Young (late Amazonian), near-surface, ground ice features near the equator, Athabasca Valles, Mars

A suite of four feature types in a ∼20 km² area near 10° N, 204° W in Athabasca Valles is interpreted to have resulted from near-surface ground ice. These features include mounds, conical forms with rimmed summit depressions, flatter irregularly-shaped forms with raised rims, and polygonal terrain. Based on morphology, size, and analogy to terrestrial ground ice forms, these Athabascan features are interpreted as pingos, collapsing pingos, pingo scars, and thermal contraction polygons, respectively. Thermal Infrared Mapping Spectrometer (THEMIS) data and geological features in the area are consistent with a sedimentary substrate underlying these features. These observations lead us to favor a ground ice interpretation, although we do not rule out volcanic and especially glaciofluvial hypotheses. The hypothesized ground ice that formed the mounds and rimmed features may have been emplaced via the deposition of saturated sediment during flooding; an alternative scenario invokes magmatically cycled groundwater. The ground ice implicit in the hypothesized thermal contraction polygons may have derived either from this flooding/ground water, or from atmospheric water vapor. The lack of obvious flood modification of the mounds and rimmed features indicates that they formed after the most recent flood inundated the area. Analogy with terrestrial pingos suggests that ground ice may be still extant within the positive relief mounds. As the water that flooded down Athabasca Valles emerged via a volcanotectonic fissure from a deep aquifer, any extant pingo ice may contain evidence of a deep subsurface biosphere.     

A novel CFAR tonal detector using phase compensation

A novel tonal detector is presented in this paper. The detector uses phase compensation for detecting sinusoidal signal with unknown amplitude, frequency, and phase in complex Gaussian noise with unknown variance. We analyze the statistical properties of the discrete Fourier transform (DFT) of the observations and consider the leakage effect. Then we develop the detector by using generalized likelihood ratio test (GLRT). The new detector fully utilizes the phase information of the signal and achieves constant false alarm rate (CFAR) property. Theoretical analysis and simulation results show its improvement in detection performance.     

Oil and Gas Distribution in Hailar Basin,Northeast China

Through petroleum exploration of 20 years, a new petroleum production area has been constructed in Hailar Basin. Their petroleum geological characteristics and hydrocarbon distribution has been known in detail. The Hailar Basin is a basin group consisted of many scattered sub-basins with similar structural developed history. Each sub-basin has unique hydrocarbon distributing rules, including (1) oil/gas reservoir distribution is controlled by the oil/gas sag, and the oil/gas bearing in big sag is rich; (2) underwater fan and turbidity fan are the most favorable reservoirs; structure zone controlled by main fault is favorable zone of forming composite oil/gas accumulation; (3) lower fault-block in higher rise and higher fault-block in lower rise are favorable to oil/gas accumulation; (4) deep fault and granite body are closely related to oil/gas reservoir, its distributing area is favorable area of oil and mantle source non-hydrocarbon gas formation;(5) higher geothermal area is favorable oil/gas bearing area.     

Late Cenozoic deformation subsequence in northeastern margin of Tibet —Detrital AFT records from Linxia Basin

Two events of Tibet uplifting are revealed by detrital apatite fission track (AFT) age data from Linxia Basin. They occurred at about 14 and 5.4-8.0 MaBP respectively. We interpret the first one to be related to the uplifting of the northern Tibet, which might have resulted from convectively removing the thickened lower lithosphere. The second one is a result of Laji Mountain uplifting. Numerous studies of the Tibetan Plateau suggest that the onset time of the deformation in the northeastern margin of Tibetan Plateau and the time of Tibet attaining to its present elevation is about 8 MaBP. They are approximately coincident with the uplift of Lajishan Mountain. It suggests that the northeastern margin of Tibet propagated northeastwardly to its present site in about 8 MaBP for accommodating the sustained convergence between India-Eurasia plate and for keeping its high elevation. The active block pattern dominating the strong earthquake distribution of Chinese continent probably formed at about 8.0-5.4 MaBP.

