IOCAS-IR  > 海洋地质与环境重点实验室
北半球大冰期在菲律宾海北部的沉积响应
杨佳毅
Subtype硕士
Thesis Advisor蒋富清
2022-05-20
Degree Grantor中国科学院大学
Place of Conferral中国科学院海洋研究所
Degree Name理学硕士
Degree Discipline海洋地质
Keyword北半球大冰期,菲律宾海,黏土矿物,石英,物源
Abstract

北半球大冰期(约2. 73 Ma左右)全球的气候系统和地貌格局发生了显著变化,北半球高纬地区冰盖扩张并最终建立,地球由“单极有冰”变为“两极有冰”;全球气候也由上新世温暖的气候环境过渡到第四纪的“冰期-间冰期”气候。对于这样一个全球性的重要气候转型期在菲律宾海的沉积物中是否有记录目前仍缺乏研究。

本文选取菲律宾海北部DSDP 296孔和ODP 782A孔上新世以来的沉积物为研究对象,通过黏土矿物组成、含量及矿物学特征,石英单矿物的粒度组成特征的研究,识别了上新世以来DSDP 296孔和ODP 782A孔沉积物中黏土矿物和石英的来源;黏土矿物比值:如(伊利石+绿泥石)/蒙皂石和(伊利石+绿泥石)/高岭石,以及石英平均粒径和石英各端元众数粒径在北半球大冰期的变化,并与全球其他海陆地区的古气候记录对比,探讨菲律宾海北部沉积物如何响应北半球大冰期。

研究结果表明,ODP782A孔黏土矿物主要以蒙皂石(平均含量42%)和伊利石(42%)为主,绿泥石含量次之(14%),高岭石含量最低(2%)。伊利石结晶度较高(平均0.2°Δ2θ),化学指数为0.31,为富含铁镁的伊利石,形成于气候寒冷且水解作用较弱的陆地环境;ODP 782A孔中蒙皂石的含量远高于台湾岛和其他可能源区,而与伊豆-小笠原海脊附近火山岛弧较接近,表明蒙皂石主要笠原于火山岛弧;ODP 782A孔中伊利石的含量仅低于亚洲大陆和台湾岛,但是伊利石结晶度与台湾岛的不同,因此伊利石主要来源于亚洲大陆。绿泥石和高岭石的含量分别与伊利石的含量正相关,与蒙皂石负相关,且符合菲律宾海西北高,东南低的特征,表明绿泥石和高岭石也来源于亚洲大陆。DSDP 296孔石英单矿物的平均粒径为3.8μm,可以被分为超细粒( EM1)、细粒(EM2)、粗粒(EM3)和超粗粒(EM4)等四个端元。四个端元石英的众数粒径(从EM1EM4)分别为0.3μm3.2μm11μm26μm,含量变化范围分别为0-6%18-57%42-77%12-23 %EM2端元石英的众数粒径和含量与黄土高原由西风搬运的细粒风尘的众数粒径和含量类似、并且与济州岛、北太平洋、以及菲律宾海奄美三角盆地和帕西里-维拉海盆西风搬运的细粒风尘众数粒径和含量相似;EM3端元与奄美三角盆地粗粒端元风尘的众数粒径和含量相似,但是由于远距离输送,EM3端元比黄土高原和济州岛等由冬季风搬运的风尘众数粒径(15-16 μm)偏细。因此,可以推测这两个孔沉积物中EM2端元石英的主要来源是中国内陆干旱区的风尘,而搬运的动力可能主要是盛行西风,EM3端元石英的可能主要来源是中国内陆干旱区的风尘,而搬运的动力可能主要是东亚季风。

上新世以来,ODP 782A孔沉积物中(伊利石+绿泥石)/蒙皂石比值变化分为三个阶段:(15.3-3.6 Ma,该比值较稳定;(23.6-1.6 Ma,该比值略有增加,并呈现多个峰谷的变化;(31.6 Ma至今,该比值整体呈阶梯状增大。(伊利石+绿泥石)/蒙皂石比值在3.5 Ma2.7 Ma的显著增加与北极冰盖开始形成和最终建立的时间一致,表明该比值敏感地记录了全球气候变冷以及北半球冰盖的扩张。(伊利石+绿泥石)/高岭石比值呈现四个阶段性的变化,分别是5.3-3.6 Ma3.6-2.5 Ma2.5-0.7 Ma0.7 Ma-0,与黄土剖面磁化率所指示的东亚夏季风呈反向的变化,即该比值的高值与磁化率的低值相对应,说明该比值的高/低变化指示了亚洲内陆干/湿变化。该比值在3.6-2.5 Ma显著增加,说明此阶段由于北半球大冰期导致的亚洲内陆干旱,使得亚洲大陆向菲律宾海输入的陆源黏土增多,表明该比值响应于北半球大冰期的气候变化。

