4D analogue modelling of transtensional pull-apart basins   总被引：3，自引：0，他引：3  

Jonathan E. Wu  Ken McClay  Paul Whitehouse  Tim Dooley 《Marine and Petroleum Geology》2009,26(8):1608-1623

Scaled sandbox models were used to investigate the 4D evolution of pull-apart basins formed above underlapping releasing stepovers in both pure strike-slip and transtensional basement fault systems. Serial sectioning and 3D volume reconstruction permitted analysis of the full 3D fault geometries. Results show that very different pull-apart basins are developed in transtension compared to pure strike-slip. Both types of models produced elongate, sigmoidal to rhomboidal pull-apart systems, but the transtensional pull-apart basins were significantly wider and uniquely developed a basin margin of en-echelon oblique-extensional faults. Dual, opposing depocentres formed in the transtensional model whereas a single, central depocentre formed in pure strike-slip. In transtension, a distinct narrow graben system formed above the principal displacement zones (PDZs). Cross-basin fault systems that linked the offset PDZs formed earlier in the transtensional models.Sequential model runs to higher PDZ displacements allowed the progressive evolution of the fault systems to be evaluated. In cross-section, transtensional pull-aparts initiated as asymmetric grabens bounded by planar oblique-extensional faults. With increasing displacement on the PDZs, basin subsidence caused these faults to become concave-upwards and lower in dip angle due to fault block collapse towards the interior of the basin. In addition, strain partitioning caused fault slip to become either predominantly extensional or strike-slip. The models compare closely with the geometries of natural pull-apart basins including the southern Dead Sea fault system and the Vienna Basin, Austria.  相似文献   

Estimation of Interstitial Velocity Using a Direct Drive High-Resolution Passive Profiler     

Haley A. Schneider  W. Andrew Jackson  Ken Rainwater  Danny Reible  Stephen Morse  Paul B. Hatzinger  Uriel Garza-Rubalcava 《Ground water》2019,57(6):915-924

The fate and transport of groundwater contaminants depends partially on groundwater velocity, which can vary appreciably in highly stratified aquifers. A high-resolution passive profiler (HRPP) was developed to evaluate groundwater velocity, contaminant concentrations, and microbial community structure at ∼20 cm vertical depth resolution in shallow heterogeneous aquifers. The objective of this study was to use mass transfer of bromide (Br⁻), a conservative tracer released from cells in the HRPP, to estimate interstitial velocity. Laboratory experiments were conducted to empirically relate velocity and the mass transfer coefficient of Br⁻ based on the relative loss of Br⁻ from HRPP cells. Laboratory-scale HRPPs were deployed in flow boxes containing saturated soils with differing porosities, and the mass transfer coefficient of Br⁻ was measured at multiple interstitial velocities (0 to 100 cm/day). A two-dimensional (2D) quasi-steady-state model was used to relate velocity to mass transfer of Br⁻ for a range of soil porosities (0.2–0.5). The laboratory data indicate that the mass transfer coefficient of Br⁻, which was directly—but non-linearly—related to velocity, can be determined with a single 3-week deployment of the HRPP. The mass transfer coefficient was relatively unaffected by sampler orientation, length of deployment time, or porosity. The model closely simulated the experimental results. The data suggest that the HRPP will be applicable for estimating groundwater velocity ranging from 1 to 100 cm/day in the field at a minimum depth resolution of 10 cm, depending on sampler design.  相似文献   

一种新型潜浮式深海地震仪的设计与试验     

孟肯  秦华伟  朱心科  侯斐 《热带海洋学报》2020,39(3):49-56

鉴于国内外海洋地震台网的缺乏, 本文介绍了一种面向全球海域应用的漂浮式海底地震接收系统(mobile earthquake recording in marine areas by independent divers, MERMAID)。针对潜浮式地震仪MERMAID浮标的研发过程, 建立了浮标的总体设计要求与典型工作循环流程, 设计了液压式浮力调节系统、机械结构等, 并对比分析了不同转速及负浮力下潜过程, 最后进行了实验室压力检测和千岛湖湖试。试验结果表明, 该浮标能在15MPa压力下保持良好的密封性与稳定性, 利用水听器可以有效地采集到天然地震纵波(P波), 同时计算各模块单个周期的能耗, 以验证设计指标。  相似文献   

Basin-scale distribution of NH<Subscript>4</Subscript><Superscript>+</Superscript> and NO<Subscript>2</Subscript><Superscript>−</Superscript> in the Pacific Ocean     

