A preliminary study on oxygen isotope of ice cores of Collins Ice Cap,King George Island,Antarctica

Glacier forming material shows no difference of oxygen isotope for different heights above sea level on Big Dome of Collins Ice Cap. δ 18 O variations of surface firn with depth(time) are extremely similar. Owing to the material and energy exchange between different annual layers, homogeneity of oxygen isotope arises and leads to no avail of δ 18 O ice core dating on Big Dome Summit of Collins Ice Cap. Affected by seasonal variations of temperature, oxygen isotope composition of winter layer is distinctly different from that of summer layer whose δ 18 O value is higher and variation coefficient is smaller. By means of direct comparison oxygen isotope/temperature gradient of Collins Ice Cap is defined as 0.74‰/℃ in use of annual mean temperature and δ 18 O value on Big Dome Summit and Small Dome Top of Collins Ice Cap.