Paleointensity studies of a lava succession from Jilin Province, northeastern China: Evidence for the Blake event

Paleomagnetic results are presented from a volcanic sequence in Tianchi, Ji lin Province, northeastern China. Five basalt lava flows can be identified at the sampling site with ages from 210+/-4 to 88+/-15 kyr B.P. Rock magnet ic analyses and reflected light microscopy indicate that magnetite with a s ignificant fraction of pseudo-single-domain grains is dominant in these lav a flows. A single stable characteristic remanence can be thermally isolated above 150-200 degrees C. Intermediate direction is preserved in lava 3 at an age of similar to 123 kyr corresponding to the Blake event, and its virt ual geomagnetic pole is located in eastern Asia and Australia. From a total of 121 specimens used for paleointensity determinations by the Thellier me thod in an argon atmosphere, 34 specimens yielded reliable results with low within-flow scatter. The results indicate that a significant intensity low is coincident with the Blake event.