塔里木盆地柯坪地区志留系砂岩储层成岩与成藏过程

近年来,塔里木盆地柯坪地区志留系发现工业油气流,但该地区构造演化复杂,勘探程度低,油气成藏研究薄弱.以新苏地1井为例,通过薄片观察、阴极发光、包裹体岩相学、荧光光谱和显微测温实验,分析柯坪地区志留系砂岩储层的成岩作用、孔隙演化和成藏过程.结果表明,柯坪地区志留系砂岩储层发育两期油气包裹体：第一期为黄色荧光油气包裹体,早于石英加大边的形成;第二期为蓝色荧光油气包裹体,伴生有沥青、气‒油‒沥青包裹体,反映了天然气和原油混合形成凝析油气和稠油沥青沉淀的过程.柯坪志留系成藏过程经历了3个阶段：第一阶段为晚海西期来自奥陶系正常油的充注;第二阶段为印支晚期‒燕山早期,来自于寒武系的高成熟干气与来自奥陶系的正常油发生混合形成凝析油藏和稠油沥青;第三阶段为燕山晚期‒喜山期,油气藏经历调整改造,靠近活动性强的沙井子断裂附近油气藏被破坏,远离活动性断裂的斜坡带油气藏得以保存.     

Comparison of Blast-Induced Damage Between Presplit and Smooth Blasting of High Rock Slope

This paper focuses on the comparison of damage induced by smooth blasting and presplit blasting based on the excavation of high rock slope. The whole damage process of the smooth blasting and presplit blasting excavation method is studied by using a cumulative blasting damage numerical simulation technology based on the secondary development of the dynamic finite element code LS-DYNA. The results demonstrate that, in the case of contour blasting with the method of smooth blasting, the total damage of rock slope is a result of cumulated damage induced by the production hole, buffering hole, and smooth hole. Among the total damage, the blasting of the production hole is the main resource, followed by the smooth and buffering holes. For the presplit blasting, the final damage of rock slope is mainly induced by presplit blasting itself. The spatial distribution characteristics of the final damage zone of two methods are compared. Two classes of damage zone could be found in smooth blasting excavation; one of them is the columnar high-degree damage zone around the slope surface and the other is the low-degree damage zone located in the middle of the slope. But in the case of presplit blasting, there is only the columnar high-degree damage zone around the slope surface. Finally, a damage control suggestion for two blasting excavation methods is proposed and verified based on the excavation of the temporary shiplock slopes of the Three Gorges Project in China.     

华东部分铀矿区内大气和饮用水体放射性水平调查研究

通过对华东地区２１ 个铀矿区内居民居住环境大气中氡及其子体α潜能浓度的调查,结果表明：居民居室外氡浓度均值范围为６．７３—１３２．９ Ｂｑ／ｍ ３,氡子体α潜能浓度均值范围为１１．０—７８．８ｎＪ／ｍ ３。居室内的平均氡浓度均值范围为１４．５—１８５．８ Ｂｑ／ｍ ３,氡子体α潜能浓度均值范围为１３．８—１０４．２ ｎＪ／ｍ ３;对居民饮用水源的取样分析表明,铀浓度均值范围为０．１２—１．６８ μｇ／Ｌ,钍浓度均值范围为０．０２—０．４２ μｇ／Ｌ,镭－２２６ 浓度均值范围为０．９０—１２．１ ｍ Ｂｑ／Ｌ,与全国和当地的放射性天然本底水平比较接近,均属正常本底水平。     

Microseism Induced by Transient Release of In Situ Stress During Deep Rock Mass Excavation by Blasting

During deep rock mass excavation with the method of drill and blast, accompanying the secession of rock fragments and the formation of a new free surface, in situ stress on this boundary is suddenly released within several milliseconds, which is termed the transient release of in situ stress. In this process, enormous strain energy around the excavation face is instantly released in the form of kinetic energy and it inevitably induces microseismic events in surrounding rock masses. Thus, blasting excavation-induced microseismic vibrations in high-stress rock masses are attributed to the combined action of explosion and the transient release of in situ stress. The intensity of stress release-induced microseisms, which depends mainly on the magnitude of the in situ stress and the dimension of the excavation face, is comparable to that of explosion-induced vibrations. With the methods of time–energy density analysis, amplitude spectrum analysis, and finite impulse response (FIR) digital filter, microseismic vibrations induced by the transient release of in situ stress were identified and separated from recorded microseismic signals during a blast of deep rock masses in the Pubugou Hydropower Station. The results show that the low-frequency component in the microseismic records results mainly from the transient release of in situ stress, while the high-frequency component originates primarily from explosion. In addition, a numerical simulation was conducted to demonstrate the occurrence of microseismic events by the transient release of in situ stress, and the results seem to have confirmed fairly well the separated vibrations from microseismic records.     

