Applying distribution characteristics of chemical elements during soil-forming process to resume palaeo-environmental evolution is a key field in the research of past global changes. This paper divided the continuous strata of the Zhongba site in Chongqing into 12 sub-layers according to cultural sequence over last 5 ka, measuring Rb, Sr, Cr and Cu contents respectively by XRF and ICP-AES methods. Results indicated that Cr has similar chemical nature as Rb with low activity and is apt to deposit in fine sand materials. Meanwhile, Cu and Sr are easy to be transported over the weathering process and enrich in claypan. A linear regression demonstrated that Cr/Cu ratios are positively relative to Rb/Sr ratios. After comparing variation curves of Cr/Cu ratios with climatic records of peat humification in Hongyuan, northeast region of the Tibet Plateau in last 5 ka, they both are well consistent with each other. Therefore, this paper suggested that Cr/Cu ratios as Rb/Sr be a reliable proxy to indicate palaeo-environment even with higher accuratcy. Obviously, Cr/Cu ratios will be significant in geo-archaeological research.
LI Zhong-xuan, ZHU Cheng, ZHU Qing, MA Chun-mei, ZHANG Guang-sheng, OUYANG Jie
. Variation of Cr/Cu Ratios in Zhongba Profile and Its Indication on Palaeo-environment over Last 5 ka[J]. SCIENTIA GEOGRAPHICA SINICA, 2008
, 28(6)
: 799
-803
.
DOI: 10.13249/j.cnki.sgs.2008.06.799
[1] 陈 骏, 仇 纲, 季俊峰, 等. 最近130 ka黄土高原夏季风变迁的Rb和Sr地球化学证据[J]. 科学通报, 1996, 41(21): 1963~1966.
[2] Chen J, An Z S, John H. Variation of Rb/Sr ratios in the loess- paleosol sequences of central China during the last 130 000 years and their implications for monsoon paleoclimatology[J]. Quaternary Research, 1999, 51: 215-219.
[3] 黄 润, 朱 诚, 王升堂. 天堂寨泥炭地层的磁化率、Rb/Sr值及其反映的古气候意义[J]. 地理科学, 2007, 27(3): 385~391.
[4] 胡金明, 崔海亭, 李宜垠. 西辽河流域全新世以来人地系统演变历史的重建[J]. 地理科学, 2002, 22(5): 535~539.
[5] 贾耀峰, 黄春长, 庞奖励,等. 全新世黄土剖面Li/Ba值变化及古气候意义[J]. 第四纪研究, 2005, 25(6): 770~776.
[6] 庞奖励, 黄春长, 刘安娜, 等. 黄土高原南部全新世黄土-古土壤序列若干元素分布特征及意义[J]. 第四纪研究, 2007, 27(3): 357~364.
[7] 张 强, 杨达源, 施雅风, 等.川江中坝遗址5 000年来洪水事件研究[J]. 地理科学, 2004, 24(6): 715~710.
[8] Glodstein S L. Decoupled evolution of Nd and Sr isotopes in the continental crust and the mantle[J]. Nature, 1988, 336: 733-738.
[9] Ingram B L, Sloan D. Strontium isotopic composition of estuarine sediments as paleosalinity-paleoclimate indicator[J]. Science, 1992, 255: 68-72.
[10] Dasch E J. Strontium isotopes in weathering profiles, deep-sea sediments, and sedimentary rocks[J]. Geochimca et Cosmochimca Acta, 1969, 33: 1521-1552.
[11] 牟保磊. 元素地球化学[M]. 北京:北京大学出版社, 1999: 34~60.
[12] Lee Y J, Elzinga E J, Reeder R J. Cu(II) adsorption at the calcite–water interface in the presence of natural organic matter: Kinetic studies and molecular-scale characterization[J]. Geochimica et Cosmochimica Acta,2005, 69 (1): 41-69.
[13] 熊尚发, 刘东生, 丁仲礼. 两个冰期-间冰期旋回的黄土记录及其古气候意义[J]. 地理科学, 2002, 22(1): 18~24.
[14] 洪业汤, 姜洪波, 陶发祥,等. 近5 ka温度的金川泥炭δ18O记录[J]. 中国科学(D辑), 1997, 27(6): 525~530.
[15] 杨永兴, 王世岩. 8.0 ka B.P.以来三江平原北部沼泽发育和古环境演变研究[J]. 地理科学, 2003, 23(1):32~38.
[16] 王心源,吴 立,张广胜,等安徽巢湖全新世湖泊沉积物磁化率与粒度组合的变化特征及其环境意义[J]. 地理科学,2008,28(4):548~553.
[17] Charman D J, Caseldine C, BarkerA,et al. Paleohydrological records from peat profiles and speleothems in Sutherland, Northwest Scotland[J]. Quaternary Research, 2001, 55: 223-234.
[18] 王 华, 洪业汤, 朱咏煊, 等. 红原泥炭腐殖化度记录的全新世气候变化[J]. 地质地球化学, 2003, 31(2): 51~56.
[19] 马春梅, 朱 诚, 郑朝贵, 等. 晚冰期以来神农架大九湖泥炭高分辨率气候变化的地球化学记录[J]. 科学通报, 2008, 53(增刊1): 26~37.