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41.
安徽当涂新桥镇位于长江中下游冲积平原,第四纪孢粉丰富。可分成为五个孢粉带: 带一,松—冷杉—云杉—栎孢粉带,为较湿冷气候—晚更新世末期; 带二,松—栎—水龙骨科孢粉带,湿暖、湿润气候—前北方期—北方期; 带三,松—铁杉—枫香孢粉带,为热、湿气候—大西洋期; 带四,分为两个亚孢粉带:(1)松—栎—环纹藻孢粉亚带;(2)松—栎—蒿—藜孢粉亚带,为稍温湿—温干气候—亚北方期; 带五,松—栎—禾本科孢粉带,反映温暖,湿润气候—亚大西洋期。 相似文献
42.
叠层石广泛见于燕山西段前寒武系雾迷山组,文中将其分为六种类型:核形石、凝块石、层状叠层石、波状叠层石、锥状叠层石和柱状叠层石。叠层石形态的变化由前向后代表由低能向高能的环境转变,其中以层状叠层石在雾迷山组最为丰富。研究表明,在当时无捕食动物与钻孔动物存在的情况下,大多数叠层石发育于潮下带环境。层状和波状叠层石主要出现在潮下高能带的下部,少量见于受保护的潮间环境。潮下层状和波状叠层石以其色深、纹层密集、缺乏干裂收缩缝和窗格状组构区别于潮间带。锥柱状叠层石出现于潮间带和潮下高能带的上部;潮间带的锥柱状叠层石可能因暴露干裂而继承性地有壁,但潮下带的却可能没有。核形石和凝块石占据着泻湖和水下凹地(生物丘之间的低洼地或废弃潮汐沟道)等低能环境。燕山西段的叠层石罕见于潮上带和波基面之下的潮下低能带。 相似文献
43.
44.
本文以海南省416名黎族正常学龄儿童为对象,对掌轴三叉t的位置,用atd角,tpD值和t横向指数三个参数进行研究,将数据进行了统计学分析,分别求出三个参数与年龄的相关系数和回归方程,并与有关资料进行了比较。 相似文献
45.
数理统计方法在测定脉图生理年龄中的应用 总被引:1,自引:0,他引:1
本文应用数理统计方法来研究人的生理年龄与人体脉图生理参数之间的关系.通过建立回归分析模型、进行显著性检验、选择最优回归方程等过程的原理,找出并论证了人的生理年龄同血压和各种脉图之间的相互联系. 相似文献
46.
Weixuan Fang Ruizhong Hu Wenchao Su Jiafei Xiao Liang Qi Guohao Jiang 《科学通报(英文版)》2002,47(10):874-880
Emplacement ages of lamproites that comprise lamproite and olivine lamproite in Zhenyuan County, Guizhou Province, China, have been constrained by the whole-rock Sm-Nd and Rb-Sr isochron methods and the whole rock K-Ar method. Intrusive activities of lamproites in the Sinantang area of Zhenyuan County, Guizhou Province, took place during the Late Cambrian, as indicated by the Sm-Nd isochron ages ( t ) = (503 ± 17) (2σ) Ma and by the Rb-Sr isochron ages ( t ) = (501.2 ± 4.6) (2σ) Ma. Intrusive activities of olivine lamproites at the Maping with Ⅱ-type diamond and Xitou in Zhenyuan County, Guizhou Province, took place from the Late Cambrian to the Early Ordovician, as evidenced by the Sm-Nd isochron ages ( t ) = (502 ± 27) (2σ) Ma and by the Rb-Sr isochron age ( t ) = (502 ± 27) (2σ) Ma. This suggests that the upwelling hot materials derived from the deep mantle were emplaced from the Late Cambrian to the Early Ordovician (503-497 Ma), while the time terminal of cooling of the geothermal event of magmatism-tectonism probably was at 442.64-435.54 Ma, as dated by the whole rock K-Ar method. 相似文献
47.
信息时代档案管理现代化刍议 总被引:4,自引:2,他引:4
信息时代要求加快档案管理现代化建设步伐。为此,必须树立现代化管理意识,建立档案现代化技术标准,强化数据库基础建设,实现档案信息资源共享,培养现代化的档案管理人才。 相似文献
48.
The Louzidian normal fault occurs as the eastern detachment fault of the Kalaqin metamorphic core complex. Field observations
and microstructural analyses reveal that the Louzidian-Dachengzi ductile shear zone developed in its lower-plate was genetically
related to sinistral strike-slips and extensional faulting. Two samples from this ductile shear zone yield 40Ar-39Ar plateau ages of 133 Ma (Bi) and 126 Ma (Kp), which are concordant with their isochron ages. The plateau age of 133 Ma (Bi)
records the formation age of the ductile shear zone. The inconsistent relationship between the earlier strike-slip ductile
shear zone and the later normal fault makes the Kalaqin Quasi-metamorphic core complex distinctive from Cordilleran metamorphic
core complex. These ages provide important geochronological data for putting constraints on the formation age and genesis
of such ductile shear zones. 相似文献
49.
Two ductile shear zones trending EW and NNE respectively not only controlled the tectonic framework of the northern North
China, but also constrained the geodynamic background for gold mineralization in this region. Field observations and microstructural
analyses reveal that the EW trending ductile shear zones are mainly contributed to dextral compressional deformation resulting
from top-to-the-southeast oblique thrust shearing, whereas the NNE trending ones are genetically related to sinistral strike-slip
and extensional faulting. One sample from the former yielded an 40Ar–39Ar plateau age of (219± 4) Ma (Bi) and two samples from the latter gave 40Ar–39Ar plateau ages of (116± 2) Ma (Bi) and (127±3) Ma (Bi). These ages provide constraints on the top-to-the-southeast oblique
thrusting event occurring in Late Triassic and the sinistral extensional and strike-slip faulting event which occurred in
Early Cretaceous. 相似文献
50.
Two ductile shear zones trending EW and NNE respectively not only controlled the tectonic framework of the northern North China, but also constrained the geodynamic background for gold mineralization in this region. Field observations and microstructural analyses reveal that the EW trending ductile shear zones are mainly contributed to dextral compressional deformation resulting from top-to- the-southeast oblique thrust shearing, whereas the NNE trending ones are genetically related to sinistral strike-slip and extensional faulting. One sample from the former yielded an 40Ar-39Ar plateau age of (219±4) Ma (Bi) and two samples from the latter gave 40Ar-39Ar plateau ages of (116±2) Ma (Bi) and (127±3) Ma (Bi). These ages provide constraints on the top-to-the-southeast oblique thrusting event occurring in Late Triassic and the sinistral extensional and strike-slip faulting event which occurred in Early Cretaceous. 相似文献