火山岩

Four facts about this belt are analyzed in this work:(1) typical mantle metasomatism existing in the volcanic rocks and in their inclusions,(2) the distribution range of the Krich volcanic belt estimated according to the K2O/Na2O ratio of the volcanic rocks,(3) the "cold spring and taele phenomenon" caused by adiabatic expansion of the mantle gases, and (4) the current situation of seismic activities.

文中重点论述了以下4点内容：(1)火山岩及其包体中存在典型的地幔交代作用；(2)根据火山岩K2O/Na2O比值勾画出富钾火山岩带范围；(3)地幔气体的绝热膨胀导致"冷泉和冻土现象"；(4)地震活动的现状。

This paper studied the lithologic characteristics, porosity and its evaluation, forming mechanisms of six kinds of volcanic rocks, and analyzed the evaluation history and the key factors about the main volcanic reservoirs, including andesite, basalt and tuff, etc.

对研究区火山岩岩性特征、储集空间类型、孔隙演化特征及其主要影响因素进行了深入分析，研究了区内6种火山岩的岩性特征及4个亚类储集空间的发育特征，深入分析了区内主要的火山岩储层如安山岩、玄武岩、火山角砾岩和凝灰岩等的孔隙演化过程及其控制因素。

The evolution history of the volcanic rocks goes through five stages, the forming stage, the weathering and leaching stage, the burial and tectonic\|reforming stage, the erosion stage and the oil and gas accumulation stage. Finally, the model of porosity evolution was set up with andesite and basalt as examples.

在上述研究的基础上，将火山岩储集空间的演化过程分为火山岩的形成阶段、风化剥蚀淋滤阶段、埋藏和构造作用阶段、溶蚀改造作用阶段和油气聚集成藏阶段5个阶段，并以安山岩和玄武岩为例，建立了火山岩储层的孔隙演化模式。

Volcanic gas reservoirs of low permeability in the carboniferous of a basin are characterized by deep burial depth, complex genesis, many types, wide distribution and non-evident expressions in three-porosity log curves, as well as the variedvalues of density and compression wave of main four volcanic gas reservoirs (such as the basalt, andesite, dacite and rhyolite). So a number of effective methods based on three porosity log data cannot work in identifying the volcanic gas reservoirs of the carboniferous of the basin.

石炭系火山岩的低渗透气藏具有的埋藏深、成因复杂、类型多、分布广、三孔隙度曲线响应特征不明显等特点，并且主要的四种火山岩气藏：玄武岩、安山岩、英安岩、流纹岩的密度和纵波时差测井值差别较大，因此使基于三孔隙度测井资料的一系列识别气层的有效方法在该盆地石炭系火山岩气层的识别中无明显效果。

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。

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。

This dissertation was focused on the research about the formation and evolution of NQB from the Late Triassic to the early middle Epoch of Jurassic Period, including integrated analyzing the characteristic of the key stratigraphic surfaces, the time of the key stratigraphy, regional rock straigraphy, biostratigraphy and chronostratigraphy, sedimentary system and depositional facies. On basis of these analysis, a tectonic evolution model have been established for NQB during from the Late Triassic to the early middle Epoch of Jurassic Period.1. After the systematic surface analysis about main stratigraphy units, we found that:(1) the bottom of Xiaochaka formation was comformity with the middle Triassic in the basin, and in the north margin it was deposited and overlapped on the different period stratigraphy before Triassic.(2) The top surface of Xiaochaka formation developed regionally karst and paleo-karst breccia, and was uncomformity with Nadigangri Formation, these things suggest that NQB in Xiaochaka depositing stage was developed from middle Triassic basin, and then an extensive regression occurred, the deposition was over and erosion come into being.(3) The lithologic assemblage, geochemistry, mixed fossils, and stratigraphy overlapping characteristic of Quemocuo Formation in early middle Jurassic indicted that the uncomformity surface was an extension-unconformity.2. Integrated analysis about stratigraphy division and correlation indicted that:(1) the paleontologic assemblage of Xiaochaka formation show its time was Carian -Norian stage of late Triassic. According to it was overlapped by late Triassic Nadigangri Formation, so Xiaochaka formation should be Carian - early Norian stage.(2) the SHRIMP Zircon U-Pb age of Nadigangri formation volcanic rocks wear vary form 216 to 205 Ma, so its time should be Norian, but maybe extended into Rhaetian Stage.(3) The age of its bottom volcanic rocks, the fossil assemblages of its middle and upper members and overlapped by lower Jurassic, indicted the age of Riganpeicuo Formation was Norian - Rhaetian stage. And the same time, the volcanic rocks geochemistry of Nadigangri and Riganpeicuo formation both reflected that they wear formed in rift tectonic settings. The lower lithologic and surface characteristic, fossil assemblages and its upper maybe was conformity with lower Jurassic, all reflected that the age of Tumengela Formation in Tumen area should be Norian - Rhaetian stage.

