某地含钾火山岩释钾能力实验研究

某地含钾火山岩储量大，易开采，主要矿石为沸石、透长石、黑云母以及玻璃质等，平均含氧化钾３３１％．通过初步实验，速效钾含量达到了供钾潜力的中～极高水平，可直接农用，代替部分化肥，在喀斯特红土地区。

草滩沟群、丹凤岩群火山岩对比及其构造环境分析

通过北秦岭造山带西段凤县地区 1∶ 5万辛家庄、红花铺幅区调填图及前人成果 ,对位于秦岭岩群南北两侧的丹凤岩群和草滩沟群火山岩的岩石类型、岩石化学及地球化学特征进行对比 ,认为二者均属亚碱性岩系之钙性 -钙碱性系列 ;前者为中 -基性岩组合 ,显示了岛弧外侧 -边缘海型的构造背景特征 ;后者为中 -酸性岩组合 ,具弧后盆地拉张裂谷活动背景特征。为探讨北秦岭造山带的地质发展史提供了新的资料。

1：20万德化、福清幅区域重力异常的研究

本文主要依据１：２０万德化、福清幅重力场特征，结合其它区域物探及地质、区域化探、遥感资料，把本区构造单元划分为３个Ⅰ级构造单元，３个Ⅱ级构造单元；推断解释环状构造两个，断裂构造带３３条，其中深断裂带５条，大断裂带９条，一般断裂带１９条；圈定隐伏、半隐伏酸性—超基性岩体３８个，半隐伏地层５处，推断火山构造一个；把测区火山岩基底划分为三大区，将Ⅱ区又进一步划分为３个次级区；圈定成矿远景预测区５个；通过重力剖面地壳模型计算，得出本区地壳分上、中、下三层，属富硅富铝的大陆型地壳。

Petrogenesis of Mesozoic granitoids and volcanic rocks in South China： A response to tectonic evolution

This paper summarizes the new results on the petrogenesis of Mesozoic granitoids and volcanic rocks in South China. The authors propose that these rocks were formed in time and space as a response to regional tectonic regime change from the continent-continent collision of the Indosinian orogeny within the broad Tethyan orogenic domain in the Early Mesozoic （T1-T3） （Period Ⅰ） to the largely extensional setting as a result of the Yanshanian orogeny genetically associated with the NW-WNW-ward subduction of the paleo-Pacific oceanic lithosphere in the Late Mesozoic （J2-K2） （Period Ⅱ）. Of the Period I Indosinian granitoids, the early （T1-T2^1） ones are syn-collisional, and formed in a compressional setting; the late （T2^2-T3） ones are latecollisional, and formed in a locally extensional environment. During the Period Ⅱ Yanshanian magmatism, the Early Yanshanian （J2-J3） granitoid-volcanic rocks, which are distributed mainly in the Nanling Range and in the interior of the South China tectonic block （SCB）, are characteristic of rift-type intraplate magmatism, whereas the Late Yanshanian K1 granitoidovolcanic rocks are interpreted as genetically representing active continental margin magmatism. The K2 tholeiitic basalts interlayered with red beds are interpreted as genetically associated with the development of back-arc extensional basins in the interior of the SCB. The Yanshanian granitoid-volcanic rocks are distributed widely in South China, reflecting extensional tectonics within much of the SCB. The extension-induced deep crustal melting and underplating of mantle-derived basaltic melts are suggested as the two principal driving mechanisms for the Yanshanian granitic magmatism in South China.

Distinguishing volcanic lithology using Self-Organizing Map

Self-Organizing Map is an unsupervised learning algorithm.It has the ability of self-organization,self-learning and side associative thinking.Based on the principle it can identified the complex volcanic lithology.According to the logging data of the volcanic rock samples,the SOM will be trained,The SOM training results were analyzed in order to choose optimally parameters of the network.Through identifying the logging data of volcanic formations,the result shows that the map can achieve good application effects.

Preparation and characterization of Martian soil simulant NEU Mars-1

To develop Martian soil simulant,basalts of the Chahar volcanic group in Wulanchabu,Inner Mongolia,China were selected as the simulant initial materials,which were ground and sorted to a predetermined particle size ratio,and small amounts of magnetite and hematite were added.The main phases of NEU Mars-1 simulant were plagioclase,augite and olivine.The glass transition and crystallization temperatures of NEU Mars-1 were 547.8 and 795.7°C,respectively.The complex dielectric constant,magnetic conductivity(0.99-1.045),and dielectric loss tangent angles(0.0025-0.030)of NEU Mars-1 were all stable in the frequency range of 2-18 GHz.Mossbauer spectroscopy results showed that the mass ratio of Fe2+to Fe3+in the simulant was 77.6:22.4.The NEU Mars-1 Martian soil simulant demonstrated particle size ratio,chemical composition,phase composition,thermal stability,and dielectric property similar to Martian soil,and can be used as the substitute material to extract oxygen and metals with in-situ resource utilization technologies.

