Chemical characterization of naturally weathered oil residues in the sediment from Yellow River Delta, China

With its close proximity to Shengli Oilfield, China’s second largest oilfield, the Yellow River Delta is at high risk for crude oil contamination. The massive oil discharge in oilfield may offer a chance for a natural experiment to investigate compositional changes of oil residues and study the stability of source- and weathering-dependent molecular parameters in oil residues after spills. The results demonstrate that the conventional diagnostic ratios, such as C₂₉20S/(20S + 20R), C₂₉/C₃₀H, C₃₀βα/αβ, C₃₁22S/(22S + 22R), C₂-DBTs/C₂-PHENs, C₃-DBTs/C₃-PHENs, DBT/MCHRY, CHRY/PHENs, are also valid for oil source identification even after extensive weathering of spilled oils in terrestrial environment, although some exceptions were encountered for extensively weathered sample. Moreover, the ratios of selected specific biomarkers (the oleanane index, the gammacerane index) have been developed and assessed as source indicators. Finally, we find that some maturity parameters based on alkyl naphthalenes and methyl phenanthrenes in petroleum geochemistry, such as the methylnaphthalene ratios (TMNr, TeMNr, PMNr), the methylphenanthrene ratios (MPI-1, MPDF), can be applied for the source identification and correlation at their lightly to moderately weathered stage.     

A tectono-genetic model for porphyry–skarn–stratabound Cu–Au–Mo–Fe and magnetite–apatite deposits along the Middle–Lower Yangtze River Valley, Eastern China

The Middle–Lower Yangtze River Valley metallogenic belt (YRB), situated along the northern margin of the Yangtze craton, is characterized by porphyry–skarn–stratabound Cu–Au–Mo–Fe deposits in the areas of uplift and magnetite–apatite deposits in Cretaceous fault basins. Following detailed field investigations and a review of published data, we recognize two episodes of magmatism and mineralization in the YRB: 1) 156–137 Ma high-K calc-alkaline granitoids associated with 148–135 Ma porphyry–skarn–stratabound Cu–Au–Mo–Fe deposits and 2) 135–123 Ma shoshonitic series, associated with 134.9–122.9 Ma magnetite–apatite deposits. A-type granitoids and associated alkaline volcanic have a small age range from 126.5 to 124.8 Ma and are temporally, spatially and genetically associated with the second episode. The geodynamic history of the YRB did not experience the Paleozoic to Mesozoic lithospheric thickening that took place in the North China craton. This process is inferred to be linked to partial melting of the delaminated lower crust at high pressures, resulting in the development of C-type adakitic rocks. The petrochemical and Sr/Nd isotopic data show that both the shoshonitic series and A-type granitoids are quite different from adakites, with only some of the K-calc-alkaline granitoids having adakitic signatures. Previous ore genesis models were established based on an assumed relationship with adakites and a continuous tectono-thermal evolution from 150 to 100 Ma.All data obtained for the Middle–Lower Yangtze River region consistently show that the Tan–Lu regional strike-slip fault zone, initiated at 233 ± 6 to 225 ± 6 Ma from the collision between the North China and Yangtze cratons and was reactivated at ca. 160 Ma. The Tan–Lu fault was caused by the oblique subduction of the Izanagi plate, which along the YRB the low-angle subducted slab and the overlying crust was disrupted or broken due to the disharmonious movement of the two blocks. The high-K calc-alkaline granitoids magmas were derived from melting of the subducted slab, with some input of crustal material. These magmas were emplaced at the intersections between NE- and EW-trending faults and formed porphyry–skarn–stratabound Cu–Au–Mo–Fe deposits between 156 and 137 Ma. After 135 Ma the subducted plate changed its direction of motion to northeast, now running parallel to the Eurasian continental margin, and leading to large-scale continental extension. The shoshonitic series and subsequent A-type granitoids magmatism and the development of magnetite–apatite ores in the YRB, took place in both fault basins and NE-trending rifts between 135 and 124 Ma.     

