滇西高黎贡变质岩带南段淡色花岗岩脉年代学特征及构造意义

高黎贡构造带作为藏东三江地区大地构造上的一条重要构造带,在印度-欧亚板块碰撞过程中起着重要的调节作用,并被认为是该地区发生"大陆逃逸"与地块旋转的西边界。本文以高黎贡构造带中的深变质岩为研究对象,通过对高黎贡变质岩带南段进行详细地构造解析,发现其内部广泛发育一系列或顺岩石面理、或切割面理分布的淡色花岗岩脉;并选取了5个淡色花岗岩脉样品进行锆石U-Pb测年,这5个样品的锆石~(206)Pb/~(238)U年龄值主要分布于二个区间:68~40Ma和24~21Ma,并在45Ma左右形成一个巨大的峰值。基于锆石的晶形、晶内结构和微量元素组成特征等方面进行锆石成因学分析,认为本文所测试的5个淡色花岗岩脉样品的锆石为深熔作用过程中形成的锆石;从而推测高黎贡变质岩带南段发生深熔作用并形成淡色花岗岩脉的时代主要集中于68~40Ma和24~21Ma。     

Pore pressure assessment from well data and overpressure mechanism: Case study in Eastern Tunisia basins

Abstract

Independent and complementary methods were used for pore pressure assessment in the eastern Tunisian basins. Drilling data and surveys allow settling the pore pressure profile in these basins. The main used parameters are mud weights, formation pressure surveys, drilling parameters, well logs, fluids exchange with formation and borehole issues. In the eastern Tunisia platform, the pore pressure profiles show changes in overpressure magnitude in all the three dimensions of the basin (location and depth/stratigraphy). We highlighted two overpressure intervals form bottom to top: The late Cretaceous in the North-eastern part, and the Tertiary overpressure interval hosted in the Palaeocene to Miocene series. The structural analysis of overpressure location shows that the Tertiary interval is likely to have originated in a disequilibrium compaction in Cenozoic grabens. Pore pressure cross sections and maps confirm the link between active normal faults that segmented the basin to grabens and highs and pore pressure anomalous area. In the Senonian interval, we noted mature source-rocks that can explain the overpressure in the late Cretaceous interval. In addition, the recent to active compressive tectonics may have contributed to both pore pressure anomaly generations. The fluid overpressures characterization in the eastern Tunisian sedimentary basins helps in hydrocarbons exploration. Indeed, the overpressure interval in the reservoir levels stimulates and improves the production in the oilfields and contributes to hydrocarbon trapping. Moreover, the adequate prediction of pore pressure profile contributes to reduce drilling cost and enhance the drilling operations safety.     

开链冠醚2，6-二(8''''-喹啉氧甲基)-4-甲基-苯甲醚及其Ag( Ⅰ )、Cu( Ⅱ )、Ni( Ⅱ )配合物的合成与性质研究

设计合成一种尚未见文献报道的酚醚型双臂开链冠醚化合物L(L=2,6-二(8’-喹啉氧甲基)-4-甲基-苯甲醚)，经元素分析、IR、1HNMR、MS等方法确定了其组成和结构。其Ag(Ⅰ)、Cu(Ⅱ)、Ni(Ⅱ)固体配合物的元素分析结果表明金属离子不同，则其配合物的配位比(M∶L)不同，Ag(Ⅰ)配合物为1∶1，Cu(Ⅱ)、Ni(Ⅱ)配合物为2∶3。并运用热重-差热分析对其热稳定性进行初步研究。     

Quantitative mapping of active mud volcanism at the western Mediterranean Ridge-backstop contact

Based on a new quantitative analysis of sidescan sonar data combined with coring, we propose a revised model for the origin for Mediterranean Ridge mud volcanism. Image analysis techniques are used to produce a synthetic and objective map of recent mud flows covering a 640 × 700 km² area, which represents more than half of the entire Mediterranean Ridge mud belt. We identify 215 mud flows, extruded during the last 37,000–60,000 years. This time period corresponds to the limit of penetration of the sonar, that we evaluate through geoacoustic modeling of the backscattered signal returned by the mud breccia-hemipelagites contact, and calibrate by coring. We show that during this period, at least 96% of the mud volume has been extruded at the Mediterranean Ridge-Hellenic backstop contact, the remaining being scattered over the prism. We suggest that the source is a Messinian (5–6 Ma) mud reservoir that remained close to the backstop contact, at variance with the classical transport-through-the-wedge model. A revised mud budget indicates that steady-state input is not needed. We propose that the source layer was deposited in deep and narrow pre-Messinian basins, sealed by Messinian evaporites, and finally inverted in post-Messinian times. Onset of motion of the Anatolia-Aegea microplate in the Pliocene resulted in change from slow to fast convergence, triggering shear partitioning at the edges of the backstop and basin inversion. Mud volcanism initiation is probably coeval with the latest events of this kinematic re-organization, i.e. opening of the Corinth Gulf and activation of the Kephalonia fault around 1–2 Ma.     

