New U-Pb zircon ages of the Sandbian (Upper Ordovician) "Big K-bentonite" in Baltoscandia (Estonia and Sweden) by LA-ICPMS

作者：Bauert Heikki^*; Isozaki Yukio; Holmer Lars Erik; Aoki Kazumasa; Sakata Shuhei; Hirata Takafumi

来源：GFF, 2014, 136(1): 30-33.

DOI：10.1080/11035897.2013.862854

• K-bentonite
• Kinnekulle
• U-Pb age
• zircon
• laser ablation-inductively coupled plasma mass spectrometer
• Baltoscandia

Oscillatory-zoned euhedral single zircons from the upper Sandbian (Upper Ordovician) Kinnekulle K-bentonite exposed in a hillock at Paaskula in Estonia and at the type locality on Mt Kinnekulle in Sweden were dated in a grain-by-grain manner by laser ablation-inductively coupled plasma mass spectrometer. The U-Pb (weighed mean) ages of the 25 grains from Mt Kinnekulle and 24 grains from Paaskula are 453.4 +/- 6.6 and 454.9 +/- 4.9Ma, respectively. This study provides the first ca. 454Ma (late Sandbian) age for the Ordovician K-bentonite in northern Estonia and confirmed its correlation with the type Kinnekulle bed across the Baltic Sea.

• 出版日期2014-1-2