小德营子乡膨润土矿成矿特征分析

区内的断裂构造较发育,主要为北东向逆冲断层,均属燕山期断裂。现已发现有F1、F2二条主要断层。本区的膨润土矿为层控矿产,成矿方式为陆相火山沉积,属火岩碎屑岩-再造型矿。

Petroleum exploration of shallow marine deposit Carboniferous volcanic tuff reservoir in the western margin of Junggar Basin

In 2011, petroleum exploration of shallow marine deposits Carboniferous and volcanic tuff reservoir re- alized breakthroughs at Chepaizi slope in the western margin of Junggar Basin. Pal 61 well, with 855.7 949.6 m section, in the conventional test oil obtained 6 t/d industrial oil flow. The surface viscosity is 390 mPa. s （50 ℃）. The marine deposit of Carboniferous are deep oil source rocks and high-quality reservoir. Magma volcanic activity provides the basis for volcanic reservoir development and distribution. The weathering crust and secondary cracks developed volcanic tuff by strong rock weathering and dissolution of organic acids which has become top quality reservoir. Deep Permian oil-gas migrated and accumulated to high parts along Hong-Che fault belt and stratigraphic unconformity stripping. Permian and Triassic volcanic rocks or dense mudstone sedimentary cover as a regional seal for the late Carboniferous oil-gas to save critically. The seismic pre-stack time migration processing technologies for the problem of poor inner structures of Carboniferous were developed. Response of volcanic rock seismic and logging are obvious. The application imaging logging and nuclear magnetic technology achieved the qualitative identification and quantification of fracture description.

Controlling the effect of a distant extremely thick igneous rock in overlying strata on coal mine disasters

Based on theoretical analysis, similarity simulation tests, numerical simulation analysis and field observations, we analyzed rock collapse and rules of fraction evolution of overlying rocks and studied the rules in controlling the effect of an extremely thick igneous rock, found above a main mining coal seam in an area prone to coal mine disasters in the Haizi Coal Mine. The results show that this igneous rock, called a "main key stratum", will not subside nor break for a long time, causing lower fractures and bed separations not to close. The presence of igneous rock plays an important role in rock bursts, mine floods, gas outburst and surface subsidence in coal mines. By analyzing the rules in controlling the effect of this igneous rock, we provide useful references for safety and high efficiency mining in coal mines under special geological conditions.

Log evaluation of fractured igneous reservoirs in Songliao Basin

The petrophysical parameters are bad in most igneous reservoirs of Songliao Basin because of the very low porosity and permeability.The evaluation of igneous reservoirs has not been fully studied so far.The current technique of formation evaluation and interpretation used in sedimentary formations face a series of problems and difficulties.In this study,The PCA was used to identify lithology,a multi-mineral model "QAPM" was proposed."Surface effect" must be considered when evaluating saturation.A software "SIMPLE" was developed and was used to deal with the logging data in over 70 wells with good results were achieved.

Geochemistry and tectonic significance of volcanic rocks from Qushenla Formation in Gerze area of northern Tibetan Plateau

By using petrological,isotope chronological,and geochemical methods,the authors studied the volcanic rocks in the studied area,mainly including dacites and trachytes. The results show that they formed during the late Early Cretaceous. Geochemically,the volcanic rocks are relatively enriched in large-ion lithophile elements( Rb,K,and Th) and depleted in high field strength elements( Nb,Ta,and Ti),and rich in light rare earth elements,and depleted in heavy rare earth elements. The fact indicates that the main body of the volcanic rocks in the Qushenla Formation was derived from the partial melting of lower crust. The lithological assemblages are characterized by continental high-K calc-alkaline and shoshonitic series,suggesting that the southward-subducting oceanic slab in southern Bangong Lake had break off and that the Bangong Lake-Nujiang Ocean had closed before 107 Ma. The main dynamic mechanisms for the genesis of this set of intermediate-acidic volcanic rocks were upwelling of the asthenosphere and partial melting of the lower crust caused by slab break-off.

