Dimorphinites (Ammonoidea, Jurassic, Upper Bajocian) in the Precordillera of Northern Chile



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Fernández López, Sixto Rafael and Chong Díaz, Guillermo B. (2011) Dimorphinites (Ammonoidea, Jurassic, Upper Bajocian) in the Precordillera of Northern Chile. Journal of paleontology, 85 (3). pp. 395-405. ISSN 0022-3360

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Official URL: http://www.psjournals.org/loi/pleo


A new upper Bajocian ammonite assemblage containing the morphoceratids Dimorphinites dimorphus
(d’Orbigny) and Vigoriceras defrancei (d’Orbigny) is reported from the circum-Pacific area. These ammonites were
found at the top of the Torcazas Formation, in the Quebrada San Pedro area, Precordillera of northern Chile.
Taphonomic, systematic, and paleobiogeographic data confirm these dimorphs were part of indigenous populations
within the Tarapaca Basin, belonging to the same demic biospecies: Dimorphinites defrancei (d’Orbigny). The West
Tethyan and East-Pacific distribution of D. defrancei corroborates the availability of the migratory seaway, the socalled
Hispanic Corridor, between the western Tethys and the eastern Pacific Ocean during the upper Bajocian
Parkinsoni Zone. The discovery of this upper Bajocian Dimorphinites assemblage provides a new biochronostratigraphic
horizon in the Tarapaca Basin and an interoceanic correlation point for the latest Bajocian.

Item Type:Article
Uncontrolled Keywords:Ammonoidea, Jurassic, Upper Bajocian, Northern Chile
Subjects:Sciences > Geology > Paleontology
ID Code:24098
Deposited On:07 Jan 2014 13:16
Last Modified:11 Dec 2018 08:42

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