Middle Jurassic (Late Callovian) dinoflagellate cysts from the Lotena Formation of the Neuquén Basin, Argentina and their palaeogeographical significance

RIDING, JAMES B.; QUATTROCCHIO, MIRTA E.; MARTÍNEZ, MARCELO A.

REVIEW OF PALAEOBOTANY AND PALYNOLOGY

ELSEVIER SCIENCE BV

Año: 2010

0034-6667

The Lotena Formation from two localities, Puente del Arroyo Picún Leufú and Portada Covunco, in the Neuquén Basin in west-central Argentina produced dinoflagellate cyst assemblages of low-moderate diversity. These are indicative of a Late Callovian age by comparison with northwest Europe. This is consistent with the ammonite faunas at both localities. The dinoflagellate cyst floras are reminiscent of northwest Europe and surrounding areas. Marine palynomorphs typical of Australasia and the Arctic are absent. The similarity with Europe means that there was an open marine connection between western Tethys and the Neuquén Basin during the Late Callovian. This is interpreted as being the Hispanic Corridor, with the palynofloras transported in a southwesterly direction on the circum-Tropical Marine Current. This trans-Pangean equatorial seaway first began to allow biotal interchange during the Middle Jurassic and this study proves that the open marine connection had been established by the Late Callovian. The biotic similarities between Europe and the Neuquén Basin based on dinoflagellate cysts is entirelt consistent with other evidence from, for example, facies belts.