and Pleistocene Fissurella Bruguiére, 1789 (Gastropoda: Fissurellidae) from Southern Peru. The Veliger 50(2):129-148
• T. J. DeVries. 2007. Cenozoic Turritellidae (Gastropoda) from southern Peru. Journal of Paleontology 81(2):331-351
• T. J. DeVries, L. T. Groves, and M. Urbina. 2006. A new early Miocene Muracypraea Woodring, 1957 (Gastropoda: Cypraeidae) from the Pisco Basin of southern Peru. The Nautilus 120(3):101-105
• T. J. DeVries. 2003. Acanthina Fischer von Waldheim, 1807 (Gastropoda: Muricidae), an ocenebrine genus endemic to South America. The Veliger 46(4):332-350
• T. J. DeVries. 1997. Neogene Ficus (Mesogastropoda: Ficidae) from the Pisco Basin (Peru). Boletín de la Sociedad Geológica de Perú 86:11-18

Notes and References

1. Ochoa . Diana . DeVries . Thomas J. . Quispe . Kelly . Barbosa-Espitia . Angel . Salas-Gismondi . Rodolfo . Foster . David A. . Gonzales . Renzo . Revillon . Sidoine . Berrospi . Raul . Pairazamán . Luis . Cardich . Jorge . Perez . Alexander . Romero . Pedro . Urbina . Mario . Carré . Matthieu . 2022 . Age and provenance of the Mio-Pleistocene sediments from the Sacaco area, Peruvian continental margin . Journal of South American Earth Sciences . 116 . 103799 . 10.1016/j.jsames.2022.103799 . 0895-9811.
2. Brand et al., 2004
3. Brand et al., 2011
4. Lambert et al., 2010
5. De Muizon et al., 2003
6. De Muizon & Domning, 2002
7. Báez Gómez, 2006, p.65
8. Stucchi, 2007, p.368
9. Altamirano Sierra, 2013, p.3
10. Báez Gómez, 2006, p.66
11. Poma Porras et al., 2009, p.86
12. De Muizon et al., 2004, p.287
13. Parham & Pyenson, 2010, p.231
14. Bianucci et al., 2015, p.543
15. Stucchi, 2007, p.370
16. Stucchi, 2007, p.370
17. Göhlich, 2007, p.287
18. Stucchi, 2007, p.369