Floating tephra was deposited together with ice core, snow layer, abyssal sediment, lake sediments, and other geological records. It is of great significance to interpret the impact on the climate change of volcanic eruptions from these geological records. It is the first time that volcanic glass was discovered from the peat of Jinchuan （金川） Maar, Jilin （吉林） Province, China. And it is in situ sediments from a near-source explosive eruption according to particle size analysis and identification results. The tephra were neither from Tianchi （天池） volcano eruptions, Changbai （长白） Mountain, nor from Jinlongdingzi （金龙顶子） volcano about 1 600 aBP eruption, but maybe from an unknown eruption of Longgang （龙岗） volcano group according to their geochemistry and distribution. Geochemical characters of the tephra are similar to those of Jinglongdingzi, which are poor in silica, deficient in alkali, Na2O content is more than K2O content, and are similar to distribution patterns of REE and incompatible elements, which helps to speculate that they originated from the same mantle magma with rare condemnation, and from basaltic explosive eruption of Longgang volcano group. The tephra, from peat with age proved that the eruption possibly happened in 15 BC-26 AD, is one of Longgang volcano group eruption that was not recorded and is earlier than that of Jinglongdingzi about 1 600 aBP eruption. And the sedimentary time of tephra is during the period of low temperature alteration, which may be the influence of eruption toward the local climate according to the correlativity of eruption to local temperature curve of peat cellulose oxygen isotope.
The article emphatically reviews the research progress in interconnections between the East Asian and Indian Ocean summer monsoons, between the Asian monsoon and the El Ni?o-South- ern Oscillation (ENSO) activity, and between the monsoon, ENSO and the changing of the North At- lantic climate during the Holocene. According to the studies of recent years, it is found that the intensity variations of the East Asian and Indian Ocean sum- mer monsoons show an opposite relationship, which may be closely related to the phenomena of ENSO in the equatorial Pacific Ocean and the variation of the deep-water formation of the North Atlantic Ocean on the interannual to orbital time scales. The 4k and 8k events occurring at around 4200 and 8200 a BP, re- spectively, might be the two in a series of severe pa- leo-El Ni?o events during the Holocene, strongly re- flecting the interactions and influences of the mon- soons, ENSO and the North Atlantic climate. In order to better understand the relationships between these paleoclimatic phenomena, scientists need to strengthen the research work on the Asian monsoon division and the comparison between monsoon proxy records, and the study on the proxy record of sea surface temperature with high time-resolution in the equatorial Pacific Ocean and the simulation research of paleoclimate condition.
