Geochronology and geological significance of the strata of the Neoproterozoic Nanhua System,SW North China Craton

A set of low-grade clastic metamorphic and carbonate rocks,and greenschists outcropping in the southwestern(SW)margin of the North China Craton(NCC),was originally classified as the Paleoproterozoic Xiong’er Group according to stratigraphic correlation.To verify the age,this paper carried out detrital zircon U–Pb LA-ICP-MS dating of low-grade clastic metamorphic rocks exposed in the Changqing area at the SW margin of the Ordos Block in the SW part of the NCC.Results from detrital zircon dating indicate that the metamorphic and carbonate rocks can be classified into the Neoproterozoic Nanhua System,which is the only Nanhua System stratum in this block so far,and it probably could provide new clues to Rodinia break-up and Snowball Earth of the NCC.The nine peak ages of the low-grade clastic metamorphic rocks reflected its relatively complex provenance,and almost all major geological events experienced by the NCC basement since the Neoarchean,but some age peaks were difficult to correspond to that of the NCC,indicating that the southwestern part of the Ordos Block was also affected by the Qinling and Qiliang orogenic belts during Nanhua System of Neoproterozoic.Combined with provenance analysis,it was revealed that the current southwest boundary of the Ordos Block was the previous southwest boundary of the Ordos Block during the Qingbaikou-Nanhua Period of the Neoproterozoic.

Distribution Features of the Nanhua-Sinian Rifts and their Significance to Hydrocarbon Accumulation in the Tarim Basin

On the basis of reprocessing 34 new two-dimensional spliced long sections(20,191 km) in the Tarim Basin, the deep structure features of the Tarim Basin were analyzed through interpreting 30,451 km of two-dimensional seismic data and compiling basic maps. Seismic interpretation and geological analysis conclude that the Nanhua-Sinian strata are a set of rift-depression depositional systems according to their tectonic and depositional features. The rift valley formed in the Nanhua Period, and the transformation became weaker during the late Sinian Period, which eventually turned into depression. From bottom to top, the deposited strata include mafic igneous, tillite, mudstone, and dolomite. Three major depocenters developed inside this basin during the rift stage and are distributed in the eastern Tarim Basin, the Awati area, and the southwestern Tarim Basin. Among them, the rift in the eastern Tarim Basin strikes in the near east-west direction on the plane and coincides with the aeromagnetic anomaly belt. This represents a strong magnetic zone formed by upwelling basic volcanic rock along high, steep normal faults of the Nanhua Period. Controlled by the tectonic background, two types of sedimentary systems were developed in the rift stage and depression stage, showing two types of sequence features in the Sinian depositional stage. The Nanhua System appears as a wedge-shaped formation, with its bottom in unconformable contact with the base. The rifting event has a strong influence on the current tectonic units in the Tarim Basin, and affects the distribution of source rock in the Yuertus Formation and reservoir beds in the Xiaoerbulake Formation in Lower Cambrian, as well as the gypseous cap rock in Middle Cambrian. The distribution features of the rifts have important and realistic significance for determining the direction of oil and gas exploration in the deep strata of the Tarim Basin. Comprehensive analysis suggests that the Tazhong region is the most favorable zone, and the Kalpin-Bachu region is the optimal potential zone for exploring sub-salt oil and gas in deep Cambrian strata.

Layout Optimization of Riverside Residential Area Based on Thermal Comfort: A Case Study of Nanhua Village, Shenzhen

Based on the previous researches on building layout with thermal comfort, this paper Stud Shenzhen Nanhua Village to explore the way of using building layout to change thermal environment of riverfront residential areas. The results showed that a more comfortable outdoor thermal environment could be obtained by applying proper building layouts favorable for the thermal comfort of the Nanhua Village. It proves again that efficient and feasible building layout, which is suitable for a river microclimate, is important in improving thermal comfort of a riverside residential area. The study also provides a good example for the future architectural designs of a riverside residential area for obtaining thermal comfort.