Distributive characteristics of reservoirs and exploration potential associated with intrusive rocks of Yingcheng Formation in Yingtai rift depression, NE China

Petroleum geologists have paid great attentions to the volcanic reservoirs of Songliao Basin in NE Chi- na. There are plenty of subvolcanic rocks in the Songliao Basin accompanying the Early Cretaceous Yingeheng Formation. The logging data show the good reservoir potential of these intrusive rocks but the distribution char- acteristics and formation mechanisms of these reservoirs are not clearly understood. Based on the previous stud- ies by using coring, cuts and logging data of Yingtai rift depression, the reservoirs＇ characteristics of intrusive rocks are presented. There are two types of intrusive rocks namely the syenodiorite-porphyrite and diabase which occur as laccolith and/or sill, both having the characteristics of low gamma and high density with little primary porosity and permeability. The prevalent reservoir porosity is the secondary porosity, such as spongy/cavernous pore, tectonic fracture. The laboratory data of porosity of diabase can reach 6.7%, but the permeability is less than 0.6 x 10-3μm2, median pressure is high, indicating that the pore throat of this kind reservoir is small. The maximum logging porosity is about 12%. The change of porosity does not correlate to the buried depth. It is the major significant differences in the distributive characteristics compared to the normal sedimentary rock reservoirs. Most of intrusive rocks underwent alteration diagenesis whilst some were subjected to precipitation diagenesis. The spongy and cavernous pore can be formed during the alteration processes of plagioclase to illite and pyroxene to chlorite. The secondary porosity is greatly correlated with the alteration intensity of matrix, pla- gioclase and pyroxene. There are pyroxenes and more plagioclases in diabase, which cause the higher alteration intensity than the syenodiorite-porphyrites in the same acid fluid. So the porosity of diabase is higher than that of syenodiorite-porphyrites. The top or/and bottom part of intrusive rocks develop the higher porosity. Because those parts are easy to contact formation fluid, and the shrink fractures give the more surface for reaction be- tween fluid and rock. The porosity of intrusive rocks is same to the volcanic rocks in Yingtai rift depression and Xujiaweizi rift depression which bear the prolific gas. It suggests good reservoir potential. Intrusive rocks are hosted by the dark mudstone which indicates semi-deep and deep lake facies belt.

Geology and geochemistry of Huanggangliang stratabound skarn deposit in Inner Mongolia,China

Over the recent three decades, exploration of a large-size Sn-Fe polymetallic ore deposit at the Huanggangliang, the Da Hinggan Mountains, Inner Mongolia, China, has been largely focused on the premise that the mineralization represents epigenetic magmatic hydrothermal ore deposit in genetic connection with the Mesozoic magmatism. The Huanggangliang Sn-Fe polymetallic ore deposits occurred in Permian strata, with silt- stone/marble of the Zhesi Formation and spilite/andesite/tuff of the Dashizhai Formation. The characteristics of geological and geochemical data demonstrated that sedimentary hydrothermal mineralization occurred during the basin evolution at the Permian, rather than representing epigenetie magmatic hydrothermal genesis with the following evidences. The ore-bearing skarus are stratiform with underlying metasedimentary rocks and overlying volcanic sedimentary rocks. Sedimentary hydrothermal textures and structures are observed in the stratabound ore-bearing skarn such as bedded-laminated skarn and magnetite ores with small-size folding or soft deforma- tion, synsedimentary breccia of skarn and magnetite ores and concentric shell structure of magnetite ores. So the stratabound ore-bearing skarns associated with magnetite ore and micro-disseminated tin, are peculiar examples of exhalite. The REE contents of the stratabound ore-bearing skarns display ∑LREE-rich （36.91×10^-6） but EHREE-depletion （6. 42 ×10^-6） , with positive Eu anomaly （Eu/Eu ＊ 1.28） and negative Ce anomaly （Ce/ Ce ＊ 0.88 ） , which is totally different from REE pattern of the Huanggang magmatic rocks（ with ∑REE 277.73 ×10^-6, ELREE 220.24 ×10^-6, ∑HREE 57.49 ×10^-6, Eu/Eu＊ 0.06, Ce/Ce＊ 1.52） , which is comparable with modern sea-floor hydrothermal fluid,sedimentary hydrothermal ore deposit and associated hydrothermal sedimentary rocks. Calcite samples with δ13CPDB from -5. 400 ‰ to -4. 397 ‰ and δ18SOSMOW from 9. 095 ‰ to 9. 364 ‰ in the stratabound ore-bearing skarns show sedimentary hydrothermal genesis of the Huanggangliang deposit. This proposition is useful not only for interpretation of the genesis of the Huanggangliang large Sn-Fe polymetallic ore deposit but also significant for mineral exploration in the area especially for finding large deposits caused by sedimentary exhalative mineralization processes.

