SHRIMP zircon U-Pb dating for Chibaisong No.1 gabbro in the Tonghua area, Jilin Province, is discussed in the paper.
This paper presents the first SHRIMP zircon age data from bentonitic ash fall layers intercalated with the Irati sedimentary rocks, as well as palynofossils retrieved from the PETROBRAS-Six mine, Paraná State, southern Brazil.
SHRIMP analysis performed on the euhedral and prismatic grains revealed an age of ca.
278.4 ± 2.2 Ma (7 points with 95% confidence) interpreted as the crystallization age of the volcanic eruption.
The Permian Irati Formation is one the most important oil source horizons within the Paraná Basin, and consists mainly of siltstones, gray claystones, as well as organic-rich claystones intercalated with limestones.
Zircon morphology based on cathodoluminescence images includes two different populations: a dominant population of euhedral, prismatic, elongate to acicular grains which are most likely related to an ash fall volcanism; and a population of rounded to large prismatic grains, that were interpreted as detrital grains.