Temperature Control on Soluble Reactive Phosphorus in the Lower Mississippi River?

Soluble reactive phosphorus (SRP) has recently been shown to be one of the limiting nutrients for the growth of phytoplankton in the northern Gulf of Mexico. We show here that during the past decade, SRP concentrations in the lower reaches of North America's largest river, the Mississippi River, were highest in summer and lowest in winter and positively correlated with water temperature. Upstream data showed this coupling to increase in a downstream trend in the Mississippi main stem. Water quality data analysis and phosphorus mass balances were conducted to examine the controls of this relationship. The results showed that the positive SRP–temperature correlation in the Mississippi River system was largely a result of gradual dilution of SRP-enriched upper Mississippi River waters, which contributed most to the Mississippi River during summer, by SRP-depleted waters from the Ohio and other tributaries. Particle buffering and organic matter mineralization might play a role in the observed SRP–temperature relationship, but their importance relative to tributary effects is not quantified. Future work on the seasonal dynamics of SRP in large river systems needs to consider the effects of both tributary dilution and in situ processes.     

http://www.sciencedirect.com/science/article/pii/S1674987111000399

Using a Diamond Anvil Cell combined with micro Raman spectroscopy,the quantitative relations among Raman shifts,pressure and temperature were obtained for the vibration of O-H in H₂O-NaCl,C-O in CO₃^2-,S-O in SO₄^2- and C-H in n-heptane-cyclohexane.Based on the quantitative relationships obtained,it is possible to determine the inner pressure for single fluid inclusions and to further determine the isochore of the systems.It is not only helpful to obtain the forming temperatures and pressures of the enclosing minerals,but also to be able to provide information concerning the chemical compositions of the fluid inclusions.     

青藏高原土壤热交换的计算方案及初步分析

从地温满足的热传导方程出发,导出了计算土壤平均和瞬时热通量的计算方案。该计算方案可同时计算出土壤热通量随时间和随深度的变化。它利用整层的地温信息来计算任一层的热通量,这种方案克服了用差分方案进行直接计算的局限性。然后使用中日亚洲季风观测实验期间的地温自动观测站资料和相应的常规观测资料,计算了青藏高原上土壤热通量及其变化,结果表明,不论是常规观测站还是自动观测站,其结果与青藏高原第一次观测实验所用热流板的直接观测结果是相近的,因而这种计算方案是实用而有效的。     

老龄化背景下候鸟旅游移民迁移驱动力 ——以三亚为例

以三亚为例,基于对256位候鸟旅游移民的实地调研,采用因子分析及方差分析等方法,探讨了候鸟旅游移民迁移驱动力的结构、强度及群体差异.结果表明:1)三亚候鸟旅游移民经济收入和文化水平相对较高,但也存在显著的内部差异;2)三亚候鸟旅游移民迁移驱动力由风景环境、社会资本、社会象征、城市服务、生活方式、家庭氛围及健康养生等7个...     

荆州市郊土壤中铅来源的同位素示踪研究

对荆州市郊的农田区、交通区和工业区土壤、汽车尾气、染料和煤等样品进行了铅含量和铅同位素组成研究。铅含量分析结果表明,工业区和交通区土壤均已受到一定的铅污染,其Pb含量平均值(32.80μg/g和26.28μg/g)均高于中国土壤平均值,但工业区受到的铅污染更严重。农田区土壤的Pb含量平均值(24.84μg/g)虽稍低,但也指示该区部分土壤已开始受到铅污染。土壤酸溶相Pb含量与全土Pb含量成显著正相关,指示土壤中的Pb主要分布在酸溶相中。铅同位素组成分析结果表明,工业区、交通区和农田区土壤以及土壤不同相(全土、土壤酸溶相和残渣相)具有不同的Pb同位素组成,且土壤的 206 Pb/204 Pb 和 208 Pb/204 Pb 比值大致具有如下规律: 土壤残渣相>全土>土壤酸溶相。但是,全土的两组Pb同位素比值平均值更接近于酸溶相的。煤、汽车尾气和染料等环境样品具有比土壤变化范围更大的Pb同位素组成。 208 Pb/204 Pb 与 206 Pb/204 Pb 相关关系图显示,土壤酸溶相大致位于残渣相、汽车尾气和染料与煤组成的三角形内,表明土壤同时受到了汽车尾气、染料和煤的影响。综合对比分析所有样品的Pb含量和Pb同位素组成,结果表明自无Pb汽油的使用,交通区的Pb污染已大大降低,但工业区受到的Pb污染在加重。为防止土壤铅污染的进一步加重,今后需重点防范工业Pb的排放与污染。     