Geochemical characteristics and genesis of volcanic and sub-volcanic rocks from porphyrite-type iron deposits in Ningwu metallogenic province,eastern China:Constraints from elements

Ningwu porphyrite-type iron deposits are located in Ningwu Mesozoic volcanic basin,which belongs to the middle and lower reaches of the Yangtze River metallogenic province.The volcanic rocks can be divided into Longwangshan,Dawangshan,Gushan and Niangniangshan Formations from early to late.All these volcanic rocks are rich in alkali,and show the similar patterns in rare earth element(REE) distribution.However,some differences can be found in the trace elements and REE patterns.The study of petrology and REE geochemical characteristics shows that these rocks are derived from the underplating of the lithospheric mantle and are contaminated by crustal materials,undergo AFC process during the magmatic evolution.

Division and correlation of Yixian Formation in western Liaoning,China

The Yixian Formation is a series of volcanic-sedimentary rocks in Biepiao area of Liaoning Province. It is mainly composed of basic and intermediate-basic volcanic lava,pyroclasts and terrestrial sedimentary rocks. Based on the regularity of volcanic activity,the Yixian Formation was divided by the present authors into four members in ascending order:the first member is of basal conglomerate,basic and intermediate-basic volcanic rocks; the second member is of lake phrase sedimentary rocks,or in another word,precious fossil-rich sedimentary beds; the third is of basic volcanic rocks; and the fourth is of upper conglomerate. Field mapping and comprehensive study also indicate that there are abundant vertebrate fossils (mainly of Psittacosaurus) in the first member of the Yixian Formation,and the Jehol Biota (including Sinosauropterxy,Confuciusorns sanctus,Archaefructus,etc.) is yielded in the second member of Yixian Formation. From west to east,the volcanic activity of Yixian Formation changed regularly from early to late,and from basic and intermediate-basic to acid (alkali).

The Dayingzi detachment fault system in Liaodong Peninsula and its regional tectonic significance

Large scale lithosphere thinning is an important characteristic of the destruction of the North China Craton （NCC） during the late Mesozoic. A series of extensional structures were developed under extensional setting, among which is the Dayingzi detachment fault system （DFS）. The DFS is constituted by three parts, volcano-sedimentary basins at the hanging wall, the Dayingzi-Huanghuadian detachment fault zone, and Paleoproterozoic metamorphic rock series and Mesozoic plutons at the footwall. In the section across the detachment fault zone, there is a sequence of tectonites including fault gouge, microbreccia, cataclastic-mylonites, mylonites, and gneissic biotite monzonite granite. Microstructural characteristics of tectonites and electron backscatter diffraction （EBSD） patterns of quartz indicate that the rocks from the footwall experienced a process from upper greenschist facies to lower greenschist facies. SHRIMP and LA-ICP MS U-Pb dating of zircons from the volcanic rocks in the basins, the tectonic evolution of the DFS is summarized as follows： 1） regional extension started at 135.0±1.2 Ma ago, when the detachment fault cut through the middle crust. Faulting induced the upwelling of magma and eruption of volcanic rocks and deformed a series of medium-acid volcanic rocks; 2） after 135.0±1.2 Ma, a large scale detachment faulting was active cross-cutting the mid-upper crust. The western margin of Jurassic and Triassic granite was ductilly and brittly sheared; besides, the Cretaceous volcanoedimentary rocks were tilted when the master fault approached the surface; 3） at around 127±1 Ma, the detachment fault stopped its activity and was intruded by the unsheared Cretaceous granite near Chaoyang. Comparison with the Liaonan metamorphic core complex （MCC） and other extensional structures in Liaodong Peninsula led to a general trend of including three zones in the Peninsula： MCC zone, detachment fault systems （DFS） zone, and half graben zone. MCC commonly cuts through the mid-lower crust, DFS through the mid-upper crust, and half graben through the upper crust. Therefore, development of the extensional structures in Liaodong Peninsula indicates that they are the results of crustal extension and thinning at different crustal levels. They may provide a deep insight into the dynamic mechanism, history of destruction and lithosphere thinning of the North China Craton （NCC）. Liaodong Peninsula, detachment fault system, Cretaceous extension, lithosphere thinning, North China Craton

Timing of the formation of the Tianhuashan Basin in northern Wuyi as constrained by geochronology of volcanic and plutonic rocks

