Kema terrane: A fragment of a back-arc basin of the early Cretaceous Moneron–Samarga island-arc system, East Sikhote–Alin range, Russian Far East

Abstract The Kema terrane is a suite of Barremian(?)–Aptian to Albian volcano-sedimentary rocks of Sikhote–Alin that are interpreted as deposits of the back-arc basin of the Moneron–Samarga island-arc system. Compositional features of the different-type deposits indicate a near-slope depositional environment influenced by volcanic processes. Studies of slump fold orientation testify to the accumulation of material from southeast to northwest by gravitational sliding. Compositional characteristics of terrigenous rocks suggest the major provenance for detrital material was an ensialic volcanic island arc. Petrochemical characteristics of basaltic rocks indicate that the formations studied were confined to the back part of the arc.     

饶河杂岩中枕状玄武岩的锆石U－Pb年代学、地球化学及其地质意义

那丹哈达增生杂岩为中国东部古太平洋板块俯冲最为可靠的地质记录之一,对限定古大洋板块的西向俯冲具有重要的理论意义.饶河杂岩位于那丹哈达增生杂岩的核心位置,发育典型的增生杂岩组合,其中玄武岩类多呈构造透镜体状产出于超镁铁质-镁铁质杂岩带,变形轻微,没有遭受变质.对饶河杂岩中枕状玄武岩样品进行的同位素年代学和地球化学研究结果表明：饶河杂岩中枕状玄武岩锆石LA-ICP-MS U-Pb年龄为中侏罗世（168±2 Ma）,枕状玄武岩大离子亲石元素Rb、Sr亏损,高场强元素Nb、Ta富集,Th元素丰度较高,形成于洋岛（OIB型）环境.饶河杂岩中枕状玄武岩的形成时代和成因环境,对于该区侏罗纪时期构造动力学背景研究具有意义.     

井筒及围岩应力,应变观测方法研究

采用最新研制的岩体应力、应变匹配传感器对西安立井煤柱开采引起的井筒附加应力特别是对井筒穿过断层附近产生的附加应力进行了较系统的观测，并对观测结果进行了分析和总结。     

Interactions between basalts and oil source rocks in rift basins： CO2 generation

Basalts interbedded with oil source rocks are discovered frequently in rift basins of eastern China, where CO2 is found in reservoirs around or within basalts, for example in the Binnan reservoir of the Dongying Depression. In the reservoirs, CO2 with heavy carbon isotopic composition (δ13C>-10‰ PDB) is in most cases accounts for 40% of the total gas reserve, and is believed to have resulted from degassing of basaltic magma from the mantle. In their investigations of the Binnan reservoir, the authors suggested that the CO2 would result from interactions between the source rocks and basalts. As the source rocks around basalts are rich in carbonate minerals, volcanic minerals, transition metals and organic matter, during their burial history some of the transition metals were catalyzed on the thermal degradation of organic matter into hydrocarbons and on the decomposition of carbonate minerals into CO2, which was reproduced in thermal simulations of the source rocks with the transition metals (Ni and Co). This kind of CO2 accounts for 55%-85% of the total gas reserve generated in the process of thermal simulation, and its δ13C values range from -11‰- -7.2‰ PDB, which are very similar to those of CO2 found in the Binnan reservoir. The co-generation of CO2 and hydrocarbon gases makes it possible their accumulation together in one trap. In other words, if the CO2 resulted directly from degassing of basaltic magma or was derived from the mantle, it could not be accumulated with hydrocarbon gases because it came into the basin much earlier than hydrocarbon generation and much earlier than trap formation. Therefore, the source rocks around basalts generated hydrocarbons and CO2 simultaneously through catalysis of Co and Ni transition metals, which is useful for the explanation of co-accumulation of hydrocarbon gases and CO2 in rift basins in eastern China.     

珲春市草帽顶子矿泉水评价

草帽顶子矿泉水为偏硅酸矿泉水．含有钴、锶等多种人体必需的微量元素,是一处优质天然矿泉水。起源于大气降水．矿化时间约15年．流量较大,具有重要的开发利用价值．     

大兴安岭南段早二叠世两类火山岩岩石地球化学特征及其构造意义

大兴安岭南段二叠系大石寨组发育两套火山岩，即林西地区拉斑玄武岩系列的细碧－角斑岩类和大石寨地区钙碱性岩石系列玄武岩和玄武安山岩类。细碧岩的主元素以富铁为特征，成分类似于N－MORB，微量元素表现为岛弧拉斑玄武岩的地球化学特征。细碧岩类形成于大石寨裂陷槽强烈拉张的中心位置，是地幔源区较高程度部分熔融的产生。大石寨地区玄武岩和玄武安山岩类的化学成分表现为大陆缘弧火山岩的地球化学特点，形成于大石寨裂隙槽拉张中心以外的环境，是地幔物质较低程度部分熔融和地壳物质严重混染的产物。大石寨裂隙槽中火山岩的这种独特的成分和组合特点可能反映了裂隙槽的形成是一个快速而短暂的强烈拉张过程。     