     

新疆西天山莱历斯高尔-3571斑岩铜钼矿田地质地球化学和成矿年代

新疆西天山斑岩型矿床面临找矿攻坚,重要铜钼矿化研究十分必要.近年在毗邻莱历斯高尔钼矿新发现3571铜矿,构成重要铜钼矿田.研究认为,莱历斯高尔-3571铜钼矿田形成于准噶尔洋壳向南俯冲在哈萨克斯坦-伊犁板块东北缘形成的早石炭世陆缘弧环境中.矿田内强烈角岩化的志留系粉砂泥岩中侵入了花岗闪长斑岩小岩体群,伴随陆缘弧构造-岩...     

柴达木地块北缘全吉地块钾长石浅粒岩碎屑锆石LA-ICP-MSU-Pb定年——对达肯大坂岩群时代的约束

为查明全吉地块基底中达肯大坂岩群的最大沉积年龄,用LA-ICP-MS技术测定了钾长石浅粒岩中的锆石U-Pb年龄。CL图像和Th/U比值指示这些锆石均为岩浆成因的锆石。36个测点207Pb/206Pb年龄变化范围为2094～2280Ma,其中年龄谐和度高于90%的30个测点的207Pb/206Pb年龄相对概率密度曲线呈单峰分布特征,峰值年龄为2190Ma左右。结合全吉地块最早一期变质事件的年龄,钾长石浅粒岩原岩碎屑和所在的达肯大坂岩群的沉积年龄范围被约束在1.95～2.19Ga之间。本研究表明,前人在侵入于达肯大坂岩群的伟晶岩脉中获得的约2.42Ga年龄的锆石应捕获于围岩,属于继承性岩浆碎屑成因,该类锆石年龄不能用来约束达肯大坂岩群原岩的最小沉积年龄。     

Volatile organic compounds decomposition using nonthermal plasma coupled with a combination of catalysts

A series of experiments were performed for toluene decomposition from a gaseous influent at normal temperature and atmospheric pressure by nonthermal plasma coupled with a combination of catalysts technology. Nonthermal plasma was generated by dielectric barrier discharge. γ-Al₂O₃ was used to be a sorbent and a catalyst carrier. Nanocatalysts were MnO₂/γ-Al₂O₃ coupled with modified ferroelectric of nano-Ba_0.8Sr_0.2Zr_0.1Ti_0.9O₃. γ-Al₂O₃ played an important role in prolonging reaction time of nonthermal plasma with volatile organic compounds molecules. MnO₂/γ-Al₂O₃ has an advantage for ozone removal, while nano-Ba_0.8Sr_0.2Zr_0.1Ti_0.9O₃ is a kind of good ferroelectric material for improving energy efficiency. Thus these packed materials were incorporated together to strengthen nonthermal plasma power for volatile organic compounds decomposition. The results showed the synergistic technology resulted in greater enhancement of toluene removal and energy efficiencies and a better inhibition for ozone formation in the gas exhaust. Based on the data analysis of the Fourier transforms infrared spectrum, the reaction process of toluene decomposition and the mechanism of synergistic effect are discussed. The results showed in a complex oxidation mechanism of toluene via several pathways, producing either ringretaining or ringopening products. The final products were carbon dioxide and water.     

北京规划新城区域工程地质勘查方法体系研究

为了全面实现《北京城市总体规划（2004年—2020年）》对顺义等11个新城的规划目标,我们系统开展了11个规划新城的区域工程地质勘查工作。为了进一步降低第四系沉积物覆盖、地表建筑物及各种管线等因素对勘查方法有效性和可靠性的不利影响,本文研究和建立了一套适合于北京规划新城的区域工程地质勘查方法体系,该方法体系包括顺义式、门头沟式和延庆式三类,对全国其他地区开展区域工程地质勘查,具有重要的参考价值和示范作用。