Late Quaternary Activity of the Chuxiong-Nanhua Fault and the 1680 Chuxiong Ms6 3/4 Earthquake

In this paper,according to the results of the satellite imagery interpretation and field investigation,we study the active features and the latest active times of the ChuxiongNanhua fault,the Quaternary basins formation mechanism,and the relationship between the fault and the 1680 Chuxiong M_S6 3/4earthquake. Several Quaternary profiles at Lvhe,Nanhua reveal that the fault has offset the late Pleistocene deposits of the T2 and T3 terraces of Longchuan river, indicating that the fault was obviously active in late Quaternary. The Chuxiong-Nanhua fault has been dominated by dextral strike slip motion in the late Quaternary,with an average rate of 1. 6-2. 0 mm/a. Several pull apart Quaternary basins of Chuxiong,Nanhua,and Ziwu etc. have developed along the fault.The 1680 Chuxiong M_S6 3/4earthquake and several moderate earthquakes have occurred near the fault. The Chuxiong-Nanhua fault are the seismogenic structure of those earthquakes,the latest fault movement was in the late-Pleistocene,and even the Holocene.In large area,the Chuxiong-Nanhua fault and the eastern Qujiang fault and the Shiping fault composed a set of NW-trending oblique orientation active faults,and the motion characteristics are all mainly dextral strike slip. The motion characteristics,like the red river fault of the Sichuan-Yunnan Rhombic Block southwestern boundary,are concerned with the escaping movement of the Sichuan-Yunnan Rhombic Block.

New U-Pb age constraints on the upper Banxi Group and synchrony of the Sturtian glaciation in South China

The Nanhua basin in South China hosts well-preserved middle-late Neoproterozoic sedimentary and volcanic rocks that are critical for studying the basin evolution, the breakup of the supercontinent Rodinia, the nature and dynamics of the "snowball" Earth and diversification of metazoans. Establishing a stratigraphic framework is crucial for better understanding the interactions between tectonic, paleoclimatic and biotic events recorded in the Nanhua basin, but existing stratigraphic correlations remain debated, particularly for pre-Ediacaran strata. Here we report new Laser Ablation Inductively Coupled Plasma Mass Spectrometry(LA-ICPMS) U-Pb zircon ages from the middle and topmost Wuqiangxi Formation(the upper stratigraphic unit of the Banxi Group) in Siduping, Hunan Province, South China. Two samples show similar age distribution, with two major peaks at ca. 820 Ma and 780 Ma and one minor peak at ca. 910 Ma, suggesting that the Wuqiangxi sandstone was mainly sourced from Neoproterozoic rocks. Two major age peaks correspond to two phases of magmatic events associated with the rifting of the Nanhua basin, and the minor peak at ca. 910 Ma may correspond to the Shuangxiwu volcanic arc magmatism, which represents pre-collision/amalgamation subduction on the southeastern margin of the Yangtze Block. The youngest zircon group from the topmost Wuqiangxi Formation has a weighted mean age of 714.6±5.2 Ma, which is likely close to the depositional age of the uppermost Banxi Group. This age, along with the ages reported from other sections, constrains that the Banxi Group was deposited between ca. 820 Ma and ca. 715 Ma. The age of 714.6±5.2 Ma from the top of the Wuqiangxi Formation is indistinguishable with the SIMS U-Pb age of 715.9± 2.8 Ma from the upper Gongdong Formation in the Sibao village section of northern Guangxi, South China. It is also, within uncertainties, overlapped with two TIMS U-Pb ages from pre-Sturtian strata in Oman and Canada. These ages indicate that the Jiangkou(Sturtian) glaciation in South China started at ca. 715 Ma instead of ca. 780 Ma and support a globally synchronous initiation of the Sturtian glaciation at ca. 715 Ma.

Geochronological and Geochemical Evidence for the Sedimentary Transformation from the Banxi Period to Nanhua Glacial Period

Objective There has been considerable debate about the definition of the lower boundary of Nanhua System by far.One definition is based on sedimentary sequence of different stages of basin evolution,focusing on whether deposits of the Banxi Period should be classified as Nanhua System.Another is the onset time of Nanhua glacial period.

