共查询到20条相似文献，搜索用时 15 毫秒
1.
南海北部中新世以来粘土矿物特征及东亚古季风记录 总被引：4，自引：0，他引：4
应用X射线衍射(XRD)、扫描电子显微镜(SEM) 和X射线能谱(EDS) 分析技术对南海北部ODP1146站中新世以来(~20 Ma) 粘土矿物的组成、结晶学特征、微形貌和化学成分进行了研究, 分析了粘土矿物的物质来源及其记录的东亚季风演化历史.1146站粘土矿物组合的总体特点是以伊利石和蒙脱石为主, 高岭石和绿泥石含量较低.物源分析表明, 1146站蒙脱石主要来自于吕宋岛, 伊利石和绿泥石来自于珠江和台湾(长江), 而高岭石则主要来自于珠江.1146站的粘土矿物不仅被南海周围物源的同时代气候所控制, 而且为相互消长的不同传输作用(表层洋流) 的强度所影响.1146站(伊利石+绿泥石) /蒙脱石比值可以用来作为东亚季风演化的矿物学标志.指标变化显示出东亚冬季风强度和冬季风相对夏季风的强度在15 Ma、8 Ma和3 Ma左右发生了3次显著加强, 结果可以与黄土、北太平洋风尘沉积、南海微体古生物记录等很好对比.青藏高原的阶段性隆升可能促进了东亚季风的这3次加强. 相似文献
2.
运用伊利石结晶度线性剥离法,定量计算了华南、台湾和吕宋这 3 个主要物源区对南海北部陆坡MD12-3432和MD12-3434两个岩芯(分别为50. 80 m和8. 33 m)MIS 2期粘土相对贡献量的时间序列变化.结果显示,台湾对两个岩芯的贡献最大(36%~62%),吕宋的贡献次之(28%~50%),二者之和一般大于90%,而来自华南的贡献最小(3%~17%).台湾和吕宋的贡献量呈现显著反向的千年时间尺度快速波动,二者贡献量随东亚夏季风增强或减弱而显著变化,因此,吕宋/台湾贡献量比值可以用于指示东亚夏季风的快速演化.吕宋/台湾粘土贡献量比值在B?lling-Aller?d和Dansgaard-Oeschger 2事件期间的增加,反映了同时期东亚夏季风的快速增强;而在Heinrich 1和Heinrich 2事件期间的减小,则指示了东亚夏季风的减弱.吕宋/台湾贡献量比值对东亚夏季风快速变化的指示,在一定程度上要明显优于蒙脱石/(伊利石+绿泥石)比值.南海北部MIS 2期粘土矿物对东亚夏季风快速变化的响应具有明显的空间差异性,受洋流搬运扰动和物源控制作用影响,陆坡相对浅水区粘土矿物记录的东亚夏季风快速变化信息相对有限,而深水稳定的沉积环境则更有利于保存东亚夏季风快速变化信息. 相似文献
3.
对伊豆-小笠原海脊(ODP 782A孔)上新世以来沉积物中黏土矿物的组成、含量及矿物学特征进行了分析,结果表明:黏土矿物以伊利石(42%)和蒙皂石(42%)为主,绿泥石的平均含量为14%,高岭石的含量最低,平均仅为2%。伊利石的结晶度较好,平均为0.25°Δ2θ;化学指数较低,平均为0.31;表明伊利石主要形成于干冷的气候环境。通过将ODP 782A孔黏土矿物组合特征和含量与周边可能源区对比,并结合伊利石和蒙皂石的矿物学参数特征,我们认为蒙皂石主要来源于伊豆-小笠原海脊周边岛弧火山物质;伊利石、绿泥石和高岭石主要来自亚洲大陆风尘。上新世以来(伊利石+绿泥石)/蒙皂石比值总体上呈增加的趋势,并且在5.3~3.6、3.6~1.6、1.6~0 Ma的三个阶段表现出不同的变化特征,该比值与全球深海δ18O值所记录的全球变冷、北太平洋ODP 885/886孔风尘通量和灵台黄土沉积速率,以及日本海U1430站伊利石/蒙皂石比值所指示的亚洲内陆干旱变化的总体变化趋势和阶段性变化的时间点大致同步,表明该比值敏感地响应了全球变冷和亚洲内陆的干旱。上新世以来(伊利石+绿泥石)/高岭石比值表现为高/低交替变化,分别与中国灵台黄土磁化率高/低变化相对应,由于黄土磁化率记录了亚洲内陆干/湿变化,因此该黏土矿物比值敏感地响应了亚洲内陆的古气候变化,因而可以作为可靠的亚洲大陆干/湿变化示踪指标。 相似文献
4.