DSDP 296孔石英的平均粒径、EM2、EM3端元的众数粒径总体上呈增大的趋势,并可以分为四个阶段:5.3-3.6 Ma、3.6-2.5 Ma、2.5-0.9 Ma和0.9 Ma至今。上新世以来,石英的平均粒径、EM2和EM3端元石英众数粒径在约2.6 Ma,1.0 Ma同时增加,与上新世以来全球深海氧同位素的明显变重,北太平洋风尘通量、灵台黄土的沉积速率和风尘粒径,以及日本海伊利石/蒙皂石比值的增加基本一致。说明上新世以来北半球大冰盖的建立和中更新世全球气候转型,使亚洲内陆干旱气候持续和阶段性的加剧,并导致了盛行西风和东亚冬季风的加强。因此,DSDP 296孔石英平均粒径、EM2和EM3端元石英众数粒径的变化规律敏感地响应了北半球气候大冰期与中更新世气候变化。

Other Abstract

The global climate system and geomorphic pattern changed significantly during the Northern Hemisphere glaciation (about 2.73 Ma). Ice sheets expanded and eventually established in the high latitudes of the Northern Hemisphere, and the Earth changed from "unipolar ice" to "bipolar ice". The global climate also changed from the warm climate of Pliocene to the "glacial-interglacial" climate of Quaternary. Whether such a globally important climate transition has been documented in the sediments of the Philippine Sea remains unclear.

In this research, two Holes DSDP 296 and ODP 782A sediments in the northern Philippine Sea since Pliocene were selected for the research. Based on the composition, content and mineralogy of clay minerals and the grain size composition of quartz, the sources of clay minerals and quartz were identified. By comparing the timing of the variation of clay minerals ratios, such as, (illite+chlorite)/smectite and (illite+chlorite)/kaolinite ratios, the mean grain size of quartz and the contents of different endmember quartz with the Northern Hemisphere glaciation, and other global marine and terrigenous plaeoclimate records, the sedimentary response in the northern Philippine Sea to the Northern Hemisphere glaciation was addressed.

The results show that the clay minerals in Hole ODP 782A mainly consist of smectite (average 42%) and illite (42%), followed by chlorite (14%) and kaolinite (2%). The illite crystallinity and chemical index are relatively low (0.2° δ 2θ on average, and 0.31, respectively), which indicate that it was formed in the terrestrial environment with cold weather and weak hydrolysis. The content of smectite in Hole ODP 782A is much higher than that in Taiwan Island and other potential source areas, but close to the volcanic island arc near the Izu-Ogasawara Ridge, indicating that smectite mainly originated from the volcanic island arc. The content of illite in Hole ODP 782A is only lower than that in Asian interior and Taiwan island, but the of illite crystallinity is different from that of Taiwan Island, so illite mainly comes from Asia interior. The content of chlorite and kaolinite is positively correlated with the content of illite and negatively correlated with smectite, respectively, which is consistent with the characteristics of high in the northwest and low in the southeast of the Philippine Sea, indicating that chlorite and kaolinite also come from the Asian continent. The average grain size of Hole DSDP 296 quartz is 3.8 μm, which can be divided into four endmembers: ultra-fine-grained endmember (EM1), fine-grained endmember (EM2), coarse-grained endmember (EM3) and ultra-coarse-grained endmember (EM4). The mode sizes of the four end-member quartz (from EM1 to EM4) are 0.3 μm, 3.2 μm, 11 μm and 26 μm, respectively, and the content ranges from 0 to 6%, 18 to 57%, 42 to 77% and 12 to 23%, respectively. The mode grain size and content of EM2 quartz are similar to those of fine-grained Asian dust transported by the westerly wind on the Chinese Loess Plateau, the Cheju Island, the North Pacific Ocean, the Amami Sankaku Basin and the Parece-Vela Basin in the Philippines. The mode grain size and content of EM3 quartz are similar to that of coarse-grained end-member in the Amami Sankaku Basin, but finer than those (mode grain size at 15-16 μm) transported by east Asian winter monsoon in the Chinese Loess Plateau and Cheju Island due to long-distance transportation Therefore, it can be inferred that EM2 quartz in the two holes sediments was mainly derived from arid Asian continent , and was transported by the prevailing westerly wind. The EM3 quartz may be also derived from Asian interior, but transported by the East Asian winter monsoon.