The Tianhuashan Basin is one of the most important volcanic basins in the northern Wuyi,southeastern China,comprising two successive volcanic units,the Daguding Formation and the overlying Ehuling Formation,along with several small associated igneous intrusions.The Lengshuikeng super-large-scale Ag-Pb-Zn deposit,which is closely related to these volcanic-intrusive rocks,is located in the northwestern part of the basin.In order to understand the basin evolution and magmatism,we determined LA-ICP-MS U-Pb zircon ages for the volcanic successions and associated intrusive rocks.U-Pb zircon dating of volcanic units yielded precise ages of 144±1 Ma for crystal tuff in the lower member of the Daguding Formation,142±1 Ma for andesite within the upper member of the Daguding Formation,140±1 Ma for tuffite of the first(i.e.,lowermost) member of the Ehuling Formation,and 137±1 Ma for rhyolitic ignimbrite within the third volcano-stratigraphic member of the Ehuling Formation.Three types of intrusive igneous rocks(quartz syenite porphyry,K-feldspar granite porphyry,and rhyolite porphyry) yielded precise weighted mean 206 Pb/238 U ages of 144±1,140±1,and 140±1 Ma,respectively,suggesting that these intrusions along with the aforementioned volcanics were all emplaced during the Early Cretaceous.In addition,the weighted mean 206 Pb/238 U ages determined on zircon from two samples of a granite porphyry intrusion,which hosts ore mineralization of the Lengshuikeng Ag-Pb-Zn deposit,are 158±1 and 157±1 Ma,indicating emplacement in the Late Jurassic.These new geochronological results for igneous rocks of the Tianhuashan Basin constrain the timing of volcanic and plutonic activity in the basin,and have important implications for our understanding the tectonic history of the region,and for identifying metallogenic types and the timing of ore deposition of the Lengshuikeng deposit.

The discovery of Palaeoproterozoic volcanic rocks in the Bulunkuoler Group from the Tianshuihai Massif in Xinjiang of Northwest China and its geological significance

In the Dabudaer region of the Tianshuihai Massif （Xinjiang, Northwest China）, metavolcanic rocks within the mainly meta- sedimentary Bulunkuoler Group are basalt, basaltic andesite, and rhyolite. In situ zircon U-Pb LA-ICP-MS dating on rhyolite magmatic zircons yielded an age of 2481±14 Ma, interpreted as the eruption age of the Bulunkuoler Group volcanic rocks. The basalt and basaltic andesite are low-A1 tholeiite series and the rhyolite is low-Al calc-alkaline series. All of rocks are charac- terized by enrichment of LREE and LILE （Rb, Th and Ba）, depletion of P, Nb, Ta and Ti, and absence of Eu anomalies. The Cnd（t） of basalts ranges from 3.14 to 4.88 indicating a depleted mantle source. The trace element signatures show that these magmas experienced intense crustal contamination during their ascent. Direct evidence for crustal contamination is the xenocrystic zircons in the ryholite, with ages back to ca. 3300 Ma. The primitive-mantle normalized and Zr/Y-Zr diagrams for the basic volcanic rocks show that they formed in an intra-continental tectonic setting. Combined with the previous studies and compared with North China Craton Neoarchean basic volcanic rocks, it is supposed that the Bulunkuoler Group volcanic rocks reflect the Palaeoproterozoic mantle magma underplating and interaction with felsic crust.

The absolute paleoposition of the North China Block during the Middle Ordovician

Present-day hot spots and Phanerozoic large igneous provinces(LIPs) and kimberlites mainly occur at the edges of the projections of Large Low Shear Wave Velocity Provinces(LLSVPs) on the earth's surface. If a plate contains accurately dated LIPs or kimberlites, it is possible to obtain the absolute paleoposition of the plate from the LIP/kimberlite and paleomagnetic data. The presence of Middle Ordovician kimberlites in the North China Block provides an opportunity to determine the absolute paleoposition of the block during the Middle Ordovician. In addition to paleobiogeographical information and the results of previous work on global plate reconstruction for the Ordovician Period, we selected published paleomagnetic data for the North China Block during the Middle Ordovician and determined the most reasonable absolute paleoposition of the North China Block during the Middle Ordovician: paleolatitude of approximately 16.6°S to 19.1°S and paleolongitude of approximately 10°W. The block was located between the Siberian Plate and Gondwana, close to the Siberian Plate. During the Cambrian and Ordovician periods, the North China Block may have moved toward the Siberian Plate and away from the Australian Plate.