西准噶尔玛依勒地区枕状玄武岩年代学、地球化学及岩石成因

通过对造山带内洋岛玄武岩的时代及地球化学性质研究,不仅可以进行古海山/大洋高原的识别,而且还可以进行古洋盆演化及古构造格局恢复。笔者等最新在西准噶尔玛依勒山北侧识别出一套枕状玄武岩,其与火山碎屑岩、硅质岩共生。枕状玄武岩斜长石微晶普遍发育中空骸晶结构,是在水下熔岩急剧萃冷条件下迅速结晶的产物。通过LA-ICP-MS锆石U-Pb测年,获得枕状玄武岩206Pb/238U加权平均年龄为437.2±2.2Ma,该年龄的获得填补了志留纪碱性玄武岩的空白。岩石地球化学分析结果显示,玛依勒枕状玄武岩为碱性玄武岩系列,岩石具有中等Si O2(44.89%~47.81%),高Ti O2(3.28%~4.12%)及P2O5(0.50%~0.70%),低Mg O(3.49%~6.79%),轻、重稀土元素分异较为明显((La/Yb)N=5.5~7.3),无明显Eu异常(Eu/Eu*=0.96~1.06),相对富集Rb、Th、U,亏损Ba、K、Sr,没有明显Nb、Ta负异常,这些地球化学特征与洋岛玄武岩(OIB)极其相似。微量元素含量及反映源区性质的比值表明,枕状玄武岩来源于富集地幔源区,主要组成为尖晶石和石榴石二辉橄榄岩,并发生了5%±的部分熔融,其形成于大洋板内与地幔柱有关的海山/大洋岛屿环境。结合前人研究,认为西准噶尔乃至古亚洲洋在中古生代洋内俯冲的同时,大洋板内可能存在地幔柱活动。     

Rate of strike-slip motion on the Amanos Fault (Karasu Valley, southern Turkey) constrained by K–Ar dating and geochemical analysis of Quaternary basalts

The left-lateral Amanos Fault follows a 200-km-long and up to 2-km-high escarpment that bounds the eastern margin of the Amanos mountain range and the western margin of the Karasu Valley in southern Turkey, just east of the northeastern corner of the Mediterranean Sea. Regional kinematic models have reached diverse conclusions as to the role of this fault in accommodating relative motion between either the African and Arabian, Turkish and African, or Turkish and Arabian plates. Local studies have tried to estimate its slip rate by K–Ar dating Quaternary basalts that erupted within the Amanos Mountains, flowed across it into the Karasu Valley, and have since become offset. However, these studies have yielded a wide range of results, ranging from 0.3 to 15 mm a⁻¹, which do not allow the overall role and significance of this fault in accommodating crustal deformation to be determined. We have used the Cassignol K–Ar method to date nine Quaternary basalt samples from the vicinity of the southern part of the Amanos Fault. These basalts exhibit a diverse chemistry, which we interpret as a consequence varying degrees of partial melting of their source combined with variable crustal contamination. This dating allows us to constrain the Quaternary slip rate on the Amanos fault to 1.0 to 1.6 mm a⁻¹. The dramatic discrepancies between past estimates of this slip rate are partly due to technical difficulties in K–Ar dating of young basalts by isotope dilution. In addition, previous studies at the key locality of Hacılar have unwittingly dated different, chemically distinct, flow units of different ages that are juxtaposed. This low slip rate indicates that, at present, the Amanos Fault takes up a small proportion of the relative motion between the African and Arabian plates, which is transferred southward to the Dead Sea Fault Zone. It also provides strong evidence against the long-standing view that its slip continues offshore to the southwest along a hypothetical left-lateral fault zone located south of Cyprus.     

Soft rock pillars

Summary Soft rock pillars can be designed by several methods available in the mining literature. All of these methods include the effect of shape, or geometry, on the average strength of specimens and pillars. All of the pillar design methods include some measurement of the strength of specimens of the pillar rock. The most common rock specimen strength property measured is the unconfined compressive strength. However, the average strength of triaxially confined rock specimens is much greater than the unconfined specimen strength, which can be more important to pillar strength. The estimation of the strength of a pillar is complicated by the decrease in rock specimen strength with increase in specimen size.Editor's note: In common with North American engineering practise, the paper uses English units throughout, where feasible conversions are included in the text. Where not, the following factors may be used: 1 inch=25.4 mm; 1 ft=0.3048 m; 1 lbf/in.^–2=6.895 kn/m^–2; 1Tonf.=8.896 kN.     

玄武岩盖层下石林的岩溶动力学特征

受玄武岩盖层的影响，石林地区的地下水在雨季和旱季对碳酸盐岩都具有侵蚀性，玄武岩盖层空气CO2呈现出低—高—低的双向变化梯度。溶蚀试验表明．地下0～0．6m，水平方向的溶蚀量大于垂直方向的溶蚀量，而随着深度的增加，垂直方向的溶蚀量大于水平方向。富含CO2的水通过具有最大渗透张量和较小主轴倾角的玄武岩裂隙下渗，对碳酸盐岩的溶蚀作用表现为一个脱钙、富铝铁、硅迁移的复杂过程，并在地下0～0．6m形成许多水平凹槽、穿洞等岩溶形态，而地表0．6m以下以垂向溶蚀为主，有利于石柱的形成与发育。