青海湖滩坝分布规律及其古气候意义
|
摘要
青海湖是我国最大的内陆湖盆,对气候变化十分敏感,而滩坝是青海湖滨浅湖带最为发育的沉积类型之一,其滩坝分布规律对晚更新世以来的古气候演化具有重要指示意义。在对青海湖一郎剑剖面进行实地考察的基础之上,对滩坝的分布规律及沉积特征进行精细解剖。通过分析总结前人相关测年数据,并与青海湖滩坝分布规律进行对比,发现青海湖湖平面升降对滩坝分布有明显的控制作用,建立了18 ka以来青海湖滩坝的演化过程,并将近18 ka以来青海湖湖平面升降史分为4个阶段:(1)更新世末温湿期,湖平面在海拔3 197～3 202 m附近波动;(2)全新世冷干期,湖平面近乎干涸;(3)全新世大暖期,湖平面处于全新世以来的最高值,约为3 212 m;(4)全新世凉湿期,湖平面回落到3 200 m附近,并在近2. 5 ka湖平面加速下降。在晚更新世和晚全新世时,湖平面在海拔3 202 m附近波动时间较长,在该海拔范围内,形成了规模较大的复合滩坝;在早全新世,青海湖平面最低,多发育风成黄土和潟湖沉积;在中全新世,湖平面最高,形成了距离现今湖平面最远的数列单体滩坝。
The Qinghai Lake is the largest inland lake in China,and is sensitive to climate change. As an important type of shallow lake sediments,the distribution of beach bars reflects the paleoclimatic evolution of the Qinghai Lake. The southern part of the Qinghai Lake develops a large number of beach bars,which represents an ideal place for studying the beach bar distribution in the lake. Based on field cross-section( trenches and deep pits) investigation around Yilangjian,the beach bar distribution and sedimentary characteristics there were described in detail,and are compared with the reconstructed lake level change curve. It is found that the reconstructed lake-level change curve of the Qinghai Lake has significant control over the beach bar distribution,and the evolution of Qinghai Lake beach bar with the lake-level rise and fall since 18 ka is reconstructed,which comprises four stages:( 1) During the warm and humid end Pleistocene,the lake level fluctuated between3,197-3,202 m;( 2) In the cold and dry period of the Holocene,the Qinghai Lake was almost dry;( 3) Inthe warmest period of the Holocene,the lake-level was at its highest since the beginning of the Holocene;( 4)During the cool and humid period of the Holocene,the lake level fell back to 3,200 m and accelerated down in the 2. 5 ka. During the Late Pleistocene and Late Holocene,the lake level fluctuated for a long time around the altitude of 3,202 m. In this altitude range,a large-scale compound beach bar was formed. In the Early Holocene,the Qinghai Lake was at its lowest level and more loess and lagoon were developed. In the Middle Holocene,the lake level was at its highest,forming a series of monolithic beach bars furthest from the current lake level.
The Qinghai Lake is the largest inland lake in China,and is sensitive to climate change. As an important type of shallow lake sediments,the distribution of beach bars reflects the paleoclimatic evolution of the Qinghai Lake. The southern part of the Qinghai Lake develops a large number of beach bars,which represents an ideal place for studying the beach bar distribution in the lake. Based on field cross-section( trenches and deep pits) investigation around Yilangjian,the beach bar distribution and sedimentary characteristics there were described in detail,and are compared with the reconstructed lake level change curve. It is found that the reconstructed lake-level change curve of the Qinghai Lake has significant control over the beach bar distribution,and the evolution of Qinghai Lake beach bar with the lake-level rise and fall since 18 ka is reconstructed,which comprises four stages:( 1) During the warm and humid end Pleistocene,the lake level fluctuated between3,197-3,202 m;( 2) In the cold and dry period of the Holocene,the Qinghai Lake was almost dry;( 3) Inthe warmest period of the Holocene,the lake-level was at its highest since the beginning of the Holocene;( 4)During the cool and humid period of the Holocene,the lake level fell back to 3,200 m and accelerated down in the 2. 5 ka. During the Late Pleistocene and Late Holocene,the lake level fluctuated for a long time around the altitude of 3,202 m. In this altitude range,a large-scale compound beach bar was formed. In the Early Holocene,the Qinghai Lake was at its lowest level and more loess and lagoon were developed. In the Middle Holocene,the lake level was at its highest,forming a series of monolithic beach bars furthest from the current lake level.
引文
[1]沈吉.末次盛冰期以来中国湖泊时空演变及驱动机制研究综述:来自湖泊沉积的证据[J].科学通报,2012,57(34):3228-3242.
[2]闫立娟,郑绵平,魏乐军.近40年来青藏高原湖泊变迁及其对气候变化的响应[J].地学前缘,2016,23(4):310-323.
[3]韩建恩,朱大岗,邵兆刚,等.黄河源地区优云湖相地层环境代用指标反映的古环境变化[J].现代地质,2013,27(2):269-277.
