Knowledge Resource Center for Ecological Environment in Arid Area
| 罗布泊全新世环境变迁 | |
| 贾红娟 | |
| 出版年 | 2010 |
| 学位类型 | 博士 |
| 学位授予单位 | 中国科学院大学 |
| 中文摘要 | 罗布泊干旱脆弱的生态环境对气候变化和人类活动非常敏感，是研究区域环境变化的理想载体。揭示罗布泊环境变迁，对提高干旱区应对全球变化能力和完善干旱区可持续发展理论有直接借鉴意义。由于罗布泊特殊恶劣的地理环境，前人虽然对罗布泊环境变迁开展了一些研究，但干旱核心区全新世环境演变过程并没有得到很好认识，甚至对楼兰地区沉积地层的性质和时代都众说纷纭，缺少实测数据的支持，对罗布泊全新世时期最大的覆盖面积和水量也没有任何说法。因此基于罗布泊地区全新世研究薄弱的现状，本文利用楼兰佛塔剖面和东湖湖心剖面作为研究对象，采用释光和AMS-14C测年结果建立年代标尺，通过分析两个剖面的沉积学特征、地球化学特征、生物学特征，探讨了罗布泊地区早中全新世古气候、古环境演化历史，对该区早期人类活动、湖泊规模进行了初步分析，得到以下初步认识：1 楼兰湖相地层沉积时代为全新世，说明全新世期间罗布泊面积较大，曾到达楼兰地区，全新世期间楼兰地区有过两次沉积间断，指示罗布泊地区干旱加剧、湖泊萎缩，全新世适宜期环境相对湿润，但也存在多次气候波动。根据剖面粒度、主量元素、碳氮分析结果可把罗布泊地区气候演化划分为8个时段：①10.84-10.13kaB.P.( 6-4.65 m)气候湿润。②10.13-7.45 kaB.P.沉积间断，气候干旱③7.45-7.21kaB.P.(4.65-4.15m)气候较干旱，波动明显。④7.21-6.98 kaB.P. (4.15- 3.70m)气候湿润，波动明显。⑤6.98-5.95kaB.P(3.70-1.85m)气候较干旱。其间有过两次湿润事件分别在6.48 kaB.P.(2.75m)、6.22 kaB.P.(2.25m)附近。⑥5.95-5.34kaB.P (1.85-0.95m)气候相对上一阶段湿润，在5.37 kaB.P.(1m)左右出现一次洪水事件。⑦5.34-4.93kaB.P.(0.95-0.35m)和上一阶段相比干旱，波动明显。⑧4.93-4.69kaB.P. (0.35-0m) 气候相对上一阶段湿润。\n2 东湖湖心孢粉结果显示早全新世罗布泊流域有过耕作活动，耕作活动的出现与消亡受气候变化控制，耕作活动出现在气候湿润时期，干旱时耕作活动消失。\n3 罗布泊“大耳朵”干盐壳在四千年前可能已形成，西湖新湖区可能无沉积间断，亦或其沉积物为后期沉积。\n4 现代地形条件下全新世时期罗布泊水域面积曾达11900km2，最大湖盆容积可达4262×107m3。 |
| 英文摘要 | Lop Nur is an extremely fragile and climatically sensitive region that preserves a complex history of Holocene environmental change. It is relevant to study past records to understand how regional environmental changes are related to the Earth's climate system changes. There were a little research about environmental changes of the Lop Nur, but the process of Holocene environmental changes is not well recognized. The time of the lacustrine deposits is not determined. Previous research involved in a little about what result in agriculture appears or collapse. The maximum water volume of the Lop Nur at Holocene has not yet studied.This study selects Lop Nur sediment as the research object. Multi-proxy was researched to explore the early to middle Holocene climate and environmental evolution, agricultural activities, lake scale. The main conclusions obtained in this study are as follows:\n1 The lacustrine sedimentary time of Loulan stupa section is Holocene，Multi-proxy analysis results show early to middle Holocene climate was variable. Deglaciation time climate was relatively humid. Comparison to previous and posterior hiatus, the mid-Holocene climate was relatively wet, but still displayed high-frequency, high-amplitude fluctuations. Multi-proxy analysis results show climatic can be divided into eight phase\n ① 10.84-10.13kaB.P. (6-4.65m) Climate was humid\n ② 10.13-7.45 kaB.P. Climate was drought\n ③ 7.45-7.21 kaB.P. (4.65-4.15m) Climate was drought and fluctuated significantly.\n ④ 7.21-6.98kaB.P. (4.15-3.70 m) Climate was humid and fluctuated significantly \n ⑤ 6.98-5.95kaB.P. (3.70 -1.85m) Climate was drought\n ⑥ 5.95-5.34kaB.P (1.85-0.95m) Climate was relatively humid than previous phase\n ⑦ 5.34-4.93kaB.P.(0.95-0.35m) Climate was drought\n ⑧ 4.93-4.69kaB.P. (0.35-0 m) Climate was at relatively humid phase.\n2 Pollen data demonstrate that early to middle Holocene there have been agricultural activities at Lop Nur region. Environmental or climatic shifts often result in agriculture appear or collapse. At humid phase agricultural activities emerge. At drought phase agricultural activities die.\n3 Lop Nur dry salt crust may have formed at the 4000 aB.P.The new lake has no depositional break or the sediment is deposited later.\n4 During Holocene Lop Nur has been reached 11900km2, the entire lake volume up to 4262 × 107m3. |
| 中文关键词 | 罗布泊 ; 全新世 ; 环境变迁 ; 人类活动 ; DEM |
| 语种 | 中文 |
| 国家 | 中国 |
| 来源学科分类 | 第四纪地质学 |
| 来源机构 | 中国科学院地质与地球物理研究所 |
| 资源类型 | 学位论文 |
| 条目标识符 | http://119.78.100.177/qdio/handle/2XILL650/286837 |
| 推荐引用方式 GB/T 7714 | 贾红娟. 罗布泊全新世环境变迁[D]. 中国科学院大学,2010. |
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