Occurrence, Damage and Control Strategies of Major Pests, Diseases and Weeds in Sugarcane Areas of Lincang Nanhua Sugar Industry Co., Ltd.

The pests, diseases and weeds in sugarcane areas of Lincang Nanhua Sugar Industry Co.,Ltd. were investigated at seedling stage, growth stage and maturity stage of sugarcane from 2012 to 2016. The occurrence and damage of diseases, pests and weeds were analyzed, and the problems in prevention and control were discussed based on the local conditions of sugarcane production. The species, occurrence and damage characteristics of diseases, pests and weeds were ascertained, and the corresponding strategies and technical measures were proposed.

Rectifying the Neoproterozoic Stratigraphic Framework of Eastern Jiangnan Orogen, Southeast China

Studies on the metamorphic and related magmatic rocks within the Jiangnan Orogen,southern China,are important to understand the formation and evolution of this Neoproterozoic orogen because they can provide evidence for revealing the tectonic evolution of the South China Block.Following on from earlier attempts at stratigraphic correlation and creating a framework for the low-grade metamorphosed basement,new first-hand information on the composition and deformation of the East Jiangnan Orogen basement indicates that the sedimentary rocks in the north are composed of the sequential Shangxi Group(Gp)and the overlying Likou Gp,with a clear regional unconformity in between.The Likou Gp includes the Zhentou Formation(Fm.)and the Dengjia Fm.,with the previously named Puling Fm.only basalt interbeds within the Dengjia Fm.The Xucun granodiorite pluton of^830 Ma intrudes the Shangxi Gp,thereby resulting in a 100 mwide hornfels zone within the wall rocks,indicating that the formation of the group occurred earlier than that of the pluton.By contrast,the southern metamorphic rocks of the Xikou Gp and the overlying Jingtan Fm.are flaky,disordered,and strongly deformed.The Jingtan Fm.is roughly equivalent to the Heshangzhen Gp and includes the Zhoujiacun conglomerates in the lower part and a rhyolite in the upper part with interbedded basalt.This assessment of Neoproterozoic stratigraphic sequences and magmatic rocks in the east of the Jiangnan Orogen differs from and rectifies previous studies,emphasizing that explanation of analytical results,particularly geochronology,should be consistent with facts gathered in the field.

连续电磁剖面法在塔里木盆地麦盖提斜坡裂陷槽深部构造研究中的应用

随着对塔里木盆地深层油气勘探认识不断深入,认为震旦—南华系裂陷槽对烃源岩的发育保存有着重要的控制作用,因此对该区域的裂陷槽探测是油气勘探的重要探索方向。前人研究认为对塔西南地区麦盖提斜坡处存在震旦—南华系裂陷槽,但受限于该区域地震资料品质,对该区域深层结构尤其是对基底和裂陷槽分布形态和范围认知不清。因此,通过一条跨过麦盖提斜坡与叶城凹陷的连续电磁剖面法剖面,结合研究区地质情况与井资料,构建了区域电阻率的物性分层结构,完成了对实际数据的二维反演,获取了该区域的深部电性结构与CEMP剖面的综合地质解释结果。为该区域新元古代裂陷槽发育情况的判断提供了新的电磁证据,也进一步刻画了基底、裂陷槽的电性特征与结构。探测结果认为裂陷主要由正断层控制,呈现裂陷群特点,裂陷多呈半地堑、不对称地堑及堑—垒相间的构造样式,在麦盖提斜坡、叶城凹陷处中部、南部的区域发育两个裂陷群,有利于区域内的烃源岩沉积,其中裂陷内震旦—南华系地层沉积较厚的区域具有较好的深层油气勘探潜力。

