鄂尔多斯盆地北部晚古生代沉积-构造格局及物源分析

综合研究鄂尔多斯盆地北部晚古生代发育背景、地层展布及岩性特征和沉积-构造格局,认为晚古生代沉积-构造格局主要受控于北缘兴蒙海槽演化,逐渐由东—西向转变为北东—南西向.结合前人对盆地北部晚古生代物源的研究成果,根据现今盆地北部构造特征,利用钻井和野外露头资料,对研究区晚古生代物源分布情况作了进一步探讨,初步建立起物源演化关系模式.研究表明:晚石炭世本溪期—早二叠世太原期,伊盟古隆起作为盆地北部物源而遭受剥蚀且具有一定的阻隔作用,使得阴山古陆可能并未向盆地北部提供物源;早二叠世山西期—晚二叠世石千峰期,伴随着伊盟古隆起地区开始接受沉积,阴山古陆成为盆地北部和北缘大青山地区的共同物源.     

柴西西岔沟剖面新生界碎屑锆石裂变径迹年龄对物源区构造活动的制约

对柴西西岔沟新生界碎屑锆石裂变径迹年龄的研究表明:沉积源区主要为遭受150～290 Ma热事件影响的阿尔金山带,在晚近纪晚期以后有古近系的加入;同时记录的发生于源区的构造热事件最早为海西早期,在海西中期有所加强,海西晚期之后至燕山早期为主要时期,尤以海西末-印支期最为鼎盛;在整个新生代源区抬升渐强、剥蚀加快.阿尔金断裂在8 Ma活动加强,在新近纪晚期表现为活动加剧,同名山系快速隆升,成为柴西主要物源区.柴西地区沉积源区在相对固定的态势下,也有一定分异性,即物源区的变更.古阿尔金断裂是存在的,随青藏高原内不同块体依次向北拼贴,且阿尔金断裂具有多阶段活动的特点.     

Activation of northern margin of the North China Craton in Late Paleozoic: Evidence from U-Pb dating and Hf isotopes of detrital zircons from the Upper Carboniferous Taiyuan Formation in the Ningwu-Jingle basin

LA-MC-ICPMS U-Pb dating has been performed on detrital zircons from the Upper Carboniferous Tai-yuan Formation (N-8) in the Ningwu-Jingle Basin, west of the North China Craton (NCC). The ages of 72 detrital zircon grains are divided into three groups: 303―320 Ma (6 grains), 1631―2194 Ma (37 grains, peaked at 1850 Ma), 2318―2646 Ma (29 grains, peaked at 2500 Ma). Detrital zircons of Group 2 and Group 3 were likely derived from the basement of the NCC. Group 1 zircons exhibit 176Hf/177Hf ratios ranging from 0...     

川西拗陷中段蓬莱镇组物源的地球化学示踪

探讨川西拗陷中段上侏罗统蓬莱镇组物源问题。采用地球化学示踪方法,通过岩石薄片、痕量元素和稀土元素等综合分析,结合前人的研究成果,对蓬莱镇组源区背景属性和物源特征进行研究。结果表明:研究区蓬莱镇组砂岩碎屑组分以石英为主,其次是长石及各种岩屑;REE配分模式与大陆上地壳稀土元素配分模式基本一致,轻稀土元素富集,Eu负异常较为明显。其源区的构造环境是从海相过渡到陆相,最后演化成复杂的源区。川西拗陷中段蓬莱镇组有龙门山、大巴山-米仓山多个物源区,北部的主要物源区为大巴山-米仓山,南部的物源区为龙门山,中部则为混源区。     

川西地区中侏罗统沙溪庙组砂岩地球化学特征及构造意义

沉积盆地中砂岩的地球化学成分主要受物源区控制,因此通过对砂岩化学成分的分析可以揭示盆地沉积物的源区构造背景及物源属性。为了深入探讨川西坳陷中侏罗统沙溪庙组的物源及其源区属性,对研究区的稀土元素、微量元素地球化学特征进行系统的分析。应用稀土元素La/Yb-∑REE、微量元素La/Th-Hf和La/Sc-Co/Th源岩属性判断图解以及微量元素构造背景判别图解,对研究区物源及其源区属性进行了深入的讨论。结果表明:根据研究区上、下沙溪庙组地球化学特征,认为上、下沙溪庙组具有相同的物源;通过对稀土元素及微量元素特征值及比值的分析,认为该地区属于构造背景主要为大陆岛弧向活动大陆边缘转换的构造背景;沉积物物源的原始物质应主要来自上地壳,部分来自混合长英质/基性源;结合研究区周缘山系的属性分析,认为研究区在中侏罗世沙溪庙期同时受到了米仓山-大巴山及龙门山的物源的影响。     

38年生马尾松种源生长及材性联合分析

【目的】通过分析已达成熟期的马尾松种源生长与材性变异,揭示不同性状在地理种源上的变异规律,并筛选适合在安徽省六安市及类似立地区域推广的速生且材质优良的纸浆材种源。【方法】以安徽省六安市裕安区国有林木良种场的38年生(成熟林)马尾松55个种源为试材,测定其胸径、树高、管胞长度及宽度、基本密度和微纤丝角,进行生长与材性联合分析。【结果】胸径、树高、材积、管胞长度、管胞宽度、微纤丝角和基本密度在种源水平上均差异极显著(P<0.01)。各性状表型变异系数、遗传变异系数分别为3.02%~58.61%、5.56%~28.16%;胸径、树高、材积、管胞长度、管胞宽度、基本密度和微纤丝角种源遗传力分别为0.665 7、0.558 9、0.616 9、0.996 3、0.965 6、0.739 3和0.823 3。相关性研究表明:生长性状与纬度呈显著负相关,与经度相关不显著;材性与经纬度均相关不显著,但表现出局部的变异规律;生长性状间相关性高于生长与材性间相关性;微纤丝角从髓心至树皮总体随着龄级的增大而减小,木材基本密度、管胞长和宽从髓心至树皮总体随着龄级的逐渐增大而增大,变化幅度随着龄级的增大而减小。通过综合指数选择出5个综合性状优良种源,其胸径、树高、材积、管胞长度与宽度、基本密度和微纤丝角平均遗传增益分别为3.69%、5.72%、15.12%、7.05%、-1.12%、0.17%和-6.46%。【结论】成熟林马尾松种源间差异显著,并且生长性状存在从南向北逐渐减小的变异规律,材性与经纬度不相关,对其进行纸浆材生长与材性联合选择具一定潜力,可为纸浆材马尾松良种选择提供可靠依据。     

