岷江上游近两万年前发生了什么事件?
|
摘要
在对岷江1933年叠溪古镇地震滑坡调查研究中,对较场大滑坡上覆盖的较古老的土黄色厚土层进行详细研究,发现并确认这是一套静水环境下的河湖相沉积物,定名为叠溪古堰塞湖相沉积。这套湖相沉积物厚度最大可达200余m,根据14C测试,形成于约两万年以前。此后在叠溪下游以及岷江支流杂谷脑河中又发现了几个古堰塞湖沉积物,测年初步判定,也都形成于距今两万年左右。这一事实揭示两万年以前岷江上游曾发生过一次重大的变动,系列堰塞湖几乎在同一时期出现,形成了特殊的生态环境,消亡过程必然对其下游乃至川西平原环境的演化发生重要影响。堰塞湖沉积物中记载了地质环境和古气候环境变化的信息,是深入系统研究青藏高原前缘地质环境近期演化规律的极为可贵的资料。文中对这些古堰塞湖作了简要介绍,并就一些主要问题进行初步讨论。
A huge natural paleo-dammed lake deposit named “Diexi paleo-dammed lake” in Diexi ancient county was discovered in 1999. It is situated above the basin of the upper Minjiang River in Sichuan Province, China. The thickness of this lacustrine deposit is variable, reaching up to 200 m at some locations. Carbon-14 chronology has shown that this lacustrine deposit was formed about 20 000 years ago. Subsequently, other smaller paleo-dammed lake deposits have been discovered downstream of the Diexi area above the basin of Zagunao River (a tributary of Minjiang River). According to our geological analysis and chronometry results, they were formed around the same period as the “Diexi paleo-dammed lake”. Based on these discoveries, we believe that there were important geographical changes happening in the region around that time, which resulted in a series of barrier lakes, which must have brought environmental changes to this area. The outburst of these dammed lakes and their eventual dying out, could have played an important role in the subsequent change of the environment in the region of Minjiang River, as well as the western Sichuan basin.In addition, paleo-dammed lake lacustrine sediments left a significant and important record of change in the paleo-environment and paleoclimate of the area, which are also invaluable in studying the evolutionary process of the regional geo-environment at the eastern side of the Qinghai-Tibet altiplano.The discovery of these paleo-dammed lakes and related problems are introduced and discussed in this paper.
A huge natural paleo-dammed lake deposit named “Diexi paleo-dammed lake” in Diexi ancient county was discovered in 1999. It is situated above the basin of the upper Minjiang River in Sichuan Province, China. The thickness of this lacustrine deposit is variable, reaching up to 200 m at some locations. Carbon-14 chronology has shown that this lacustrine deposit was formed about 20 000 years ago. Subsequently, other smaller paleo-dammed lake deposits have been discovered downstream of the Diexi area above the basin of Zagunao River (a tributary of Minjiang River). According to our geological analysis and chronometry results, they were formed around the same period as the “Diexi paleo-dammed lake”. Based on these discoveries, we believe that there were important geographical changes happening in the region around that time, which resulted in a series of barrier lakes, which must have brought environmental changes to this area. The outburst of these dammed lakes and their eventual dying out, could have played an important role in the subsequent change of the environment in the region of Minjiang River, as well as the western Sichuan basin.In addition, paleo-dammed lake lacustrine sediments left a significant and important record of change in the paleo-environment and paleoclimate of the area, which are also invaluable in studying the evolutionary process of the regional geo-environment at the eastern side of the Qinghai-Tibet altiplano.The discovery of these paleo-dammed lakes and related problems are introduced and discussed in this paper.
引文
[1]Wang Lansheng,Yang Lizheng,Li Tianbin,et al.Evolution mechanism of Jiaochang earthquake landslide on Minjiang River and its controlling[J].Journal of Geological Hazards and Environment Preservation,2000,11(3):195-199(in Chi-nese).
[2]Wang Lansheng,Yang Lizheng,Wang Xiaoqun,et al.Dis-covery of huge ancient dammed lake on upstreamof Minjiang River in Sichuan,China[J].Journal of Chengdu University of Technology:Science&Technology Edition,2005,32(1):1-11(in Chinese).
[3]The Earthquake Bureau of Sichuan Province.The earthquake at Diexi in1933[M].Chengdu:Sichuan Science and Technol-ogy Press,1985(in Chinese).
[4]Li Chengsan,Wu Yansheng,Li Yongzhao,et al.The Quater-nary glacier historic relic of the Longmen mountain south seg-ment east braein Sichuan Province[G]∥The Chinese Quater-nary glacier historic relic research collection of corpus.Bei-jing:Science Press,1964:14-86(in Chinese).