类型学视域下滇中彝语倮倮话连动结构研究

连动结构是现代汉语中一种特殊构词方式,在汉藏语系的语法研究中具有重要意义。其主要由两个或两个以上的动词要素构成,与其他构词法有较明显的区别,连动结构可采用“V1+之后再V2”格式进行辨别。从滇中南华彝语倮倮话连动结构的形式类型、语义结构类型以及论元特点三个角度进行分析,发现其具有三个主要特点:一是滇中彝语倮倮话的连动结构具有动词间有成分插入时具有多元性,二是其语义类型可分为时序关系和事理逻辑关系两大类,三是多个动词可分主宾语论元共享和不共享的特点。

滇中南华彝语卢辘话存在动词语义指向研究

“存在”是一切事物的运动方式和表现形式,任何事物都存在于某一个时空中,存在句作为表现事物存在的语言形式,在不同的民族语中用法各异。滇中南华五街镇华双村彝语卢辘话存在动词可分为肯定存在动词和否定存在动词两种,其中肯定存在动词可分典型存在动词“有”(dʐa33)“在”(dʐa33 la55)和非典型存在动词“处置类”“运动类”“生产类”等六类;否定存在动词则用“ŋ21”来构成。在对存在动词分类的基础上,进一步分析存在动词的用法和所构成的存在句。

扬子地块北缘镇巴穿心店地区南华系碎屑锆石U-Pb年龄及其物源示踪

扬子地块北缘镇巴穿心店地区发育有完整的南华系—震旦系沉积地层,记录了研究区及邻区南华纪沉积特征,对于研究扬子地块北缘新元古代晚期构造演化历史和Rodinia超大陆演化过程具有重要的地质意义。研究区南华系由下至上可划分为4套岩石地层单位,分别为长安组、古城组、大塘坡组和南沱组。南华系砂岩地球化学特征表明,研究区南华系化学风化作用较弱,经历了较低程度的沉积物再旋回作用。砂岩的CIA、CIW、PIA、Rb/Sr等古气候指标显示,研究区南华系具有由寒冷干燥—有波动的寒冷干燥—趋于稳定的温暖湿润—寒冷干燥的古气候演化趋势。在Dickinson三角图解中清晰地反映了南华系各组砂岩具有再旋回造山带和切割岩浆弧物源的特征,同时砂岩岩石地球化学特征也指示南华系的物源区主体应由中酸性岩浆岩组成。南华系长安组、古城组和南沱组3件碎屑锆石U-Pb年龄样品的年龄分布特征类似,主要年龄区间为新元古代晚期(约780~约641 Ma),并显示出约750~约740 Ma的显著峰值。结合区域地质资料,研究区南华系沉积时代应为约720~约635 Ma,物源应主要来自位于现今研究区西侧的扬子地块北缘汉南—米仓山微地块的新元古代岩浆岩,其沉积事件对应于新元古代中晚期扬子地块北缘伸展-裂解阶段,为Rodinia超大陆裂解过程的沉积响应。

陕南镇巴小洋坝地区南华系物源分析:来自碎屑锆石U-Pb年龄、碎屑成分分析及地球化学的证据

扬子板块北缘镇巴小洋坝地区出露了一套完整的南华纪沉积地层,分析其沉积时限、沉积环境及物源示踪对扬子板块北缘新元古代中晚期沉积-构造演化具有重要意义。本文对陕南镇巴小洋坝地区南华系砂岩样品进行碎屑锆石U-Pb测年分析,化学蚀变指数(CIA)、化学风化指数(CIW)、斜长石蚀变指数(PIA)、成分变异指数(ICV)判别及物源分析。结果显示小洋坝地区南华系的沉积时限应为720~635 Ma。长安组、古城组、南沱组沉积于寒冷干燥气候,而大塘坡组沉积于温暖湿润气候。其物源区主要为扬子板块北缘汉南—米仓山微地块。研究区南华系对应了新元古代中晚期扬子板块北缘地区的后碰撞-裂解阶段,是新元古代中晚期Rodinia超大陆裂解在该地区的沉积响应。