Since Pliocene, the ratio of (illite+chlorite) / smectite in Hole ODP 782A has been changed in three stages: (1) 5.3-3.6 Ma, the ratio is stable; (2) 3.6-1.6 Ma, the ratio increased slightly and showed multiple peaks and valleys; (3) Since 1.6 Ma, the overall increase has been stepped. The significant increase of the (illite + chlorite)/smellite ratio at 3.5 Ma and 2.7 Ma coincides with the onset and eventual establishment of the Arctic ice sheet, suggesting that the ratio is sensitively respond to the global cooling and the expansion of the northern hemisphere ice sheet. The ratio of (illite + chlorite)/kaolinite changes in four stages, which are 5.3-3.6 Ma, 3.6-2.5 Ma, 2.5-0.7 Ma, and 0.7 Ma-0, respectively, which are opposite to the East Asian summer monsoon indicated by the magnetic susceptibility of the loess profile. In other words, the high value of the ratio corresponds to the low value of the magnetic susceptibility. This indicates that the high/low change of this ratio indicates the dry/wet change of Asia continent. The significant increase in the ratio between 3.6 and 2.5 Ma indicates that the terrigenous clay from the Asian continent to the Philippine Sea increased due to the aridity in the Asian interior during the Northern Hemisphere glaciation, indicating that the ratio is in response to the climate change during the Northern Hemisphere glaciation.

The mean grain size of Hole DSDP 296 quartz and the mode grain size of EM2 and EM3 quartz generally show an increasing trend, which can be divided into four stages: 5.3-3.6 Ma, 3.6-2.5 Ma, 2.5-0.9 Ma and 0.9 Ma to present. Since Pliocene, the mean grain size of quartz, the mode grain size of EM2 and EM3 quartz increased at 2.6 Ma, 1.0 Ma, which is synchronous with the heavier of global deep-sea oxygen isotope, increased dust flux in the north Pacific, and increased sedimentary rates and grain size of dust in the Chinese Loess, and the increase of illite/smectite ratio in Japan Sea. All of above evidences suggest that the establishment of the large ice sheets duringthe Northern Hemisphere glaciation and the middle Pleistocene transition  forced the continuous and periodic intensification of arid climate in Asian continent, and the intensification of prevailing westerlies and east Asian winter monsoon. The variation of the mean grain size of quartz in Hole DSDP 296 and the mode grain size of EM2 and EM3 quartz sensitively responded to the climate changes during the Northern Hemisphere glaciation and the Middle Pleistocene.

Subject Area海洋地质学
MOST Discipline Catalogue理学 ; 理学::海洋科学
Language中文
Table of Contents

1 引言... 1

1.1 研究背景与意义...1

1.2 研究现状... 2

1.2.1 北半球大冰期在全球不同区域的沉积响应... 2

1.2.2北半球大冰期的开始和持续的时间... 4

1.2.3北半球大冰期的主要示踪指标... 5

1.2.4 北半球大冰期的成因机制... 5

1.2.5 菲律宾海的古气候记录... 6

2 区域地质概况... 1

2.1 研究区位置及地形地貌... 1

2.2 研究区构造背景... 3

2.3 研究区沉积特征... 5

2.4 研究区水文特征... 6

2.5 研究区气象特征... 8

3 研究材料与方法... 10

3.1 研究材料... 10

3.2 地层年龄框架... 11

3.3 技术路线... 12

3.4 实验方法... 13

3.4.1碎屑组分分离..... 13

3.4.2黏土矿物分析..... 14

3.4.3 石英单矿物分析..... 15

4 菲律宾海北部黏土矿物的特征及物源分析... 17

4.1 黏土矿物组成... 17

4.2 黏土矿物含量、特征及变化... 18

4.3 黏土矿物的来源... 20

4.3.1 蒙皂石的来源..... 21

4.3.2 伊利石的来源..... 22

4.3.3 绿泥石的来源..... 23

4.3.4 高岭石的来源..... 23

5 菲律宾海北部石英的特征及物源分析... 25

5.1 石英的纯度... 25

5.2 石英的粒度组成特征... 25

5.2.1 ODP 782A孔石英粒度特征..... 25

5.2.2 DSDP 296孔石英粒度特征..... 29

5.2.3 ODP 782A孔与DSDP 296孔石英特征对比..... 34

5.3 石英的来源... 37

6 北半球大冰期在菲律宾海北部的沉积响应... 39

6.1黏土矿物对北半球大冰期的响应... 39

6.2 石英对北半球大冰期的响应... 42

7 结论... 44

参考文献... 45

... 54

作者简历及攻读学位期间发表的学术论文与研究成果... 56

Document Type学位论文
Identifierhttp://ir.qdio.ac.cn/handle/337002/178388
Collection海洋地质与环境重点实验室
Recommended Citation
GB/T 7714
杨佳毅. 北半球大冰期在菲律宾海北部的沉积响应[D]. 中国科学院海洋研究所. 中国科学院大学,2022.
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