Magnetic characterization of a retroarc extensional basin: The Loncopué Trough

The Loncopué Trough is a Pliocene to Quaternary extensional basin developed over the hinterland area of the Southern Central Andes. This basin is bounded by two neotectonic extensional fault systems delimiting a narrow topographic low. Previous studies have mostly focused on structural and geochemical aspects of this feature. However, geophysical surveys, aimed to unravel deep structure beneath a thick-younger than 5 My volcanic coverage, are scarce and based their interpretations on low resolution data sets. In this study, we collected new aeromagnetic data with the objective of characterizing the magnetic properties of the crust in the Loncopué Through and nearby zones. Additionally, we analyze the spatial relation between geological structures, volcanic fields and magnetic data. In order to highlight the boundaries of the magnetic sources and calculate the basement depth, we applied derivative techniques and the source parameter imaging. Also, we estimated an effective susceptibility model using the Magnetization Vector Inversion method, which takes into account the combined effects of remanence and induced magnetization. To determine the thermal structure of the area, we calculated the Curie depth points through the spectral analysis technique. From the analysis of magnetic data we were able to characterize the main structures and lineaments associated with this retroarc extensional trough. Notably, only the Loncopué eastern fault system seems to be a crustal-scale tectonic feature, while E-W-, ENE- and ESE-trending lineaments are interpreted as relatively minor structures segmenting the basement. Finally, our susceptibility model, together with the analysis of the Curie point, revealed potential magmatic/hydrothermal reservoirs in the Copahue volcano, and the Codihue and Cajón de Almanza regions that could be connected at depth forming a regional magmatic body.     

Sequences Characterization of Microsatellite DNA Sequences in Pacific Abalone(Haliotis discus hannai)

1 Introduction Microsatellites or simple sequence repeats (SSRs) are tandemly repeated motifs of one to six bases found in all prokaryotic and eukaryotic genomes analysed to date (Zane et al., 2002). Due to their hyper-variable and co-dominant nature, relatively high abundance and random distribution in the genome, microsatellites are among the most efficient class of molecular markers. Such repeats display high polymorphism because of variation in repeat length and can be rapidly analysed t…     

Fine-grained landuse characterization using ground-based pictures: a deep learning solution based on globally available data

ABSTRACT

We study the problem of landuse characterization at the urban-object level using deep learning algorithms. Traditionally, this task is performed by surveys or manual photo interpretation, which are expensive and difficult to update regularly. We seek to characterize usages at the single object level and to differentiate classes such as educational institutes, hospitals and religious places by visual cues contained in side-view pictures from Google Street View (GSV). These pictures provide geo-referenced information not only about the material composition of the objects but also about their actual usage, which otherwise is difficult to capture using other classical sources of data such as aerial imagery. Since the GSV database is regularly updated, this allows to consequently update the landuse maps, at lower costs than those of authoritative surveys. Because every urban-object is imaged from a number of viewpoints with street-level pictures, we propose a deep-learning based architecture that accepts arbitrary number of GSV pictures to predict the fine-grained landuse classes at the object level. These classes are taken from OpenStreetMap. A quantitative evaluation of the area of Île-de-France, France shows that our model outperforms other deep learning-based methods, making it a suitable alternative to manual landuse characterization.     

Biodegradative potential and characterization of psychrotolerant polychlorinated biphenyl-degrading marine bacteria isolated from a coastal station in the Terra Nova Bay (Ross Sea, Antarctica)

Antarctic marine bacteria were screened for their ability to degrade polychlorinated biphenyls (PCB) as the sole carbon and energy source at both 4 degrees C and 15 degrees C. PCB-degrading isolates (7.1%) were identified by sequencing their 16S rDNA as Pseudoalteromonas, Psychrobacter and Arthrobacter members. One representative isolate per genera was selected for evaluating the biodegradative potential under laboratory scale and phenotypically characterized. Removal of individual PCB congeners was between 35.6% and 79.8% at 4 degrees C and between 0.4% and 82.8% at 15 degrees C. Differences in the removal patterns of PCB congeners were observed in relation to the phylogenetic affiliation: Arthrobacter isolate showed similar biodegradation efficiencies when growing at 4 degrees C and 15 degrees C, while Pseudoalteromonas better degraded PCBs at 15 degrees C. No biodegradation was detected for Psychrobacter isolate at 4 degrees C. Results obtained highlight the occurrence of PCB-degrading bacteria in Antarctic seawater and suggest the potential exploitation of autochthonous bacteria for PCB bioremediation in cold marine environments.     

A Markov Chain Model for Subsurface Characterization: Theory and Applications

This paper proposes an extension of a single coupled Markov chain model to characterize heterogeneity of geological formations, and to make conditioning on any number of well data possible. The methodology is based on the concept of conditioning a Markov chain on the future states. Because the conditioning is performed in an explicit way, the methodology is efficient in terms of computer time and storage. Applications to synthetic and field data show good results.     

Stiff soil amplification effects in the 7 September 1999 Athens (Greece) earthquake

The Athens, Greece, earthquake of 7 September 1999 provided a number of reliable strong motion recordings and well-defined patterns of damage at sites with known geological and geotechnical conditions. Joint evaluation of this evidence shows that the very stiff soils of the Athens basin, compared to the nearby outcropping soft rocks, have amplified the peak horizontal acceleration by an average of 40% or more and have shifted elastic response spectra to higher periods. US and the European seismic code provisions (NEHRP-97 and EC-8), place stiff soils and soft rocks at the same site category and consequently fail to predict these adverse effects. A larger number of site categories and new site coefficients that depend on the seismic excitation frequency appear necessary in order to overcome this deficit of the codes.