常量元素氧化物含量及其比值揭示的中晚全新世以来玛曲高原的环境演变

对玛曲高原具有代表性的黄土-古土壤-风成砂剖面(OL剖面)常量元素氧化物含量及其比值的地球化学特征分析表明:(1)常量元素氧化物总含量为91.93%且SiO₂(67.93%) >Al₂O₃(11.2%) >Fe₂O₃(3.97%) >CaO(3.76%)>K₂O(2.16%) >Na₂O(1.81%) >MgO(1.1%);(2)玛曲高原处于较弱的脱Ca、Na初级风化阶段,并伴有碳酸盐的淋失;(3)玛曲高原的气候经历了冷干-凉润-温湿-凉干的冷暖旋回。依据常量元素氧化物含量及其比值揭示的环境特征并结合¹⁴C测年将玛曲高原中晚全新世以来的环境演变划分为4.6 ka BP以前的风沙活动强烈期、4.6～4.3 ka BP的风沙活动较弱期、4.3～0.3 ka BP的固结成壤期和0.3 ka BP至今的风沙活动增强期4个阶段。     

基于TRACK的GPS海浪测量方法

针对现有GPS海浪测量技术的不足,提出基于TRACK的GPS海浪测量方法,即利用TRACK解得海上载体高精度的垂向位移,经浪潮分离提取海浪信号,采用周期图法估计海浪信号的功率谱,计算海浪要素。利用实测数据进行实验,结果表明,平均波高和平均周期与测波仪结果差异分别小于2 cm和0.25 s,验证了本文方法的有效性。     

在CorelDRAW平台上进行Fry法有限应变测量的新技术

有限应变测量是韧性变形定量估算的主要手段。Fry法有限应变测量以变形颗粒,如变形砾石、鲕粒、近等轴矿物等为应变标志体,地质实践中较容易获得,是岩石有限应变测量的最普遍手段。其传统测量过程极为繁琐,难以满足大范围应变测量的要求,数据精度也较低,限制了Fry法的应用。前人曾根据Fry法原理设计了计算机程序,但其程序相关编程语言如今已基本不能使用。本研究基于目前地质上较普遍使用的制图软件CorelDRAW平台的VBA编程,设计出一个基于CorelDRAW平台的Fry法应变测量宏程序FRY-1。在新图层上将所有变形颗粒的中心点标出后,运行FRY-1宏程序即可快速得到精确的Fry图解,并计算出相对精确的R值。通过实例与“最邻近心对心法”的测量结果进行的对比,证明该方法简便易操作,并可大幅提高有限应变测量的效率和有效减小误差。     

藏北羌塘盆地QK-1井中侏罗统烃源岩地球化学特征

QK-1天然气水合物钻探试验井位于西藏羌塘盆地毕洛错地区,主要钻遇中侏罗统夏里组粉砂质泥岩和布曲组灰岩。其有机质丰度、有机质类型、有机质成熟度等有机地球化学特征表明,南羌塘地区中侏罗统烃源岩的有机质丰度偏低,夏里组泥岩TOC介于0.26%~0.38%之间,达到差-中烃源岩标准,而布曲组灰岩TOC介于0.02%~0.08%之间,仅局部达到差烃源岩标准;两个组的烃源岩有机质类型主要为Ⅱ₂型及Ⅲ型,较利于天然气的生成,其中夏里组的生气能力优于布曲组;该区烃源岩热演化程度较高,Ro为1.31%~1.63%之间,均达到高成熟阶段,而夏里组有可能已进入干气阶段。基于冻土区天然气水合物成藏条件分析,综合考虑夏里组烃源岩及沉积厚度特征,认为中侏罗统夏里组具备良好的天然气水合物勘探前景。     

地震记录的时间域反褶积、仿真及在地震计方位角相对测量中的应用

介绍了一种用冲击不变法从速度响应平坦地震计二阶传递函数设计得到的递归滤波方法,比用双线性变换得到的递归滤波系数少,因此使用更方便.作者用此方法作了反褶积与仿真的数值实验和实际地震记录的短周期仿真试验,仿真结果与实际仪器记录符合较好;并将此法应用于地震计方位角的相关分析法相对测量,结果与不仿真的相关分析测量相比更接近寻北仪的绝对测量结果.     

Kelp Gulls (Larus dominicanus) killed and injured by discarded monofilament lines at a marine recreational fishery in northern Patagonia

Among marine debris, monofilament fishing lines often result in negative impacts on marine organisms. We characterized marine debris and incidence of lost and discarded monofilament lines along beaches used by recreational fishers, and report the impact of lines on Kelp Gulls (Larus dominicanus) at the Bahía San Blas protected area, site of one of the main shore-based recreational fisheries of the southwestern Atlantic. Over 55% of the marine debris recorded originated from recreational fishing activities. Balls of tangled monofilament lines were found at a rate of 40.5 items per km. A total of 27 adult Kelp Gulls were found entangled with monofilament. All individuals were tangled to vegetation within colony boundaries. Four of the gulls had a monofilament line protruding from the bill, showing that they may be also killed when trying to obtain bait. Our results indicate that lost or discarded monofilament lines in the Bahía San Blas recreational fishing area result in undesired impacts on coastal wildlife.     