[4]李国斌,姜在兴,陈诗望,等.利津洼陷沙四上亚段滩坝沉积特征及控制因素分析[J].中国地质,2008,35(5):911-921.
[5]边千韬,刘嘉麒,罗小全,等.青海湖的地质构造背景及形成演化[J].地震地质,2000,22(1):20-26.
[6]宋春晖,王新民,师永民,等.青海湖现代滨岸沉积微相及其特征[J].沉积学报,1999,17(1):51-57.
[7]于炳松,董海良,蒋宏忱,等.青海湖底沉积物中球状白云石集合体的发现及其地质意义[J].现代地质,2007,21(1):66-70.
[8]金振奎,苏奎,张永生,等.湿地的沉积特征及石油地质意义[J].中国石油大学学报(自然科学版),2011,35(3):1
[9]姜正龙,邓宏文,林会喜,等.古地貌恢复方法及应用——以济阳坳陷桩西地区沙二段为例[J].现代地质,2009,23(5):865-871.
[10]董艳蕾,朱筱敏,赵东娜.准噶尔盆地车排子地区下白垩统沉积体系分布及油气成藏模式[J].现代地质,2015,29(1):71-79.
[11]曾智伟,杨香华,舒誉,等.恩平凹陷古近系文昌组构造古地貌特征及砂体展布规律——少井条件下储集砂体预测与评价[J].现代地质,2015,29(4):804-815.
[12]张彭熹,张保珍,杨文博.青海湖冰后期水体环境的演化[J].沉积学报,1988,6(2):1-14.
[13] MADSEN D B,HAIZHOU M,RHODE D,et al. Age constraints on the late Quaternary evolution of Qinghai Lake,Tibetan Plateau[J]. Quaternary Research,2008,69(2):316-325.
[14] LIU X,LAI Z,MASEN D,et al. Lake level variations of Qinghai Lake in northeastern Qinghai-Tibetan Plateau since 3. 7 ka based on OSL dating[J]. Quaternary International,2011,236(1/2):57-64.
[15] LISTER G S,KELTS K,ZAO C K,et al. Lake Qinghai,China:closed-basin like levels and the oxygen isotope record for ostracoda since the latest Pleistocene[J]. Palaeogeography,Palaeoclimatology,Palaeoecology,1991,84(1):141-162.
[16] LIU X,LAI Z,MADSEN D,et al. Last deglacial and Holocene lake level variations of Qinghai Lake,north-eastern Qinghai-Tibetan Plateau[J]. Journal of Quaternary Science,2015,30(3):245-257.
[17] RHODE D,HAIZHOU M,MADSEN D B,et al. Paleoenvironmental and archaeological investigations at Qinghai Lake,western China:Geomorphic and chronometric evidence of lake level history[J]. Quaternary International,2010,218(1/2):29-44.
[18] LIU X,LAI Z,FAN Q,et al. Timing for high lake levels of Qinghai Lake in the Qinghai-Tibetan Plateau since the Last Interglaciation based on quartz OSL dating[J]. Quaternary Geochronology,2010,5(2/3):218-222.
[19] LIU W,LI X,AN Z,et al. Total organic carbon isotopes:A novel proxy of lake level from Lake Qinghai in the Qinghai-Tibet Plateau,China[J]. Chemical Geology, 2013, 347:153-160.
[20]袁宝印,陈克造,BOWLER J M,等.青海湖的形成与演化趋势[J].第四纪研究,1990,10(3):233-243.
[21]张彭熹,张保珍,钱桂敏,等.青海湖全新世以来古环境参数的研究[J].第四纪研究,1994,14(3):225-238.
[22]陈克造,BOWLER J M,KELTS K.四万年来青藏高原的气候变迁[J].第四纪研究,1990,10(1):21-31.
[23]余俊清,KELTS K.末次冰消期晚期青藏高原东北部气候变化[J].第四纪研究,2002,22(5):413-423.
[24] AN Z,COLMAN S M,ZHOU W,et al. Interplay between the Westerlies and Asian monsoon recorded in Lake Qinghai sediments since 32 ka[J]. Scientific Reports,2012,2(8):619.
[25]王苏民,施雅风.晚第四纪青海湖演化研究析视与讨论[J].湖泊科学,1992,4(3):1-9.
[26]曾承.青海湖碳酸盐氧同位素环境记录再认识[J].盐湖研究,2007,15(1):16-19.
[27]赵存法,鹿化煜,周亚利,等.青海湖地区冰消期以来气候变化的黄土记录[J].高校地质学报,2009,15(1):135-140.
[28]刘兴起,王苏民,沈吉.青海湖QH-2000钻孔沉积物粒度组成的古气候古环境意义[J].湖泊科学,2003,12(2):112-117.
[2]闫立娟,郑绵平,魏乐军.近40年来青藏高原湖泊变迁及其对气候变化的响应[J].地学前缘,2016,23(4):310-323.
[3]韩建恩,朱大岗,邵兆刚,等.黄河源地区优云湖相地层环境代用指标反映的古环境变化[J].现代地质,2013,27(2):269-277.
