黄河古河道的分布及其年代学框架的建立对于探讨黄河迁移规律、重建古气候演化历史具有重要意义。通过Landsat8遥感影像解译、1∶5万野外地质地貌调查、钻孔资料分析,结合剖面实测基本判定了色尔腾山以南至现代黄河以北河套平原区黄河...黄河古河道的分布及其年代学框架的建立对于探讨黄河迁移规律、重建古气候演化历史具有重要意义。通过Landsat8遥感影像解译、1∶5万野外地质地貌调查、钻孔资料分析,结合剖面实测基本判定了色尔腾山以南至现代黄河以北河套平原区黄河埋藏古河道的分布,,采用OSL与14C测年较精确地确定了黄河古河道的年代。依据年代学研究结果,将全新世黄河古河道划分为三期:Ⅰ期古河道,分南北两支,南支分布在复兴镇西北部,埋深2~6 m,北支分布于呼勒斯太中南部,埋深8.2~9 m,时代为9.93~7.4 ka B.P.;Ⅱ期古河道,河道主体分布在色尔腾山山前,呈北西─南东向,埋藏于现今乌加河古河道下部4~11m处,南北最宽处约1.5km。塔尔湖区存在同一期的古河道,埋深7~9 m,以东西向展布为主,时代为7.4~4.1 ka B.P.;Ⅲ期古河道,呼勒斯太中部、塔尔湖中南部及复兴南部都曾发育,但河道主体为塔尔湖区的古河道,埋深2~9 m,时代为4.1~1.2 ka B.P.。黄河古河道分布及时代确定有助于更深入地研究黄河在河套段演化历史,为河套地区的水利建设和农业生产提供参考和借鉴。展开更多
Transported by wind and water,the relatively old sediments can deposit in the terminal lake of an inland drainage basin.The reworking effect can affect the lake sediments 14 C dating and explanations for proxies.The Z...Transported by wind and water,the relatively old sediments can deposit in the terminal lake of an inland drainage basin.The reworking effect can affect the lake sediments 14 C dating and explanations for proxies.The Zhuye Lake is the terminal lake of the Shiyang River Basin.Previous studies indicated that sediments in different locations of the lake basin showed different climatic change patterns.And then,some radiocarbon dates were inverted for some Late Pleistocene sections.Whether this phenomenon is related with the reworking effect? The pollen concentrates 14 C dating can avoid the reservoir effect,which is an ideal method for studying the reworking effect.In this study,we used the pollen concentrates as dating materials and dated five Holocene sections in the Zhuye Lake Basin.Based on the 14 C dates comparison between the pollen concentrates,organic matter,and shells,the pollen concentrates dates are relatively older than other dating materials.Based on the result,the reworking effect worked in the Zhuye Lake Basin during the Holocene;however,in different locations of the lake basin the reworking effects were in different levels.Furthermore,the Holocene lacustrine deposits were formed mostly during the early and middle Holocene.This study provided clues for reworking effect studies of other lakes in arid China.展开更多
文摘黄河古河道的分布及其年代学框架的建立对于探讨黄河迁移规律、重建古气候演化历史具有重要意义。通过Landsat8遥感影像解译、1∶5万野外地质地貌调查、钻孔资料分析,结合剖面实测基本判定了色尔腾山以南至现代黄河以北河套平原区黄河埋藏古河道的分布,,采用OSL与14C测年较精确地确定了黄河古河道的年代。依据年代学研究结果,将全新世黄河古河道划分为三期:Ⅰ期古河道,分南北两支,南支分布在复兴镇西北部,埋深2~6 m,北支分布于呼勒斯太中南部,埋深8.2~9 m,时代为9.93~7.4 ka B.P.;Ⅱ期古河道,河道主体分布在色尔腾山山前,呈北西─南东向,埋藏于现今乌加河古河道下部4~11m处,南北最宽处约1.5km。塔尔湖区存在同一期的古河道,埋深7~9 m,以东西向展布为主,时代为7.4~4.1 ka B.P.;Ⅲ期古河道,呼勒斯太中部、塔尔湖中南部及复兴南部都曾发育,但河道主体为塔尔湖区的古河道,埋深2~9 m,时代为4.1~1.2 ka B.P.。黄河古河道分布及时代确定有助于更深入地研究黄河在河套段演化历史,为河套地区的水利建设和农业生产提供参考和借鉴。
基金supported by the National Natural Science Foundation of China (Grant Nos. 41001116 and J1030519)the Fundamental Research Fund for the Central Universities (Grant No. LZUJBKY-2010-99)
文摘Transported by wind and water,the relatively old sediments can deposit in the terminal lake of an inland drainage basin.The reworking effect can affect the lake sediments 14 C dating and explanations for proxies.The Zhuye Lake is the terminal lake of the Shiyang River Basin.Previous studies indicated that sediments in different locations of the lake basin showed different climatic change patterns.And then,some radiocarbon dates were inverted for some Late Pleistocene sections.Whether this phenomenon is related with the reworking effect? The pollen concentrates 14 C dating can avoid the reservoir effect,which is an ideal method for studying the reworking effect.In this study,we used the pollen concentrates as dating materials and dated five Holocene sections in the Zhuye Lake Basin.Based on the 14 C dates comparison between the pollen concentrates,organic matter,and shells,the pollen concentrates dates are relatively older than other dating materials.Based on the result,the reworking effect worked in the Zhuye Lake Basin during the Holocene;however,in different locations of the lake basin the reworking effects were in different levels.Furthermore,the Holocene lacustrine deposits were formed mostly during the early and middle Holocene.This study provided clues for reworking effect studies of other lakes in arid China.