黔东北松桃高地南华系铁丝坳组和两界河组碎屑组分及源区背景

雪峰运动的构造属性一直存在较大争议。统计黔东北松桃高地南华系铁丝坳组和两界河组的陆源碎屑组分,并应用Dickinson三角图解原理进行分析。研究结果显示:铁丝坳组和两界河组沉积时期陆源碎屑的物源主要来自火山弧源区和再旋回造山带,伴随有火山活动;铁丝坳组的碎屑成分成熟度较低,主要投点在火山弧物源区,显示了近源剥蚀、搬运堆积的特征,两界河组的石英矿物屑含量比铁丝坳组高,趋向于再旋回造山带物源;碎屑组分中岩屑的岩性组合为玄武岩、安山质玄武岩、粗面岩、凝灰岩、熔结凝灰岩、流纹岩、长英质糜棱岩等,表明在铁丝坳组和两界河组沉积时期或沉积之前,研究区就已进入陆内裂陷和板内造山的大地构造背景。研究可为该地区雪峰运动的构造属性提供微观证据。

粤北地区“南华系”沉积时代的重新厘定:来自碎屑锆石年代学的证据

粤北地区横跨湘桂赣和武夷两个地层分区,大地构造上位于华夏地块西部,介于武夷、云开两个微陆块之间。粤北南华纪地层是研究华夏地块新元古代晚期构造演化等问题的重要载体,但该地区南华系的确定和划分较大程度上依赖与周边省份相应岩石地层的岩性组合和层序的对比,而周边省份的相应岩石地层单位的认识近年来发生较大的变化,因此,粤北地区“南华系”的重新厘定显得极为必要。本文对粤北地区原定为“南华系”大绀山组和活道组开展碎屑锆石U-Pb年代学研究,获得最年轻一组锆石加权平均年龄分别为422±4 Ma和430±4 Ma。结合岩性组合、区域地质调查研究成果及文献数据,暂将该地区原定的南华系厘定为下泥盆统。碎屑锆石年龄谱显示,其与周边地区泥盆系均具有450~420 Ma、1000~900 Ma以及~2450 Ma为主的锆石年龄显示,且在800~550 Ma之间形成复杂的次级峰值,可能指示了相似的物源。综上,建议在开展华夏地块新元古代构造演化等研究中,需首先对南武夷-云开地区南华系的沉积层位做细致的认定。

黔东、湘西及桂北南华纪盆地充填序列与岩相古地理特征

黔东、湘西及桂北发育一套超覆在雪峰运动界面上的南华纪寒冷气候沉积的楔状地层,该楔状地层沿湘黔桂裂谷盆地分布,跨越了上扬子陆块东南缘及江南造山带西南段。通过对区内不同位置典型岩相地层剖面对比研究,开展沉积相与沉积微相研究,推断古海岸线变化的范围及分布特征、古流向及古地理概貌,重塑了不同阶段盆地演化的岩相古地理面貌及沉积模式。岩相古地理特征显示,研究区南华纪为裂谷盖沉积期,其盆地充填演化划分为3个阶段,即隆升剥蚀及早期冰碛岩堆积阶段、间冰期充填阶段和晚期冰碛岩堆积阶段。南华冰期(长安、南沱冰期)为冰内、冰前、冰外冰水重力流沉积;富禄间冰期以河流、潟湖、三角洲沉积为主,发育含锰碎屑岩沉积。该成果为湘黔桂裂谷盆地充填演化、岩相古地理特征及成矿资源效应研究提供了新的基础资料,对地层、寻找矿源、研究其形成的构造地质背景具有一定的指导意义。

