Geochemical study of boron isotopes in the process of loess weathering  

作　　者：赵志琦 刘丛强 肖应凯 郎赟超 

机构地区：[1]State Key Laboratory of Environmental Geochemistry,Institute of Geochemistry,Chinese Academy of Sciences [2]Qinghai Institute of Salt Lakes,Chinese Academy of Sciences

出　　处：《Science China Earth Sciences》2003年第2期106-116,共11页中国科学（地球科学英文版）

基　　金：the State Outstanding Young Scientists Foundation(Grant No.94625304)and the"Climbing Program"sponsored by the Ministry of Science and Technology(Grant No.95-yu-39)

摘　　要：In this paper the boron contents and boron isotopic composition ofacid-soluble phases in loess and paleosol samples are determined for the first time. The boroncontents of acid-soluble phases in the Luochuan loess section (S_0—S_2) vary within the range of(0.8—2.7)x10^(-6) and their δ^(11)B values vary from -1.8 per thousand to +18.6 per thousand,mostly within the range of 0—+10 per thousand. The boron contents and δ^(11)B values of paleosollayers are higher than those of loess layers, especially in the loess layer S_1. Varying chemicalweathering intensity and loess adsorption capability are the main factors leading to the variationsof boron contents and δ^(11)B values of acid-soluble phases in the loess section. The variation ofchemical weathering intensity in response to the variation of climatic conditions seems to be themain factor leading to the variations of boron contents and δ^(11)B values of acid-soluble phasesin the loess section.In this paper the boron contents and boron isotopic composition of acid-soluble phases in loess and paleosol samples are determined for the first time. The boron contents of acid-soluble phases in the Luochuan loess section (S0 S2) vary within the range of (0.8—2.7)?0-6 and their d 11B values vary from 1.8?to +18.6? mostly within the range of 0—+10? The boron contents and d 11B values of paleosol layers are higher than those of loess layers, especially in the loess layer S1. Varying chemical weathering intensity and loess adsorption capability are the main fac-tors leading to the variations of boron contents and d 11B values of acid-soluble phases in the loess section. The variation of chemical weathering intensity in response to the variation of climatic con-ditions seems to be the main factor leading to the variations of boron contents andδ11B values of acid-soluble phases in the loess section.

关 键 词：LOESS-PALEOSOL boron isotopic composition chemical weathering adsorption paleo-climate 

分 类 号：P597[天文地球—地球化学]