阿尔金斜坡东段古近纪路乐河组物源体系分析

通过岩芯观察、砂岩骨架组分、重矿物类型与组合特征、ZTR指数变化趋势等方法,对阿尔金斜坡古近纪路乐河组物源体系进行系统研究并恢复了母岩区性质.结果表明:路乐河组沉积时,阿尔金斜坡东段发育3大物源体系,自西向东依次为①月牙山物源,母岩主要为中性岩浆岩和变质岩,其次为酸性岩浆岩；②红三旱一号物源,母岩主要为中性岩浆岩,其次为酸性岩浆岩和变质岩；③鄂博梁物源,母岩主要为中性岩浆岩和酸性岩浆岩,其次为变质岩.其中红三旱一号物源分为两支,一支经红三旱一号Ⅰ高点主体向西南方向流入尖顶山地区,另一支经牛鼻子梁西口主体向东南方向流入碱山以北地区.     

Clay mineral composition and their sources for the fluvial sediments of Taiwanese rivers

Located at the collision boundary between the Philippine Sea Plate and the Eurasian Continental Plate,the island of Taiwan is generally recognized as an important example in the MARGINS Program Science Plan and "source-to-sink" research because of its high tectonic activity,heavy rainfall and unique geography.Large suspended sediment loads are transported to the adjacent ocean by Taiwanese rivers every year,making Taiwan an important source of sediments into the adjacent seas and a natural laboratory for studying the systemic movement of fluvial sediments from source to sink.A detailed study on the clay mineral composition of surface sediments collected from the drainage basins of 12 Taiwanese rivers using X-ray diffraction methods was conducted.Our results indicated that the clay mineral assemblages consisted dominantly of illite(approximately 73%) and chlorite(approximately 24%),with lesser abundances of kaolinite(approximately 3%) and even lower levels of smectite from the Danshuei River sediments in northwestern Taiwan.The Jhuoshuei River sediments from western Taiwan contained clay mineral assemblages that consisted of illite(approximately 75%) and chlorite(approximately 25%),but they lacked kaolinite and smectite.In southwestern Taiwan,the clay mineral assemblages were dominated by illite(approximately 75%) and chlorite(approximately 23%),but had a low abundance of kaolinite(generally < 2%) and no smectite.The clay mineral assemblages in eastern Taiwan are obviously different from those in western parts of the island.The most noticeable difference is that the average abundance of chlorite in the Hualien River from eastern Taiwan was the highest(approximately 48%) of all the Taiwanese rivers.We concluded that,in general,the clay mineral assemblages in Taiwanese rivers were mainly composed of illite and chlorite with kaolinite and smectite being scarce,and these trends are different from those in China’s mainland rivers.The clay mineral composition shown in this study was primarily determined by the properties of the bedrock,and the differential weathering intensities of the drainage area.The surface sediments in Taiwan’s rivers showed a greater abundance of illite and chlorite because the outcropped rocks were mainly composed of Tertiary sedimentary rocks,especially sandstone,shale and slate,and show strong physical weathering.The relatively high relief and more abundant rainfall also caused the clay minerals in the fluvial sediments to be transported to the estuaries down rivers from the mountains and then delivered to the adjacent seas by currents and waves over a shorter time scale.     

高邮凹陷古近系戴南组戴一段物源分析

在分析了高邮凹陷戴南组沉积期构造和沉积背景的基础上,利用重矿物组合分析法、矿物成分分析法、砂岩质量百分含量法、地震反射波组形态分析法和古地貌分析法,对戴南组戴一段的物源进行了分析.认为高邮凹陷中东部戴南组戴一段北部物源来自于柘垛低凸起,存在4个主要物源,南部物源主要来自通扬隆起区以及东南部的吴堡低凸起,存在5个主要物源.在此基础上,编制了戴南组戴一段的沉积体系分布图.     

不同种源青钱柳苗期光合特征及变异分析

用Li Cor-6400型光合仪对青钱柳12个种源进行光合指标测定。结果发现:净光合速率(Pn)及蒸腾速率(Tr)日变化表现出双峰("M"形)现象,其两次峰值分别出现在10:00及14:00;胞间CO2浓度(Ci)则呈现相反趋势,大致呈"W"形,峰值出现时间与Pn、Tr一致;气孔导度(Gs)在6:00时有最大值,随后下降,8:00之后表现出与净光合速率变化一致趋势;瞬时水分利用率(WUE)在8:00之前及12:00之后呈上升趋势,8:00—12:00之间WUE呈下降趋势。通过对种源间光合指标差异进行分析,不同种源青钱柳光合指标差异达显著水平。用差异显著的光合相关指标对各种源进行模糊数学隶属值比较,昆明、安吉、庐山、资源及舒城种源相关指标的隶属值位居前五,可初步认定江苏栽种区为光合、水分利用效率较高种源。