Petrogenesis of the concealed Daqiling intrusion in Guangxi and its tectonic significance: Constraints from geochemistry,zircon U-Pb dating and Nd-Hf isotopic compositions

The samples from the hidden Daqiling muscovite monzonite granite, which has recently been recognized within the Limu Sn-polymetallic ore field, have been analyzed for zircon U-Pb ages and whole rock geochemical and Nd-Hf isotopic compositions to discuss its genesis, source, and tectonic setting. LA-ICP-MS zircon U-Pb dating indicates that the granite crystallized in the late Indosinian (224.8±1.6 Ma). The granite is enriched in SiO₂ and K₂O and low in CaO and Na₂O. It is strongly peraluminous with the A/CNK values of 1.09–1.20 and 1.4 vol%–2.7 vol% normal corundum. Chondrite-normalized REE patterns show slightly right-dipping shape with strongly negative Eu anomalies (δEu =0.08–0.17). All samples show enrichment of LILEs (Cs, Rb and K) and HFSEs (U, Pb, Ce and Hf), but have relatively low contents of Ba, Sr and Ti. The zircon saturation temperatures (T _zr) are from 711 to 740°C, which are slightly lower than the average value of typical S-type granite (764°C). The granite has negative ? _Nd(t) and ? _Hf(t) values, which change from ?9.1 to ?10.1 with the peak values of ?9.2 to ?9.0 and from ?3.7 to ?12.6 with the peak values of ?6 to ?5, respectively. The T _DM ^C (Nd) and T _DM ^C (Hf) values are 1.74–1.82 Ga with the peak values of 1.73–1.75 Ga and 1.49–2.04 Ga with the peak values of 1.5–1.6 Ga, respectively. These characteristics reveal that the source region of the granite is dominantly late Paleoproterozoic to early Mesoproterozoic crustal materials. Seven inherited magmatic zircons are dated at the age of 248.6±4.3 Ma, which suggests the existence of the early Indosinian granite in Limu area. These zircons have the ? _Hf(t) values of ?6.7–?2.3, similar to those of the Daqiling granite, implying the involvement of the early Indosinian granite during the formation of the Daqiling granite. Inherited zircon of 945±11 Ma has the ? _Hf(t) and T _DM(Hf) values of 8.7 and 1.14 Ga, respectively, compatible with those of the Neoproterozoic arc magmatic rocks in the eastern Jiangnan orogenic belt. Therefore we inferred that Neoproterozoic arc magma might have been involved in the formation of the Daqiling granite, and that the Neoproterozoic arc magma belt and continent-arc collision belt between the Yangtze and Cathaysia Blocks might have extended westsouthward to Limu region. It is proposed that the underplating of mantle materials triggered by crustal extension and thinning resulted in partial melting of crustal materials to form the Daqiling granite in the late Indosinian under post-collisional tectonic setting.     

台湾浅滩西部水域海洋动物的石油烃含量和荧光光谱特征

本文报道了台湾浅滩西部水域鱼类、虾类和软体头足类动物的总石油烃含量,分析了主3类动物样品的荧光光谱特征,并将本文数据与南海其他水域海洋动物的石油烃含量作了比较。     

Soil amplification based on seismometer array and microtremor observations in Chiba,Japan

Soil amplification characteristics of earthquake ground motion were investigated in terms of peak ground acceleration and transfer function based on the Chiba array observation records. The amplification of peak ground acceleration occurred mostly at the top soft layer and was similar for the three components. The effects of non-linear response of soil deposits on the transfer function were examined. Transfer functions calculated by ensemble average were close for the two horizontal components while those obtained from a smoothing operation were generally different. Both the transfer functions from the ensemble average and the smoothing operation underestimated the gain factor around the natural frequencies. A two-step smoothing procedure was proposed and a rotary spectrum was used to improve the estimation of the transfer function. Microtremors were observed at the locations of the boreholes where seismometers are buried. The power spectrum and spatial coherency of the microtremors were compared with those of the earthquake ground motion. Emphasis was placed on the wavetypes which dominated the peaks in the power spectra.     

空间无碰撞激波的数值研究

无碰撞激波是空间等离子体和宇宙等离子体中的重要物理现象。文中评述了数值研究空间无碰撞激波的两种方法－粒子模拟和混合模拟,给出了准垂直和准平行无碰撞激波的数值研究结果。还指出了一些尚未解决的研究问题。     

绥化台地电阻率异常与龙镇震群

分析研究绥化地电台近十年地电观测资料,认为1986年发生在德都龙镇的中强震群,绥化台地电阻率存在趋势异常,并明显呈现短临异常前兆特征。同时,指出绥化台地电阻率趋势异常的继续存在及其周围250km范围内仍有发生中强地震的可能。