[5]Wang Sumin,Zhang Zhenke.Progress in Chinese lacustrine deposit and environment evolvement research[J].Chinese Science Bulletin,1999,44(6):579-587(in Chinese).
[6]Shen Cai ming,Tang Lingyu,Wang Sumin,et al.RMaleurio spore records andits chronological list of Ruoergai Basin[J].Chinese Science Bulletin,2005,50(3):246-254(in Chinese).
[7]Wang Lansheng,Xu Xiangning,Wang Xiaoqun,et al.The investigate esti mate and programming report of geology his-toric relic sights about Diexi of Maoxian county[R].Cheng-du:Chengdu University of Technology,2005(in Chinese).
[1]王兰生,杨立铮,李天斌,等.四川岷江叠溪较场地震滑坡及环境保护[J].地质灾害与环境保护,2000,11(3):195-199.
[2]王兰生,杨立铮,王小群,等.岷江叠溪古堰塞湖的发现[J].成都理工大学学报:自然科学版,2005,32(1):1-11.
[3]四川地震局.一九三三年叠溪地震[M].成都:四川科学技术出版社,1985.
[4]李承三,吴燕生,李永昭,等.四川龙门山南段东坡及其山前带第四纪冰川遗迹[G]∥中国第四纪冰川遗迹研究文集.北京:科学出版社,1964:14-86.
[5]王苏民,张振克.中国湖泊沉积与环境演变研究的新进展[J].科学通报,1999,44(6):579-587.
[6]沈才明,唐领余,王苏民,等.若尔盖盆地RM孔孢粉记录及其年代序列[J].科学通报,2005,50(3):246-254.
[7]王兰生,许向宁,王小群,等.岷江叠溪地区地质遗迹景观调查评价与规划报告——四川省地质遗迹景观调查评价专题之一[R].成都:成都理工大学,2005.
[2]Wang Lansheng,Yang Lizheng,Wang Xiaoqun,et al.Dis-covery of huge ancient dammed lake on upstreamof Minjiang River in Sichuan,China[J].Journal of Chengdu University of Technology:Science&Technology Edition,2005,32(1):1-11(in Chinese).
[3]The Earthquake Bureau of Sichuan Province.The earthquake at Diexi in1933[M].Chengdu:Sichuan Science and Technol-ogy Press,1985(in Chinese).
[4]Li Chengsan,Wu Yansheng,Li Yongzhao,et al.The Quater-nary glacier historic relic of the Longmen mountain south seg-ment east braein Sichuan Province[G]∥The Chinese Quater-nary glacier historic relic research collection of corpus.Bei-jing:Science Press,1964:14-86(in Chinese).
[5]Wang Sumin,Zhang Zhenke.Progress in Chinese lacustrine deposit and environment evolvement research[J].Chinese Science Bulletin,1999,44(6):579-587(in Chinese).
[6]Shen Cai ming,Tang Lingyu,Wang Sumin,et al.RMaleurio spore records andits chronological list of Ruoergai Basin[J].Chinese Science Bulletin,2005,50(3):246-254(in Chinese).
[7]Wang Lansheng,Xu Xiangning,Wang Xiaoqun,et al.The investigate esti mate and programming report of geology his-toric relic sights about Diexi of Maoxian county[R].Cheng-du:Chengdu University of Technology,2005(in Chinese).
[1]王兰生,杨立铮,李天斌,等.四川岷江叠溪较场地震滑坡及环境保护[J].地质灾害与环境保护,2000,11(3):195-199.
[2]王兰生,杨立铮,王小群,等.岷江叠溪古堰塞湖的发现[J].成都理工大学学报:自然科学版,2005,32(1):1-11.
[3]四川地震局.一九三三年叠溪地震[M].成都:四川科学技术出版社,1985.
[4]李承三,吴燕生,李永昭,等.四川龙门山南段东坡及其山前带第四纪冰川遗迹[G]∥中国第四纪冰川遗迹研究文集.北京:科学出版社,1964:14-86.
[5]王苏民,张振克.中国湖泊沉积与环境演变研究的新进展[J].科学通报,1999,44(6):579-587.
[6]沈才明,唐领余,王苏民,等.若尔盖盆地RM孔孢粉记录及其年代序列[J].科学通报,2005,50(3):246-254.
[7]王兰生,许向宁,王小群,等.岷江叠溪地区地质遗迹景观调查评价与规划报告——四川省地质遗迹景观调查评价专题之一[R].成都:成都理工大学,2005.
版权所有：© 2023 中国地质图书馆 中国地质调查局地学文献中心