流纹岩

Based on plentiful isotopic dating data and geological studies, the authors, in this paper, discuss the geological meanings of the two isotopic ages given by Lapierre et al., and conclude:① Mesozoic volcanic activities in Zhejiang are most frequent in 130～83 Ma, that is, from the early to late Cretaceous but not the late Jurassic;② The Jiande and Moshishan groups are nearly in the same period and not in an upper—lower stratigraphic relationship with each other;③ The period of 110～100 Ma is a transitional stage from the early high-K calc-alkaline dacite—rhyolite associated with diorite—granodiorite） to the late basalt—rhyolite（associated with K-feldspar granite—alkali granite）.

本文就Lapierre等文中124 Ma和97 Ma两个年龄的地质意义、幕次划分以及浙西与浙东火山岩时代对比作出评论，并厘定浙江中生代火山岩时代归属，提出：①浙江中生代火山活动时代为132～83 Ma；②浙西建德群与浙东磨石山群火山岩并不存在上下关系，地质接触关系、古生物组合和大量同位素定年数据都不支持Lapierre等的浙西与浙东火山活动幕次的对比方案；③ 110～100 Ma为早期高钾钙碱性英安岩—流纹岩（伴生闪长岩—花岗闪长岩）向晚期玄武岩—流纹岩（伴生钾长花岗岩—碱性花岗岩）过渡的转折期。

Early Cretaceous granitic volcanic-intrusive complex in Xiushanlinchang of northeastern Da Hinggan Mt. consists mainly of rhyolite, rhyolite ignimbrite-trachytic dacite, trachyandesite formed in eruptive cycle stage and adamellite porphyry-geode syenogranite-graphic alkali feldspar syenogranite formed in hypabyssal invasion stage.

大兴安岭东北部秀山林场一带的早白垩世花岗质火山－侵入杂岩体由喷发旋回期的流纹岩、流纹质熔结凝灰岩－粗面英安岩、粗安岩和浅成侵入期的二长花岗斑岩－晶洞正长花岗岩－文象碱长正长花岗岩构成。

Although much less common than granite, rhyolite eruptions are important because they are by far the most explosive of all volcanic phenomena.

流纹岩。虽然少得多，比常见的花岗岩，流纹岩喷发是重要的，因为它们是迄今最具爆炸性的所有火山现象。

The rhyolite of upper Luliang Group is a typical A-type volcanic rock and is a constituent member of an A-type volcanic - intruded complex in this area.

研究表明吕梁群流纹岩是一个典型的早元古代A型流纹岩，是本区A型火山一侵入杂岩的组成部分。

The study of their precise UPb geochronology and characteristics of rock associations shows that (1) small amount of EarlyTriassic (~248 Ma) volcanic rocks were preserved and cropped out in the area, which consist mainly of thin bed of andesitic rocks intercalated with minor basaltic andesites; that (2) the MiddleTriassic magmatism was characterized by extensive felsic igneous rocks with minor basalts interbedded in the middle of volcanic sections in part of areas, and the late MiddleTriassic rhyolites and main body of Lincang granitic batholith have the same extrusive/intrusive time with the age of ~230 Ma; that (3) the LateTriassic volcanic sequences are principally composed of basalts with minor interlayered rhyolites, exhibiting typical characteristics of bimodal volcanics.

三叠纪岩浆作用广泛发育于澜沧江南带，锆石UPb年代学结果及岩石组合特征显示：(1)该区残留有少量的早三叠世火山岩(约248 Ma)，主要为一套薄层的以安山岩为主的火山岩；(2)中三叠世以大规模的酸性岩浆作用为主，部分地段的中部夹有少量的玄武岩，其中晚期的流纹岩与该区出露巨大的临沧花岗岩基主体具有一致的形成时代(约230 Ma)；(3)晚三叠世则以基性火山岩为主，夹少量流纹岩为特征的&双峰式&火山岩组合。

In addition, the features of elemental geochemistry of all samples suggest that (1) the EarlyTriassic andesitic rocks, characterized by characteristic natures of island arc volcanics, likely erupted in the subduction setting; that (2) the generation of LateTriassic rhyolites with an affinity of Alike granite and synchronously main body granites in the Lincang batholith displaying similar geochemical features, is closely related with the postcollision or latecollision setting; that (3) although the LateTriassic basic rocks partly show island arc volcanics such as highAl contents and NbTa depletion, some of them possessing highMg contents and mostly having traceelement ratios similar to intraplate basalt, which indicates that they erupted in the postcollision rift environment.

