Joint inversion of temperature,vitrinite reflectance and fission tracks in apatite with examples from the eastern North Sea area

As sediment accumulation indicates basin subsidence, erosion often is understood as tectonic uplift, but the amplitude and timing may be difficult to determine because the sedimentary record is missing. Quantification of erosion therefore requires indirect evidence, for example thermal indicators such as temperature, vitrinite reflectance and fission tracks in apatite. However, as always, the types and quality of data and the choice of models are important to the results. For example, considering only the thermal evolution of the sedimentary section discards the thermal time constant of the lithosphere and essentially ignores the temporal continuity of the thermal structure. Furthermore, the types and density of thermal indicators determine the solution space of deposition and erosion, the quantification of which calls for the use of inverse methods, which can only be successful when all models are mutually consistent. Here, we use integrated basin modelling and Markov Chain Monte Carlo inversion of four deep boreholes to show that the erosional pattern along the Sorgenfrei–Tornquist Zone (STZ) in the eastern North Sea is consistent with a tectonic model of tectonic inversion based on compression and relaxation of an elastic plate. Three wells in close proximity SW of the STZ have different data and exhibit characteristic differences in erosion estimates but are consistent with the formation of a thick chalk sequence, followed by minor Cenozoic erosion during relaxation inversion. The well on the inversion ridge requires ca. 1.7 km Jurassic-Early Cretaceous sedimentation followed by Late Cretaceous–Palaeocene erosion during inversion. No well demands thick Cenozoic sedimentation followed by equivalent significant Neogene exhumation. When data are of high quality and models are consistent, the thermal indicator method yields significant results with important tectonic and geodynamic implications.     

Amplitudes of long-period PcP and the core-mantle boundary

The amplitudes of the core reflection PcP are sensitive to the wave velocities and densities in the neighborhood of the core-mantle boundary (CMB). We study the amplitude ratio of the long-period phases PcP and P from two South American deep-focus earthquakes with favorable fault-plane solution, depth and magnitude, as recorded by WWNSS and CSN stations in North America.Comparison is made with long-period PcP/P amplitude ratios, derived from theoretical seismograms for a variety of CMB models. Models from previous studies, which were mainly derived from short-period PcP observations and which are characterized by discrete layers above the CMB, are almost all inconsistent with the long-period data. The data also discriminate against low nonzero S velocities below the CMB. Simple first-order-discontinuity models of the CMB, for instance according to the Jeffreys-Bullen earth model or according to recent models based mainly on free oscillations, explain the data reasonably well.Model improvements are attempted by varying the P-velocity gradient above the CMB. The best amplitude fit is obtained for a rather strong decrease in P velocity with depth in this zone which, however, gives no acceptable traveltime fit for PcP. The scatter in body-wave amplitudes is considerable even for long-period waves and may prevent the correct assessment of that part of the amplitude variation of a phase with distance that is due to the variation of velocities and densities with depth alone.     

无人机航摄生成DEM的高程点快速提取算法

无人机航空摄影技术在近年来得到了迅速的发展,无人机具有起降方便,分辨率高,响应速度快的特点,在抢险救灾,地质灾害监测等方面发挥了重要作用。无人机航空摄影生成的地形图中的高程点提取是地形图制作的重要步骤,本文提出了一种自适应的地形图高程点提取算法,相对于传统的算法,具有精确度高,计算简单,实用性强等特点。该算法的基础是数学形态学中的图像膨胀算法。本文将此算法用于陕西省丹凤县和紫阳县的无人机航摄生成的地形图中,提取了符合要求的高程点。结果表明,提取的高程点完全满足了地形图的要求,说明了该算法的准确性和实用性。     

Biodiversity and invasibility: Distribution patterns of invasive plant species in the Himalayas,Nepal