滇东北会泽地区南华系沉积相与古气候特征——来自元素地球化学的证据

通过资料收集、剖面测制、岩矿鉴定、主微量元素分析、特征指数参数对比、沉积相综合建模等一系列工作,对滇东北会泽地区南华系沉积环境和古气候进行了探讨.该区南华系自下而上出露澄江组和南沱组,二者均为陆源碎屑岩系,呈平行不整合接触.澄江组主要包括粉砂质泥岩、粉砂岩、细砂岩、细粒石英杂砂岩和岩屑砂岩等.南沱组主要为一套灰黄色中层状复成分冰碛砾岩.澄江组中沉积旋回发育,可见小型槽状交错层理、斜层理、平行层理、水平层理等沉积构造.对澄江组细碎屑岩样品的主微量元素特征指数SD、CV、CIA、CIW、PIA、ICV、Na/K、Al/Ca、Ru/Sr、V/Cr、U/Th、Ni/Co等进行分析,其结果均指示氧化、弱氧化的沉积环境.研究认为澄江组为湖泊相,包括滨湖亚相和浅湖亚相,为温暖湿润气候类型;南沱组为冰川相,包括冰碛亚相和冰湖亚相,为寒冷干燥气候类型.

模糊综合评价法在南华土壤肥力评价中的应用

为掌握南华县土壤养分指标和综合肥力状况,系统采集表、深层土壤样品,选取硼(B)、有机质(SOM)、铜(Cu)、钾(K_(2)O)、锰(Mn)、钼(Mo)、氮(N)、磷(P)、铁(TFe_(2)O_(3))、锌(Zn)和酸碱度(pH)11种土壤养分指标,结合地质背景,对区内主要土壤养分指标的地球化学特征进行研究。通过隶属度函数模型和因子分析,利用模糊评价法对土壤综合肥力进行评价。结果表明:受地质背景影响,区内表层土壤pH平均值为5.33,普遍呈酸性。氮养分和铜、锌等微量元素指标较丰富,磷、钾和有机质等指标相对缺乏,土壤综合肥力状况总体较好,大多数达到肥沃和较肥沃水平。与第二次全国土壤普查结果相比,区内表层土壤pH平均值降低,呈明显酸化,有机质和氮含量总体保持平稳。

由“全生”至“全于道”:王雱对《庄子》内七篇的解读

王雱《南华真经新传》探绎了《庄子》各篇上下之间的逻辑次序及内在关联,将内七篇看作层层递进的整体,形成完整的性命系统。在内七篇中,《逍遥游》为总序,其余六篇两两成对,分别体现了个人的“全生”、经世的“全生”、由“全生”至“全于道”三个阶段的修养理路。由此反映出“有为入于无为”始终存于王雱的思想中,展现了王安石新学派哲学的理论关切和思想意蕴。

桐柏—大别造山带中部娘娘顶花岗岩成因——锆石U-Pb年龄、岩石地球化学及Sr-Nd同位素证据

娘娘顶花岗岩体位于桐柏—大别造山带中部﹐其侵位时代及形成构造环境还不清楚。采集娘娘顶花岗岩样品,开展锆石U-Pb年代学、岩石地球化学及Sr-Nd同位素研究,探讨其岩浆源区特征、岩石成因、构造环境及其与杨新岩铍矿点的关系。结果表明,娘娘顶花岗岩的锆石U-Pb年龄为(752.6±9.0)Ma,属南华纪岩浆作用产物,仅构成杨新岩铍矿点的赋矿围岩;具有高硅(SiO_(2)含量为72.56%~77.26%)、富碱(Na_(2)O+K_(2)O含量为7.37%~8.86%)、过铝质(A/CNK为0.97~1.22)等特征,Rb、K、Th等元素相对富集,Ba、Sr、Ti、P等元素明显亏损,稀土元素配分曲线呈右倾的轻稀土元素富集型,具明显负Eu异常(δEu为0.2~0.7),表明岩石为铝质A型花岗岩;(^(87)Sr/^(86)Sr)i为0.710605~0.710608,εNd(t)为-4.94~-5.05,相应的Nd模式年龄t_(DM)为1.83~1.84 Ga,具有大陆上地壳特征,可能为古—中元古代古老基底部分熔融的产物;主量元素CaO、MgO、TFeO、TiO_(2)与SiO_(2)均显示负相关关系,其岩浆演化机制应以结晶分异作用为主。综合来看,娘娘顶花岗岩形成于新元古代伸展背景。