浙闽泥质区是全新世高海平面以来沉积物的汇。受东亚季风影响,浙闽沿岸流和台湾暖流具有季节性变化,长江口"夏储冬输"的沉积物输运模式对东海内陆架泥质区的形成有关键作用。浙闽泥质区的潜在物源主要有长江、浙闽河流以及台湾西部山地河流,以长江物质为主。黏土矿物、稀土元素、Sr-Nd同位素、环境磁学等方法是物源研究的重要手段。长江物质以伊利石为主,蒙脱石含量较少,高岭石和绿泥石含量中等;而台湾物质以伊利石和绿泥石为主,没有蒙脱石。磁黄铁矿是台湾河流沉积物特有的磁性矿物,可作为大陆河流与台湾河流物源识别的指标。泥质区位于东亚季风区,受低纬热带过程和高纬大气环流的影响,气候变化具有波动性。沉积物敏感粒级反演的东亚冬季风（EAWM）只记录了泥质区形成以来的气候变化,不能代表整个全新世。受台湾暖流和浙闽沿岸流的双重影响,敏感粒级作为EAWM演化的指标需进一步深入研究。 相似文献
5.
对南海北部大洋钻探ODP1 1 48站进行稳定同位素和有孔虫分析 ,采用多种替代性指标 ,追溯上新世晚期以来东亚冬季风的演变。发现约 3 1～ 2 2MaB .P .之间 ,浮游有孔虫Globigerinoidesruber的δ13C值显著降低 ,而Neogloboquadrinadutertrei的相对丰度明显增大 ,指示冬季风急剧增强 ,并伴随表层海水温度的降低和古生产力的增高。此后 ,冬季风还有几次明显的增强 ,特别是在约 1 7MaB .P .,1 .3MaB .P .,0 .9MaB .P .,0 .6MaB .P .和0 2MaB .P .。 相似文献
6.
沉积物颜色和粘土矿物对库车坳陷第三纪气候变化的指示 总被引：5，自引：0，他引：5
库车坳陷第三纪连续的碎屑沉积,记录了丰富的古环境与古气候变化的信息。在详细的磁性地层年代学基础上,对库车坳陷北部第三系沉积剖面进行了系统的沉积物颜色测定和粘土矿物分析。结果表明,库车坳陷第三纪沉积物颜色变化与全球第三纪温度的变化有一致的趋势,随着全球气温的降低,沉积物的颜色的红色指数降低。粘土矿物的组合和含量变化在13 M a出现了一个转折,在此之前,库车坳陷泥岩样品中的粘土矿物组合为伊利石和绿泥石,指示干旱的气候环境。在13 M a之后,库车坳陷的粘土矿物组合变为蒙脱石、高岭石、绿泥石和伊利石,指示干冷与温湿交替的气候环境,与亚洲内陆季风气候加强相对应。由此,可以认为库车坳陷第三纪13M a的气候变化与青藏高原的隆升密切相关。 相似文献
7.
Chemical weathering in Luzon, Philippines from clay mineralogy and major-element geochemistry of river sediments 总被引：3，自引：0，他引：3
Zhifei Liu Yulong Zhao Christophe Colin Fernando P. Siringan Qiong Wu 《Applied Geochemistry》2009,24(11):2195-2205
Clay mineralogy and major-element geochemistry of 35 surface sediment samples collected in 21 major to moderate rivers of Luzon, Philippines are used to evaluate the present chemical weathering process. The clay mineral assemblage consists mainly of smectite (average 86%) with minor kaolinite (9%) and chlorite (5%) and very scarce illite (1%), and does not show strong island-wide differences. The major element results of both bulk and clay-fraction sediments indicate that the formation of clay minerals is accompanied by leaching of Ca and Na first and of Fe and Mn thereafter during the chemical weathering process. A low-moderate chemical weathering degree of bulk sediments and a moderate-intensive degree of clay-fraction sediments are obtained in Luzon rivers based on proxies of chemical index of alteration (CIA) and smectite crystallinity. It is suggested that the majority of andesitic–basaltic volcanic and sedimentary rocks along with the tectonically active geological setting and sub-tropical East Asian monsoon climate are responsible for the predominance of smectite in the clay mineral assemblage. 相似文献
8.
