IEG 환경지질연구정보센터

10월 28일(목)․고생물학 | 고기후학

152 2010 추계지질과학연합학술발표회 초록집

Depositional patterns of CaCO

and opal sediments in the central equatorial Pacific Ocean:

Effect of Late Pleistocene ITCZ migration

김부근

․유찬민

․김형직

․박정기

1

부산대학교 해양시스템과학과, [email protected]

2

한국해양연구원 심해 ․ 해저자원연구부

Orbital variations in biogenic CaCO

and opal abundance of two piston cores (PC5101 and PC98N6) collected in the central equatorial Pacific Ocean were compared. Age determination of both cores was aided by graphic comparison of the CaCO

contents to the well-dated core RC11-210 from the same region. Both cores showed obvious series of CaCO

variations, which are mainly controlled by an eccentricity with an approximately 100-kyr periodicity. The orbital-scale cyclic variations in CaCO

and opal contents were apparently opposite in core PC5101 from the southern (2

N) site, with high CaCO

and low opal being present during the glacial periods. In contrast, core PC98N6 at the northern (6

N) site exhibited orbital-scale cyclic variations of CaCO

and opal contents that were almost in parallel, with high CaCO

and opal being present during the glacial periods. Different variation patterns between the two cores may be attributed to the unique response of the hydrographic condition to the glacial periods. Such a characteristic deposition of biogenic (CaCO

and opal) sediments may result from the effect of the Intertropical Convergence Zone (ITCZ). The ITCZ, located near the collection site of core PC98N6 during the interglacial periods, suppresses the diatom blooming at core PC98N6, but does not affect diatom production at core PC5101. During the glacial periods, the ITCZ migrated southward to the equator and the collection site of core PC5101 was changed to limit diatom production; however, core PC98N6 experienced more diatom blooms away from the ITCZ during the glacial periods.

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