Deep-sea faunal communities associated with a lost intermodal shipping container in the Monterey Bay National Marine Sanctuary,CA

Carrying assorted cargo and covered with paints of varying toxicity, lost intermodal containers may take centuries to degrade on the deep seafloor. In June 2004, scientists from Monterey Bay Aquarium Research Institute (MBARI) discovered a recently lost container during a Remotely Operated Vehicle (ROV) dive on a sediment-covered seabed at 1281 m depth in Monterey Bay National Marine Sanctuary (MBNMS). The site was revisited by ROV in March 2011. Analyses of sediment samples and high-definition video indicate that faunal assemblages on the container’s exterior and the seabed within 10 m of the container differed significantly from those up to 500 m. The container surface provides hard substratum for colonization by taxa typically found in rocky habitats. However, some key taxa that dominate rocky areas were absent or rare on the container, perhaps related to its potential toxicity or limited time for colonization and growth. Ecological effects appear to be restricted to the container surface and the benthos within ∼10 m.     

Simulation of scree‐slope dynamics: investigating the distribution of debris avalanche events in an idealized two‐dimensional model

We present a two‐dimensional model of the development of scree slopes using the discrete‐element method. We concentrate on the dynamics of the accumulating debris at the cliff foot rather than on the failure modes of the cliff‐face or shape of the underlying rock surface. The evolution of this unconsolidated material is intermittent and systematically changing over time, with an early high disturbance regime, dominated by a characteristic event size (where 65% of particles in the debris are in motion to some extent), replaced at later times by many shallow slides interspersed with infrequent large events that involve motion through almost the full scree depth. These large slides lead to a stratigraphy in which the layers of material are stretched almost horizontal near the base of the slope. The scree surface thus shows a gradient in age with most recent rock‐fall close to the cliff and the oldest rock‐fall debris outcropping at the foot. The final surface slope tends to show little curvature, and the final mean slope is well correlated with the angle of internal friction of the particles, although the change is very small over a wide range of friction angles [final slope (in degrees relative to horizontal) ~ 0.043 × internal friction angle + 17.49, with a correlation coefficient of 0.89, p‐value 0.0001]. Some weak size‐segregation of the debris is found, but this seems to have little to do with individual particles bounding down the slope. The shape of the rock core agrees largely with the analytic forms given by Fisher–Lehmann and Bakker–Le Heux expressions, but the original simple Fisher quadratic can give the best fit. Overall the evolution shows a remarkable insensitivity to the model parameters, suggesting that the controls on dry scree‐slope evolution are primarily geometric in character. Copyright © 2014 John Wiley & Sons, Ltd.     

大连地磁台天文方位角测量

论述大连地磁台天文方位角的测量原理、方法及观测结果,在地磁观测室未封顶的条件下,能在观测墩直接观测北极星,避免比测墩转角换算等因素增加的观测误差,观测精度提高.     

Geochemical evolution during the cracking of crude oil into gas under different pressure systems

Two comparative simulation experiments(a normal atmospheric-pressure opening system and a 20 MPa closed system)were conducted to study the geochemical evolution of n-alkane,sterane,and terpane biomarkers in the process of oil cracking into gas under different pressures.With an initial experimental temperature set at 300°C,the temperature was increased to 650°C at a heating rate of 30°C/h.The products were tested every 50°C starting at 300°C,and a pressure of 20 MPa was achieved using a water column.The low-maturity crude oil sample was from the Paleogene system in the Dongying sag in eastern China.The threshold temperature obtained for the primary oil cracking process in both pressure systems was 450°C.Before the oil was cracked into gas,some components,including macromolecular n-alkanes,were cracked into medium-or small-sized n-alkanes.The secondary oil cracking of heavy hydrocarbon gases of C2–5to methane mainly occurred between 550°C to 650°C,and the parameters Ln(C1/C2)and Ln(C1/C3),as well as the dry coefficients,increased.Overpressure inhibited the oil cracking process.In the 20 MPa system,the oil conversion rate decreased,the temperature threshold for gas generation rose,and oil cracking was inhibited.Compared with the normal pressure system,high-carbon n-alkanes and other compounds in the 20 MPa pressure system were reserved.Furthermore,the parameters∑C21-/∑22+,Ln(C1/C2),and Ln(C1/C3),as well as the dry coefficients,decreased within the main temperature range.During secondary oil cracking(550°C to 600°C),the Ph/nC18and Pr/nC17decreased.High pressure influenced the evolution of the biomarkers Ts and Tm,C31homohopane,C29sterane,and their related maturity parameters to different extents during oil cracking under different temperature ranges.