南海渐新世以来粘土矿物的演变特征及意义 总被引：14，自引：1，他引：13
通过对南海北部ODP184航次1148站32.8Ma以来深海沉积物中粘土矿物组成及其变化特征的分析,发现以15.5Ma为界,下部沉积物粘土矿物组成中蒙脱石含量高达70%,上部则以伊利石和绿泥石逐步增高、蒙脱石含量明显下降为特征,揭示出该区深海沉积物中粘土矿物演变可以分为32.8～15.5Ma的构造控制期和15.5Ma以来的气候控制期。在构造控制期,粘土矿物成分记录了南海扩张演变的历史;而在气候控制期,粘土矿物特征除反映出南海北部周边总体降温的过程外,还显示了3Ma的突然降温,与该站底栖有孔虫氧同位素资料反映的全球气候变化具有很好的对比性。 相似文献
9.
应用X射线衍射(XRD)对南海北部陆架海域225个站位表层沉积物黏土组分进行分析,结果表明,研究区黏土矿物总体以伊利石和绿泥石为主,高岭石和蒙脱石质量分数少,绿泥石、高岭石与蒙脱石质量分数呈明显的负相关关系。根据南海北部陆架海域表层沉积物中黏土矿物空间分布特征,结合邻近河流的黏土矿物组分以及洋流搬运作用,雷州半岛东部海域伊利石主要来源于广东沿海河流和珠江,绿泥石来自台湾岛,蒙脱石主要由吕宋河流提供,高岭石则由广东沿海河流和海南岛入海河流提供;雷州半岛西部海域伊利石来源于珠江,绿泥石和高岭石由红河提供,蒙脱石可能受广西入海河流携带的沉积物影响。 相似文献
10.
Clay mineral sedimentation in high northern latitude deep-sea basins since the Middle Miocene (ODP Leg 151, NAAG) 总被引：10，自引：0，他引：10
A. Winkler T. Wolf-Welling K. Stattegger J. Thiede 《International Journal of Earth Sciences》2002,91(1):133-148
High-resolution clay mineralogical investigations and their comparison with other sedimentological data from ODP Sites 908 and 909 (central Fram Strait) were used to reconstruct the paleoclimate and paleoceanography in the high northern latitudes since the Middle Miocene. Ice rafting has probably occurred since 15 Ma. The comparison of sand-sized components and clay mineral distribution demonstrate that both were not delivered by the same transport process. The input of the clay fraction is related to transport through sea ice and/or oceanic currents. A provenance change at 11.2 Ma is indicated by variations within clay mineral distribution and increased accumulation rates. This is interpreted as a result of an increase in water mass exchange through the Fram Strait. Decreases of the smectite to illite and chlorite ratio at Site 909 suggest a Middle Miocene cooling phase between 14.8 and 14.6 Ma, and a further cooling phase between 10 and 9 Ma. The intensification of glaciation in the Northern Hemisphere is documented by an increase of illite and chlorite from 3.4 to 3.3 Ma, which is synchronous to the onset of major Northern Hemisphere glaciation as indicated by oxygen isotope data. 相似文献
11.
