Discovery of Late Triassic fossils in the Chonos Metamorphic Complex, Southern Chile

Citation
Jj. Fang et al., Discovery of Late Triassic fossils in the Chonos Metamorphic Complex, Southern Chile, REV GEOL CH, 25(2), 1998, pp. 165-173
Citations number
29
Categorie Soggetti
Earth Sciences
Journal title
REVISTA GEOLOGICA DE CHILE
ISSN journal
07160208 → ACNP
Volume
25
Issue
2
Year of publication
1998
Pages
165 - 173
Database
ISI
SICI code
0716-0208(199812)25:2<165:DOLTFI>2.0.ZU;2-I
Abstract
The late Triassic bivalve Monotis (Pacimonotis) aff, subcircularis Gabb ind icative of a Norian (probably early late Norian) age has been collected fro m the southeastern end of Patranca island (45 degrees 25'S-74 degrees 09'W) in the Chonos Archipelago, Southern Chile. Another fossil bivalve, Limidae gen, et sp. indet. has been collected from a small unnamed island (45 degr ees 25'S-74 degrees 10'W) 4 km to the north, and indicates a maximum Early Carboniferous, probably Mesozoic age. The fossil bearing unit is the Potran ca Formation (or Potranca Unit) which forms part of the Chonos Metamorphic Complex, interpreted as a subduction complex developed on the southwestern margin of Gondwanaland. As these rocks have been previously considered to b e of Paleozoic age (Late Silurian-Early Devonian), the geologic history of this part of the continental margin must be reinterpreted. These fossils pr ovide clear evidence that marine depositional processes persisted within th e Chonos Metamorphic Complex during Late Triassic time.