Sayaka Yasunaka  Yukihiro Nojiri  Taketo Hashioka  Chisato Yoshikawa  Taketoshi Kodama  Shin-ichiro Nakaoka  Sanae Chiba  Fuminori Hashihama  Masahide Wakita  Ken Furuya  Daisuke Sasano  Akihiko Murata  Hiroshi Uchida  Michio Aoyama 《Journal of Oceanography》2018,74(1):1-11

We used more than 25,000 nutrient samples to elucidate for the first time basin-scale distributions and seasonal changes of surface ammonium (NH₄ ⁺) and nitrite (NO₂ ^?) concentrations in the Pacific Ocean. The highest NH₄ ⁺, NO₂ ^?, and nitrate (NO₃ ^?) concentrations were observed north of 40°N, in the coastal upwelling region off the coast of Mexico, and in the Tasman Sea. NH₄ ⁺ concentrations were elevated during May–October in the western subarctic North Pacific, May–December in the eastern subarctic North Pacific, and June–September in the subtropical South Pacific. NO₂ ^? concentrations were highest in winter in both hemispheres. The seasonal cycle of NH₄ ⁺ was synchronous with NO₂ ^?, NO₃ ^?, and satellite chlorophyll a concentrations in the western subtropical South Pacific, whereas it was synchronous with chlorophyll-a but out of phase with NO₂ ^? and NO₃ ^? in the subarctic regions.  相似文献   

efa^{②对Con-A诱导的小鼠肝脏损伤模型的保护作用研究}          下载免费PDF全文

彭求贤  赖冬妮  翁建霖 《应用海洋学学报》2018,34(10):158-160

目的：探讨efa^{②对刀豆蛋白（con-A）诱导的自身免疫性肝炎小鼠模型的保护作用及其可能的作用机制。方法：将50只昆明种小鼠随机分为正常对照组、con-A自身免疫性肝炎模型组及样品efa②高（0.04mL/20g）、中（0.02mL/20g）、低（0.01mL/20g）剂量组,分别给予0.9%氯化钠注射液或相应浓度的efa②样品灌胃,每天1次,连续7d。本次灌胃结束禁食1晚后,尾静脉注射Con-A,断头取血测生化指标,并取肝右叶组织作病理切片,对肝脏组织中的CYP5A1、CYP2E1和CYP3A进行蛋白分析。结果：efa②能使自身免疫性肝炎模型小鼠血清中IL-10升高以及IFN-γ、TNF-α、PGE1活性降低。结论：efa②具有调节肝炎模型小鼠血清各细胞因子及ALT的水平,并显著改善肝脏组织病理变化的作用,其保护机制可能与CYP2E1相关。  相似文献}   

Olin J Eggen 1919–1998     

Ken Freeman 《Astronomy& Geophysics》2000,41(1):1.36-1.36

  相似文献   

High-Reflectivity Coatings for a Vacuum Ultraviolet Spectropolarimeter     

Noriyuki Narukage  Masahito Kubo  Ryohko Ishikawa  Shin-nosuke Ishikawa  Yukio Katsukawa  Toshihiko Kobiki  Gabriel Giono  Ryouhei Kano  Takamasa Bando  Saku Tsuneta  Frédéric Auchère  Ken Kobayashi  Amy Winebarger  Jim McCandless  Jianrong Chen  Joanne Choi 《Solar physics》2017,292(3):40

Precise polarization measurements in the vacuum ultraviolet (VUV) region are expected to be a new tool for inferring the magnetic fields in the upper atmosphere of the Sun. High-reflectivity coatings are key elements to achieving high-throughput optics for precise polarization measurements. We fabricated three types of high-reflectivity coatings for a solar spectropolarimeter in the hydrogen Lyman-\(\upalpha \) (Ly\(\upalpha \); 121.567 nm) region and evaluated their performance. The first high-reflectivity mirror coating offers a reflectivity of more than 80 % in Ly\(\upalpha \) optics. The second is a reflective narrow-band filter coating that has a peak reflectivity of 57 % in Ly\(\upalpha \), whereas its reflectivity in the visible light range is lower than 1/10 of the peak reflectivity (\(\sim 5~\%\) on average). This coating can be used to easily realize a visible light rejection system, which is indispensable for a solar telescope, while maintaining high throughput in the Ly\(\upalpha \) line. The third is a high-efficiency reflective polarizing coating that almost exclusively reflects an s-polarized beam at its Brewster angle of 68° with a reflectivity of 55 %. This coating achieves both high polarizing power and high throughput. These coatings contributed to the high-throughput solar VUV spectropolarimeter called the Chromospheric Lyman-Alpha SpectroPolarimeter (CLASP), which was launched on 3 September, 2015.  相似文献   