Climate evolution associated with the uplift in Gyirong, southern margin of the Tibetan plateau, was investigated based on
the clay mineralogy of the Gyirong sediments, using X-ray diffraction and scanning electron microscopy methods. The (chlorite + illite)/(kaolinite + smectite)
ratio and the illite crystallinity index suggest the trend of paleoclimate evolution in Gyirong basin during ~7–1.7 Ma BP,
with a warm and humid climate in ~7.0–5.8 Ma, a relative cool and dry climate in ~5.8–5.5 Ma, a relative warm and humid climate
in ~5.5–2.5 Ma, and a much warmer climate in ~2.5–1.7 Ma, respectively. The fluctuating kaolinite/smectite index and calcite
content and the frequent occurrence of gypsum in the episode of ~6.7–5.5 Ma suggest intense climatic fluctuations between
humid and more seasonal humid conditions. Five peaks exhibit at 5.8, 4.9, 4.3, 3.6, and 2.5 Ma in the curves of illite and
chlorite content and illite crystallinity. The intense uplift and tectonic-forced cooling at ~5.8 and 4.3 Ma were indicated
by the high-illite crystallinity index and illite and chlorite content. A remarkable increase in illite and chlorite content
associated with only little increase in illite crystallinity at ~3.6 Ma indicates a rapid uplift, but no significant climate
change. And a sharp increase in illite crystallinity, while small change in illite and chlorite content at ~2.5 Ma suggests
that no remarkable relief was produced by the uplift, which may take place in the whole south Tibet plateau, while cooling
at 4.9 Ma is probably a record of the global climate cooling. 相似文献
12.
台湾海峡表层沉积物中黏土矿物特征及物质来源 总被引：4，自引：1，他引：3
利用X射线衍射仪,对比分析台湾海峡及周边表层沉积物的黏土矿物特征,讨论长江、福建和台湾河流对海峡黏土矿物的贡献程度。福建河流（闽江）的黏土矿物以高岭石为主（>40％）,其次是伊利石（30％）和绿泥石,不含蒙脱石;长江和浙闽泥质区的黏土矿物特征是伊利石含量最高（61％～66％）,其次是绿泥石（16％～17％）和高岭石（10％～13％）,少量蒙脱石（6％～9％）。台湾河流（浊水溪）黏土矿物组合为伊利石（>70％）和绿泥石,不含高岭石和蒙脱石为特征。台湾海峡高岭石含量由西向东明显减少,说明高岭石主要来自福建的河流。〖JP2〗台湾海峡50 m等深线以东区域的黏土矿物具有高的伊利石和绿泥石含量,低的蒙脱石和高岭石含量,且伊利石的化学指数和结晶度值都明显低于长江和福建的河流,反映台湾河流的物质来源。在台湾暖流作用下,台湾河流为台湾海峡中北部提供了大量的伊利石和绿泥石。福建近海的黏土矿物主要是由福建河流提供的,但在平潭岛周边海域的黏土矿物可能有长江物质的混合。〖JP〗 相似文献
13.
西昆仑山前陆盆地粘土矿物特征及其地质意义 总被引：1，自引：0，他引：1
为重建西昆仑山地区晚新生代的地质构造及环境演变过程,本文利用X射线衍射（XRD）及扫描电子显微分析（SEM）方法,对西昆仑山前陆盆地（叶城盆地）该时期沉积的一套磨拉石建造中的粘土矿物进行了研究。结果表明,在整个晚中新世到早更新世的沉积物地层中,粘土矿物的种类始终以伊利石和蒙脱石为主,含少量的绿泥石和高岭石。但伊利石、蒙脱石、高岭石的相对含量,以及伊利石结晶度值等均显示出明显的变化。在8~3.5 Ma B.P.期间,伊利石相对含量值和结晶度值均比较高,而蒙脱石相对含量低,并有少量的高岭石产出;在3.5~3.3 Ma B.P.期间,伊利石相对含量值和伊利石结晶度值均急剧降低,而相反,蒙脱石相对含量值急剧升高,高岭石基本消失;3.3~2.8 Ma B.P.期间沉积物的粘土矿物参数与8~3.5 Ma B.P.时期的粘土矿物参数非常接近;而2.8~1.8 Ma B.P.期间沉积物的粘土矿物参数则与3.5~3.3 Ma B.P.期间的粘土矿物参数相类似。根据沉积物中的粘土矿物特征变化规律可以推断,物源区母岩成分的变化是粘土矿物特征变化的主要原因,古气候古环境变化则是次要影响因素。粘土矿物特征的变化规律显示西昆仑山体在晚新生代具有不均匀的阶段性隆升的特点,在3.5 Ma B.P.、3.3 Ma B.P.、2.8 Ma B.P.左右分别发生了三次明显的构造隆升事件,而且总伴随着风化母岩成分的变化。物源区在早更新世中期（12.5 Ma B.P.)很可能处于干旱的古气候古环境中。 相似文献
14.