论文对晚三叠世—中侏罗世早期盆地的形成与演化开展了研究，包括关键地层界面特征分析、关键地层时代归属分析、区域岩石地层、生物地层和年代地层的综合对比分析、区域沉积体系与沉积相分析、岩相古地理分析，最终建立晚三叠世—中侏罗世早期羌塘盆沉积—构造动力演化模式。1、系统的对各地层单元的界面分析发现：(1)肖茶卡组底界在盆地内部与中三叠统整合关系，在盆地北缘为沉积超覆于不同时代的前三叠系之上：(2)肖茶卡组顶界面发育古岩溶角砾岩，与上覆那底岗日组为岩溶不整合接触，说明肖茶卡组沉积时期的羌塘盆地是在早中三叠世的盆地基础发展起来的，后期出现了广泛的海退事件，使盆地结束沉积并遭受风化剥蚀作用；(3)中侏罗统雀莫错组的岩性组合特征、岩石化学特征、古生物化石混积和地层的沉积超覆现象均表现出裂陷环境下形成的伸展不整合面的特征。2、综合地层划分与对比分析认为：(1)肖茶卡组古生物化石组合反映其时代为晚三叠世卡尼期—若利期，根据其上被上三叠统那底岗日组不整合覆盖，将其时代厘定为卡尼期—若利期早期；(2)那底岗日组火山岩SHRIMP锆石U-Pb年龄在216～205 Ma之间，其时代主要为若利期，可能包含有瑞替期：(3)日干配错组底部火山岩的年龄、中上部化石组合及其被下侏罗统整合覆盖，综合反映的时代为晚三叠世若利期—瑞替期，而且那底岗日组火山岩和日干配错组火山岩的地球化学成分分析反映两者均为引张构造背景下的产物；土门地区的土门各拉组的下部岩性及界面特征、化石组合和上部可能被下侏罗统整合覆盖，综合反映其时代为若利期—若利期。

With high silica（SiO2 = 75.49 % on average）, rich potassium（K2O = 3.88 % on average）, low titanium （TiO2= 0.136% on average）and A/CNK high than 1.1（1.53 on average）, the acidic volcanic rocks of Manghuai Formation belong to potassium-rich calc-alkali rhyolitic volcanic rock series.

官房地区火山岩属三江构造带南澜沧江构造岩浆带北段，中晚三叠世喷发了一套由中三叠统忙怀组酸性火山岩和上三叠统小定西组基性火山岩组成的火山岩系。

Geological and geochemical characteristics of the Early Ordovician volcanic rocks from North Qilian Mountain show that they are of the basalt-andesite association with no acid rocks or volcanic rocks of the shoshonite series.

早奥陶世阴沟群火山岩的地质－地球化学特征的研究结果表明，该期火山岩的岩石组合为玄武岩－安山岩组合，缺乏酸性火山岩和橄榄玄粗岩系列火山岩。

Through the study above, it formates a set of theory and method on the favourable reservoir characteristics and distribution modle of volcanic reservoir.The method can not only be applied into the volcanic rock reservoir studies of the Nanpu Sag Lower Tertiary, but also can private a good reference value to reserch on the other volcanic rocks which have the similar geological conditions.

通过以上的研究，形成了一套对火山岩储层特征及有利火山岩储层分布模式研究的理论与方法，这种方法不仅适合南凹陷下第三系火山岩储层的研究，而且对其它地质条件相似区域的火山岩特征研究也有很好的参考价值。

The split between the two groups can hardly be papered over.

这两个团体间的分歧难以掩饰。

This approach not only encourages a greater number of responses, but minimizes the likelihood of stale groupthink.

这种做法不仅鼓励了更多的反应，而且减少跟风的可能性。