Abstract: Paleomagnetic and rock magnetic studies are undertaken in sediment core D1-7 of Bransfield Strait, Antarctic, to obtain continuous variation of relative paleointensity (RPI) and direction of geomagnetic field. The lithologies of the core are mainly gray soft and plastic clay, a dark tephra layer at the lower part 2.20-2.21 m with sharp lower contact and gradual upper contact. Combined with AMS¹⁴C dating of bulk sediment and foram (Wang R J et al unpublished data), RPI and direction of geomagnetic field provide a continuous time scale of the last 12 ka, among which RPI comparing with Laguna Potrok Aike lake of South America produced six tie points, meanwhile, inclination and declination comparing with this record results in additional six tie points. Drastic changes of bottom current (1000 m, Antarctic deep water) for early, middle and late Holocene are revealed by anisotropy of magnetic susceptibility (AMS), as well as magnetic concentration, grain size and wet density. These changes basically are controlled by summer insolation at 65 ?S, therefore by the summer monsoon precipitation in cycles of precession. Millennial scale variations are also observed but no other records with similar resolution are available to decipher origin and ranges of these climate or environment events. The ages from secular variation are systematically younger/older after/before 6 ka B. P.. The mixing of different water masses and intermediate, deep water evolution related with Antarctic ice sheet retreat during Holocene are reasonable reasons for complex carbon input in Bransfield Strait. The intensity and direction of geomagnetic field recorded by sediments can avoid this influence and provide reliable age information. An average sedimentation rate of 25 cm/ka for the whole Holocene in D1-7 suggest a rich and constant terrigenous input in Bransfield Strait, Antarctic.

Key words: Bransfield Strait, Antarctic, relative paleointensity of geomagnetic field, inclination, secular variation of geomagnetic field