[4]李国斌,姜在兴,陈诗望,等.利津洼陷沙四上亚段滩坝沉积特征及控制因素分析[J].中国地质,2008,35(5):911-921.
[5]边千韬,刘嘉麒,罗小全,等.青海湖的地质构造背景及形成演化[J].地震地质,2000,22(1):20-26.
[6]宋春晖,王新民,师永民,等.青海湖现代滨岸沉积微相及其特征[J].沉积学报,1999,17(1):51-57.
[7]于炳松,董海良,蒋宏忱,等.青海湖底沉积物中球状白云石集合体的发现及其地质意义[J].现代地质,2007,21(1):66-70.
[8]金振奎,苏奎,张永生,等.湿地的沉积特征及石油地质意义[J].中国石油大学学报(自然科学版),2011,35(3):1
[9]姜正龙,邓宏文,林会喜,等.古地貌恢复方法及应用——以济阳坳陷桩西地区沙二段为例[J].现代地质,2009,23(5):865-871.
[10]董艳蕾,朱筱敏,赵东娜.准噶尔盆地车排子地区下白垩统沉积体系分布及油气成藏模式[J].现代地质,2015,29(1):71-79.
[11]曾智伟,杨香华,舒誉,等.恩平凹陷古近系文昌组构造古地貌特征及砂体展布规律——少井条件下储集砂体预测与评价[J].现代地质,2015,29(4):804-815.
[12]张彭熹,张保珍,杨文博.青海湖冰后期水体环境的演化[J].沉积学报,1988,6(2):1-14.
[13] MADSEN D B,HAIZHOU M,RHODE D,et al. Age constraints on the late Quaternary evolution of Qinghai Lake,Tibetan Plateau[J]. Quaternary Research,2008,69(2):316-325.
[14] LIU X,LAI Z,MASEN D,et al. Lake level variations of Qinghai Lake in northeastern Qinghai-Tibetan Plateau since 3. 7 ka based on OSL dating[J]. Quaternary International,2011,236(1/2):57-64.
[15] LISTER G S,KELTS K,ZAO C K,et al. Lake Qinghai,China:closed-basin like levels and the oxygen isotope record for ostracoda since the latest Pleistocene[J]. Palaeogeography,Palaeoclimatology,Palaeoecology,1991,84(1):141-162.
[16] LIU X,LAI Z,MADSEN D,et al. Last deglacial and Holocene lake level variations of Qinghai Lake,north-eastern Qinghai-Tibetan Plateau[J]. Journal of Quaternary Science,2015,30(3):245-257.
[17] RHODE D,HAIZHOU M,MADSEN D B,et al. Paleoenvironmental and archaeological investigations at Qinghai Lake,western China:Geomorphic and chronometric evidence of lake level history[J]. Quaternary International,2010,218(1/2):29-44.
[18] LIU X,LAI Z,FAN Q,et al. Timing for high lake levels of Qinghai Lake in the Qinghai-Tibetan Plateau since the Last Interglaciation based on quartz OSL dating[J]. Quaternary Geochronology,2010,5(2/3):218-222.
[19] LIU W,LI X,AN Z,et al. Total organic carbon isotopes:A novel proxy of lake level from Lake Qinghai in the Qinghai-Tibet Plateau,China[J]. Chemical Geology, 2013, 347:153-160.
[20]袁宝印,陈克造,BOWLER J M,等.青海湖的形成与演化趋势[J].第四纪研究,1990,10(3):233-243.
[21]张彭熹,张保珍,钱桂敏,等.青海湖全新世以来古环境参数的研究[J].第四纪研究,1994,14(3):225-238.
[22]陈克造,BOWLER J M,KELTS K.四万年来青藏高原的气候变迁[J].第四纪研究,1990,10(1):21-31.
[23]余俊清,KELTS K.末次冰消期晚期青藏高原东北部气候变化[J].第四纪研究,2002,22(5):413-423.
[24] AN Z,COLMAN S M,ZHOU W,et al. Interplay between the Westerlies and Asian monsoon recorded in Lake Qinghai sediments since 32 ka[J]. Scientific Reports,2012,2(8):619.
[25]王苏民,施雅风.晚第四纪青海湖演化研究析视与讨论[J].湖泊科学,1992,4(3):1-9.
[26]曾承.青海湖碳酸盐氧同位素环境记录再认识[J].盐湖研究,2007,15(1):16-19.
[27]赵存法,鹿化煜,周亚利,等.青海湖地区冰消期以来气候变化的黄土记录[J].高校地质学报,2009,15(1):135-140.
[28]刘兴起,王苏民,沈吉.青海湖QH-2000钻孔沉积物粒度组成的古气候古环境意义[J].湖泊科学,2003,12(2):112-117.
© 2004-2018 中国地质图书馆版权所有 京ICP备05064691号 京公网安备11010802017129号 地址：北京市海淀区学院路29号 邮编：100083 电话：办公室：(+86 10)66554848；文献借阅、咨询服务、科技查新：66554700 |