高邮凹陷永安地区戴南组一段储层特征及主控因素

通过岩心、铸体薄片、扫描电镜、物性分析和孔隙图像分析等资料,对高邮凹陷永安地区戴南组一段砂岩储层特征进行了系统分析,从沉积和成岩两方面对储层物性主控因素进行了研究。研究结果表明:岩石类型为长石岩屑砂岩,成分成熟度较低,粒度偏细,分选中等偏差; 储层物性以低孔低渗为主中孔中渗为辅,孔隙类型有粒间孔、粒间溶孔、粒内溶孔和铸模孔,平均孔径为37.53 μm,喉道主要为可变端面的收缩部分,其次为片状和弯片状喉道,平均喉道半径为10.25 μm,孔喉配位数主要为3,分选性好。沉积作用是高邮凹陷永安地区戴南组一段砂岩储层物性主控因素之一,水动力强分选程度高的沉积环境形成的砂岩粒度大分选好,储层物性好; 不同的成岩作用类型对储层物性具有不同的控制作用,压实和胶结作用导致储层孔隙空间变小,物性变差,而溶蚀作用形成次生孔隙空间,储层物性得到改善,在2 500～2 700 m和2 850～2 950 m处形成了明显的次生孔隙发育带。     

面向地质图的知识图谱构建及智能问答应用

海量地质图件蕴含着丰富的地学基础知识及专家经验知识。地质图主要表达了通过区域地质调查、矿产地质调查所获取的地球表面的地质知识（如地层单元、岩体、断裂等）。如何快速地从矢量地质图件中抽取地质知识并形成知识服务是目前地学知识图谱及知识服务研究的前沿。由于传统的地质图知识抽取主要依赖人工方式进行综合分析,本文聚焦于矢量地质图件知识表达与抽取研究,提出了一种地质图知识表达框架,提取地质图中所包含的地质实体及关系,将地质图信息以知识图谱的形式表达,并开展了基于地质矢量知识图谱的智能问答应用。最后以江西省于都县银坑幅矢量数据集为例开展实验验证分析,结果表明,本文方法能够较为全面地获取地质图中各个地质对象的信息,提高了地质图语义表达的效果,同时也可以提高地质学习人员对地质图的理解和认识,让计算机能够大规模获取地质图的知识内容。

     

伽师强震群区上地壳三维速度层析成像

以伽师强震群为中心布设了一个50km60km范围的三维人工地震透射临时台阵,接收来自不同方位的8次爆破激发产生的地震波;利用所记录到的莫霍界面临界反射P 波、S波走时,采用模型不分块反演技术,重建台阵下方上地壳三维P,S波速度扰动图象,以及vp/vs扰动分布图象;并结合伽师震群的地震活动分布,对该震群的成因进行了分析．结果表明,研究区上地壳存在明显的不均匀性．自12ｋｍ 深度开始,在与震群震中相应的位置上,明显出现沿北北西向的高Ｐ波速度块体,在它的周围为相对低速分布,这种结构上的差异是伽师强震群发生的最直接原因;vp/vs在相同的位置上为高值分布,则表明由于介质相对软弱可能造成震源体抗剪强度下降．这可作为伽师强震群发震特点的一种解释．