The role of syntectonic sedimentation in the evolution of doubly vergent thrust wedges and foreland folds     

Leo Duerto  Ken McClay 《Marine and Petroleum Geology》2009

This paper shows the evolution of time-constrained two-dimensional scaled analogue models of doubly vergent thrust systems in the presence of syntectonic sedimentation. Two sets of experiments were considered: (1) the addition of a syntectonic layer composed of a polymer and overlying sand in the prowedge; and (2) the addition to the previous condition of a progradational sedimentary load. Results from the first set of experiments indicate that the foreland fold-and-thrust belt has a strong relationship with the competence of the syntectonic layers. When the competence is low, the deformation produces tight asymmetric detachment-folds. As the competence increases, the fold-and-thrust belt shows break-trough folds with longer and better defined foreland-vergence. Results from the second set of experiments indicate that structural vergence is determined by the sense of progradation of the syntectonic layers, and in the case of strong aggradation at the prowedge, extension and reactive diapirism form contemporaneously with the contraction. Three end-members are proposed for mountain front thrust systems formed in the presence of syntectonic polymer and sand sedimentation: (1) outcropping fold-and-thrust belt sequence, in the case of no syntectonic sedimentation; (2) long displacement blind-thrust sheets, in the case of under-filled basins and (3) short displacement blind-thrust sheets, in the case of over-filled basins. All results indicate that ductile units at the base of syntectonic layers increase the displacement of the underlying frontal thrusts at the prowedge, and reduce the critical taper. Results also indicate that at very high sedimentary rates and hyper-critical taper conditions the prowedge collapses. Conclusions drawn from this research may be applied as an analogue to foreland evolution and to evaluate hydrocarbon generation, migration, and entrapment in thrust belts in areas where seismic imaging is generally poor.  相似文献   

Biomarker records from core GH02-1030 off Tokachi in the northwestern Pacific over the last 23,000 years: Environmental changes during the last deglaciation     

Masaki Inagaki  Masanobu Yamamoto  Yaeko Igarashi  Ken Ikehara 《Journal of Oceanography》2009,65(6):847-858

We investigated marine and terrestrial environmental changes at the northern Japan margin in the northwestern Pacific during the last 23,000 years by analyzing biomarkers (alkenones, long-chain n-alkanes, long-chain n-fatty acids, and lignin-derived materials) in Core GH02-1030. The U ₃₇^K′-derived temperature in the last glacial maximum (LGM) centered at 21 ka was ∼10°C, which was 2°C lower than the core-top temperature (∼12°C). This small temperature drop does not agree with pollen evidence of a large air temperature drop (more than 4°C) in the Tokachi area. This disagreement might be attributed to a bias of U ₃₇^K′-derived temperature within 2.5°C by a seasonal shift in alkenone production. The U ₃₇^K′-derived temperature was significantly low during the last deglaciation. Because this cooling was significant in the Kuroshio-Oyashio transition zone, the temperature drops are attributable to the southward displacement of the Kuroshio-Oyashio boundary. Abundant lignin-derived materials, long-chain n-alkanes and long-chain n-fatty acids indicate a higher contribution of terrigenous organic matter from 17 to 12 ka. This phenomenon might have resulted from an enhanced coastal erosion of terrestrial soils due to marine transgression and/or an efficient inflow of higher plant debris to river waters from 17 to 12 ka.  相似文献   

A dimension-independent extrusion algorithm using generalised maps     

Ken Arroyo Ohori  Hugo Ledoux  Jantien Stoter 《International journal of geographical information science》2013,27(7):1166-1186

One solution to the integration of additional characteristics, for example, time and scale, into GIS data sets is to model them as extra geometric dimensions perpendicular to the spatial ones, creating a higher-dimensional model. While this approach has been previously described and advocated, it is scarcely used in practice because of a lack of high-level construction algorithms and accompanying implementations. We present in this paper a dimension-independent extrusion algorithm permitting us to construct from any (n–1)-dimensional linear cell complex represented as a generalised map, an n-dimensional one by assigning to each (n–1)-cell one or more intervals where it exists along the nth dimension. We have implemented the algorithm in C++11 using CGAL, made the source code publicly available and tested it in experiments using real-world 2D GIS data sets which were extruded to construct up to 5D models.  相似文献