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Punta Peligro (Paleocene of Argentina)

Also known as Chubut

Where: Chubut, Argentina (45.5° S, 67.2° W: paleocoordinates 48.1° S, 56.3° W)

• coordinate stated in text

• small collection-level geographic resolution

When: Peligran mammal zone, Hansen Member (Salamanca Formation), Danian (66.0 - 61.7 Ma)

• Banco Negro Inferior, BN1

•Peligran SALMA, considered to be middle Paleocene in age (Woodburne et al. 2014). "Marshall et al. (1981) indicated that a tuff in the upper part of the Hansen Member yielded a K-Ar date of 61▒5 m.y." (Woodburne et al. 2014). This suggests the Peligran SALMA might be early Selandian in age.

•According to Andreis et al. (1975), the upper sectionof Salamanca Formation (= Hansen Member) in the San Jorge Gulf area was accumulated under infra-littoral and transitional sea conditions. The sediments were accumulated in low energy environments yielded by submarine bars or littoral banks that had reduced the circulation in a sea with little differences between high and low tides. Based on foraminifera, Bertels (1975) assigned the upper levels of the Salamanca Formation to the Upper Danian. This hypothesis was supported by the 40K/40A isotopic age of 61 ▒ 5Ma obtained from a vitreous tuff belonging to the Hansen Member at the Caśnad┤on Hondo locality (Andreis 1977; Marshall et al. 1981). This age was subsequently corrected to 62.6 ▒ 5Ma byMarshall (1982). Additionally, two more reliable radiometric ages sampled by Marshall et al. (1981) in two basaltic units at or just under the base of the Salamanca Formation yielded ages of 64.0 ▒ 0.8Ma and 62.8 ▒ 0.8 Ma. Marshall et al. (1981, 1997) used these ages and palaeo-magnetic data to refer the overlaying BNI to polarity subchron C26r (= Danian Stage)

• group of beds-level stratigraphic resolution

Environment/lithology: mire or swamp; claystone and conglomerate

• brackish
• Package of dark sediments, comprising massive black clays with conchoidal fracture and some irregular conglomerates, with a whitish level of tuffaceous concretions on its lower part

Size classes: macrofossils, mesofossils

Preservation: original phosphate

Primary reference: R. Pascual, M. Archer, E. O. Jaureguizar, J. L. Prado, H. Godthelp and S. Hand. 1992. First discovery of monotremes in South America. Nature 356:704-706 [M. Uhen/M. Uhen] more details

Purpose of describing collection: general faunal/floral analysis

PaleoDB collection 95914: authorized by Mark Uhen, entered by Mark Uhen on 05.05.2010, edited by Philip Mannion, Jelle Zijlstra, Evangelos Vlachos and Roger Benson

Creative Commons license: CC BY (attribution)