Invasive plant species are exerting a serious threat to biological diversity in many regions of the world. To understand plant invasions this study aims to test which of the two plant invasiveness hypotheses; ‘low native diversity' vs. ‘high native diversity', is supported by the regional distribution patterns of invasive plant species in the Himalayas,Nepal. This study is based on data retrieved from published literatures and herbarium specimens. The relationship between invasive plant species distribution patterns and that of native plant species is elucidated by scatter plots, as well as by generalized linear models. The native plant species and invasive plant species have similar distribution patterns and the maximum number of invasive plant species is found in the same altitudinal range where the highest richness for native tree species is found. There is a clear trend of higher invasive plant richness in regions where native tree species richness is relatively high.Consequently, the native plant richness is highest in the central phytogeographic region, followed by the eastern and the western regions, respectively. The invasive plant species also follows a similar trend.Additionally, the invasive plant species richness was positively correlated with anthropogenic factors such as human population density and the number of visiting tourists. This study supports the hypothesis that ‘high native diversity' supports or facilitates invasive plant species. Further, it indicates that nativeand invasive plant species may require similar natural conditions, but that the invasive plant species seem more dependent and influenced by anthropogenic disturbance factors.     

II型超新星瞬发爆炸模型的对流不稳定性

本文研究ＩＩ型超新星瞬发爆炸模型中的铁星核在坍缩、反弹和激波传播过程中的对流不稳定性．发现在铁星核内区出现中子指状对流,外区出现Ｓｃｈｗａｒｚｓｃｈｉｌｄ对流,而在声速点和中微子俘陷球之间的过渡区出现Ｌｅｄｏｕｘ对流．在０．７４－０．９１Ｍ间的区域是对流不稳定的活跃区域．     

蒙阴县苏家沟科马提岩

苏家沟科马提岩呈透镜状残留体赋存于早元古代二长花岗岩中,主要由蛇纹石化橄榄科马提岩、透闪石岩、透闪片岩、阳起透闪片岩、绿泥透闪片岩、黑云阳起片岩等组成,具典型的鬣刺结构及变余鬣刺结构。该科马提岩的岩石学、岩石化学及结构特征与世界典型地区科马提岩极为相似,属橄榄科马提岩。     

紫金山铜金矿黄铁矿热电性特征及其地质意义

紫金山铜金矿床是高硫化型浅成热液矿床。本文系统地研究了该矿床黄铁矿的热电性特征,探讨了其与成矿温度、成矿阶段、矿体规模等方面的关系,并应用矿物学填图法对该区的深部找矿远景进行了预测。研究结果表明,该矿床的形成温度集中在80~100℃、240~350℃,属中低温矿床;黄铁矿热电性的热电导型以N型为主,总含量达86.15%,热电系数均值为-168.07μV/℃,在时间和空间上,黄铁矿的热电系数(高负值—低负值—高负值)和N型出现率(高—低—高)都具有韵律变化,从成矿前期到成矿期,黄铁矿P型导电类型的出现率增大,且出现N-P混合型;黄铁矿热电系数分散程度较大,黄铁矿的成矿环境不稳定;矿体的相对埋深表明矿体的变化梯度较大,其产出不稳定,从NW轴向上看,矿体的平均剥蚀百分比数值和相对埋深的绝对值呈现韵律变化,由高到低再到高,由此可以推测,在2号与4号勘探线之间-230m以下可能有富矿体的存在。     

电感耦合等离子体质谱法测定岩石样品中的锆铌铪钽两种预处理方法的比较

研究了微波消解酸溶和过氧化钠碱熔两种测定岩石样品中锆、铌、铪、钽前处理方法,利用电感耦合等离子体质谱法进行测定。对所选用不同种类的岩石国家标准物质样品进行了条件实验,结果表明:采用过氧化钠碱熔法处理岩石样品后,锆、铌、铪、钽的测量值准确度高,且相对标准偏差(RSD,n=10)小于6%,该方法更适用于岩石样品中锆、铌、铪、钽的测定。     

超声提取-固相萃取小柱净化-气相色谱法测定土壤中14种有机氯农药

对土壤中14种有机氯农药的超声提取技术和磺化、固相萃取小柱两种净化方法进行系统研究。结果表明,超声提取节省提取时间,提高分析效率;磺化法和固相萃取小柱法都有净化作用,但磺化法使样品中的艾氏剂、狄氏剂和异狄氏剂全部损失;固相萃取小柱净化当丙酮-正己烷淋洗液体积比为1∶9、淋洗液收集8 mL时回收率>90%,干扰最小。方法检出限为0.63~2.59μg/kg,精密度(RSD,n=7)为1.17%~14.66%,基体加标平均回收率为82.78%~106.94%。方法用于生态地球化学调查评价批量土壤样品的实际分析,检测结果满足评价工作需要。