元素地球化学特征表明，早三叠世火山岩具有典型的岛弧火山岩的特征，暗示其很可能形成于俯冲的构造环境；中三叠世晚期的流纹岩与临沧花岗岩基主体具有非常相似的地球化学特征，结合其流纹岩具有A型花岗岩属性，表明该区中三叠世火成岩形成于碰撞后的构造背景；而晚三叠世基性火山岩虽然在地球化学特征上显示出与岛弧火山岩相似的高铝和NbTa的亏损，但其中部分火山岩具有高镁和板内玄武岩的微量元素比值特征，说明这些火山岩可能形成于碰撞后裂谷环境。

On the basis of an integrated analysis of the geochemical features of these volcanic rock associations,this paper concludes that thebasalts originated mainly from interaction between mantle-derived magma and low-crustal materials, and rhyolitic volcanic rocks resulted from thermal and chemical interaction between basaltic magma and the upper part of crustal materials.Basalts and rhyolites in different cycles have different source regions,and they are products of multiperiodic pulsive layer partial melting.

根据对火山岩地球化学特征的综合分析表明，玄武岩主要为幔源岩浆与下部地壳岩石相互作用的产物，而流纹岩则为玄武岩浆与上部地壳物质进行热及成分交换的结果，不同旋回的玄武岩和流纹岩有不同的源区，为多次脉动分层部分熔融的产物。

Parisite is hosted in the granular rhyolite, rhyolite and rhyolitic ignimbrite. The host rocks were formed in Late Early Cretaceous Epoch buried to depth of

氟碳钙铈矿的寄主岩为球粒流纹岩、流纹岩、流纹质熔结凝灰岩、流纹质凝灰岩，其寄主岩分布深度为2930~3830m，形成时代为早白垩世晚期。

The metal elements of the volcanic-hosted massive sulfide deposit have two sources, the copper and zinc are derived from rhyolitic magmas whereas the lead are probably related to old sediments overlying the rhyolites.(4) It is suggested here that the volcanic rocks hosting massive sulfide deposit in the north Qilian orogen, which are previously considered as a bimodal suite of Neo-proterozoic to middle Cambrian age in a continental rift, are virtually related to subduction magmatism in Ordovician age, and there might have no continental rift magmatism of Neo-proterozoic to middle Cambrian in the north Qilian.

Th/Ta比高(5.0～11.7)，εNd为较大的负值(-2.6～-8.4)，流纹岩的形成可能是两个端元组分混合的过程、或是上地壳混染的结果，形成在活动陆缘环境；(3)北祁连块状硫化物矿床成矿金属物质具有两种来源，Cu、Zn等来源于流纹岩，而Pb的来源可能与古老沉积物有关；(4)本文认为，前人厘定的北祁连新元古代-中寒武纪赋存块状硫化物矿床的大陆裂谷双峰式火山岩应是与俯冲作用有关的奥陶纪火山岩，说明北祁连可能不存在新元古代-中寒武纪的大陆裂谷活动。

The activities of Wangtian′e volcano lasted for three periods:①The Changbai period volcanic rocks consisting mainly of trachybasalt with small amount of alkalic basalt and basaltic trachyandesite;② The Wangtian′e period can be further divided into early and late periods, the early period volcanic rocks consisting of basaltic trachyandesite and trachyte, the late period volcanic rocks cosisting of alkalic rhyolite;③The Hongtoushan period volcanic rocks consisting of alkalic rhyolite.

望天鹅火山活动从早到晚分为三期：①长白期以粗面玄武岩为主，少量碱性玄武岩和玄武质粗安岩；②望天鹅期又分早晚两个亚期，早期玄武质粗安岩和粗面岩，晚期碱性流纹岩；③红头山期碱性流纹岩。

Cynanchum Lingtai apricot production in the average weight 65 grams, the brightly-colored fruit, juicy rich, sweet-sour taste, sweet from the nucleolus, when the late Qing Dynasty famous Shaanxi, Gansu provinces, the Qing imperial court Tongzhi tribute for years.

灵台生产的牛心杏平均单果重65克，果实色泽鲜艳，汁多味浓，甜酸适口，离核仁甜，清末时就驰名陕、甘两省，清同治年间曾为朝廷贡品。

Chenopodium album,Solanum nigrum, and Amaranthus retroflexus were very susceptible to the herbicides. Polygonum persicaria and Abutilon theophrasti were relatively less susceptible to the herbicides, and Lycopersicon esculentum was not susceptible to it. The relationship between reduction rates of weed biomass and PPM values of weed leaves 2,4, and 6 days after treatment was established.

供试的6种杂草对该混剂的敏感性存在显著差异：红心藜Chenopodium album、龙葵Solanum nigrum和反枝苋Amaranthus retroflexus对该混剂最敏感，ED90值分别为47.65、71.67和29.17g/hm2；春蓼Polygonum persicaria和苘麻Abutilon theophrasti敏感，ED90值分别为96.91、114.20g/hm2；而番茄不敏感。