晚中新世以来亚洲季风阶段性演化的海陆记录 总被引：4，自引：0，他引：4
本文在综合对比晚新生代以来中国黄土高原黄土一红粘土沉积、西北太平洋粉尘沉积、南海有孔虫、阿拉伯海有孔虫记录的基础上,探讨了大约8Ma以来亚洲季风的阶段性演化历史。结果发现,黄土高原粉尘沉积在8Ma前后大规模出现,在3．5Ma前后大幅增加;印度季风在8Ma前后形成(或显著加强);南海ODP1146站位浮游有孔虫Neoglcboquadrina丰度也有两次明显增加,表明海水表面温度不断降低和海洋生产力的增加,指示东亚冬季风作用增强。北太平洋()DP885／886钻孔风成粉尘通量也有增加,指示亚洲内陆进一步的干旱化和冬季风作用的增强。印度洋沉积通量在11Ma前后开始增加。在9～8Ma时出现峰值,表明喜马拉雅山和青藏高原南部逐渐隆起。当隆起达到足够高度时,导致亚洲内陆干旱气候带扩大,同时提供大量粉尘并向东传输到中国北方和北太平洋地区。青藏高原北缘山前盆地的沉积记录显示,在3．6Ma时,高原北部的进一步快速隆升过程可能影响到整个高原,从而导致亚洲内陆更加干旱化,东亚季风增强,粉尘沉积加快,南海及印度洋陆源沉积作用加剧。 相似文献
15.
Kamlesh Verma Sanjeeb Bhattacharya P. Biswas Prakash K. Shrivastava Mayuri Pandey N. C. Pant IODP Expedition Scientific Party 《International Journal of Earth Sciences》2014,103(8):2315-2326
Core U1359 collected from the continental rise off Wilkes Land, east Antarctica, is analyzed for the clay mineralogy and carbon content. The temporal variation of the clay mineralogical data shows a dominance of illite with chlorite, smectite and kaolinite in decreasing concentration. Clay mineral illite is negatively correlated with smectite which shows enrichment during 6.2–6.8, 5.5–5.8, 4.5 and 2.5 Ma. The mineralogical analyses on the silt size fraction (2–53 μm) of some selected samples were also carried out. The combined result of both the size fractions shows the presence of chlorite and illite in both size fractions, smectite and kaolinite only in clay size fraction (<2 μm) and similarity in the crystallinity and chemistry of illite in both fractions. Similar nature of illite in both fractions suggests negligible role of sorting probably due to the deposition from the waxing ice sheet. During times of ice growth, nearby cratonic east Antarctica shield provided biotite-rich sediments to the depositional site. On the other hand, the presence of smectite, only in the clay size fraction, suggests the effective role of sorting probably due to the deposition from distal source in ice retreat condition. During times of ice retreat, smectite-rich sediment derived from Ross Orogen is transported to the core site through surface or bottom water currents. Poor crystallinity of illite due to degradation further corroborates the ice retreat condition. The ice sheet proximal sediments of U1359 show that in the eastern part of Wilkes Land, the ‘warming’ was initiated during late Miocene. 相似文献
16.
采用X射线衍射、扫描电镜分析方法,对兰州盆地永登剖面晚古新世—早渐新世沉积物中粘土矿物的相对含量、伊利石结晶度、显微形貌及其古气候意义进行深入研究。结果表明:晚古新世—早渐新世沉积物中粘土矿物主要为伊利石、蒙脱石、绿泥石和少量的坡缕石,其中伊利石的含量最高,而且从晚古新世到早渐新世,沉积物中伊利石的含量呈明显升高的趋势,蒙脱石则呈明显减少的趋势;在大约55 Ma处伊利石含量急剧减小,而蒙脱石含量急剧增大。此外,可见到毛发状的自生坡缕石沿蒙脱石晶片边缘交代生长,而碎屑成因的坡缕石则主要呈破碎的短棒状。粘土矿物分布特征表明,兰州盆地晚古新世—早渐新世的古气候以干旱为主导,并且经历了由相对温暖湿润到半干旱半湿润或干旱炎热的转变,这种气候转型主要受全球气候的影响,即受行星风系的控制;而在大约55 Ma处伊利石、蒙脱石的含量变化则记录了全球性的PETM事件。 相似文献
17.
We analyzed the clay mineral assemblages, content and mineralogical characteristics of Hole U1438A sediment recovered from Amami Sankaku Basin during International Ocean Discovery Program (IODP) expedition 351. The results show that the clay minerals are mainly composed of illite (average 57%), smectite (average 26%), chlorite (average 14%) and minor kaolinite(average 3%). The crystallinity of illite in all samples are good (<0.4 Δ° 2θ), and the chemical indexes of illite in all samples are low (<0.4). Both indicate that illite in Hole U1438A formed in cold and dry climate. By comparing clay mineral assemblages of hole U1438A and the potential sediment sources, we suggest that smectite be mainly derived from the volcanic materials around Amami Sankaku Basin. Illite, chlorite and kaolinite are mainly derived from the Asian dust. The ratios of (illite+chlorite)/smectite show a phased increase over the last 350 ka, which is consistent with the cold and drying trend of the Asian continent since late Pleistocene. The high ratios of (illite+chlorite)/smectite and (illite+chlorite)/kaolinite during glacial period indicate that much more Asian dust was input into the Amami Sankaku Basin, which are responded to the aridity of Asian continent and strengthened east Asian Monsoon during glacial period. 相似文献
18.
19.
运用X射线衍射分析技术，计算了成岩带、近变质带粘土矿物C^*方向的粒度。根据阿尔卑斯造山带前陆碎屑岩粘土矿物粒度与伊利石结晶指数的关系，推导出了伊利石、绿泥石、蒙脱石、伊蒙混层、高岭石和叶蜡石的c^*方向粒度变化趋势曲线。结果表明，大多数产于成岩带和近变质带的粘矿物其c6*方向粒工为几至几十纳米。成岩带和近为质带是一维天然纳为级土帮物的产地。 相似文献
20.
Richard H. April 《Sedimentary Geology》1981,29(4):283-307
The clay mineralogy of the Newark Supergroup (Upper Triassic/Lower Jurassic) in the Connecticut Valley was studied by X-ray diffraction analysis. Clay minerals identified in 126 samples are illite, chlorite, smectite, kaolinite, vermiculite, expandable chlorite, mixed-layer illite/smectite, mixed-layer chlorite/smectite, and mixed-layer chlorite/vermiculite. In general, the rocks are illitic with subordinate amounts of chlorite. However, the various lithofacies in the Newark Supergroup are characterized by distinct clay-mineral assemblages. Red beds of floodplain origin contain clays mainly of detrital nature with 2M illite most abundant. Subordinate amounts of chlorite, smectite, vermiculite, kaolinite and mixed-layer illite/smectite are also present. An interstratified chlorite/vermiculite occurs in red mudstone underlying basalt flows. Lacustrine gray beds are generally characterized by the clay-mineral assemblage 1Md illite + chlorite with minor amounts of smectite ane expandable chlorite. An interstratified chlorite/smectite predominates in gray mudstone associated with perennial lake cycles in the East Berlin Formation. Black shales of deeper lacustrine origin contain the assemblage 1Md ifillite + trioctahedral smectite and traces of chlorite. Illite and smectite also occur as mixed-layer phases.In many respects, the distribution of clay minerals in the Connecticut Valley can be likened to the general scheme proposed for the Permo-Triassic basins of Europe and Africa. These display both vertical and horizontal variations in clay-mineral assemblages that reflect the chemical and spatiotemporal evolution of intrabasin depositional and diagenetic environments. Chemical data indicate that magnesium, especially, was concentrated in the black muds of large perennial lakes that intermittently occupied the Connecticut rift valley. Pore waters derived from these sediments played an important role in the development of Mg-rich 2 : 1 and interstratified clay minerals during early diagenesis. 相似文献