Assessing tectonic and climatic causal mechanisms in foreland‐basin stratal architecture: insights from the Alborz Mountains,northern Iran

The southern foreland basin of the Alborz Mountains of northern Iran is characterized by an approximately 7.3‐km‐thick sequence of Miocene sedimentary rocks, constituting three basin‐wde coarsening‐upward units spanning a period of 10⁶ years. We assess available magnetostratigraphy, paleoclimatic reconstructions, stratal architecture, records of depositional environments, and sediment‐provenance data to characterize the relationships between tectonically‐generated accommodation space (A) and sediment supply (S). Our analysis allows an inversion of the stratigraphy for particular forcing mechanisms, documenting causal relationships, and providing a basis to decipher the relative contributions of tectonics and climate (inferred changes in precipitation) in controlling sediment supply to the foreland basin. Specifically, A/S > 1, typical of each basal unit (17.5–16.0, 13.8–13.1 and 10.3–9.6 Ma), is associated with sharp facies retrogradation and reflects substantial tectonic subsidence. Within these time intervals, arid climatic conditions, changes in sediment provenance, and accelerated exhumation in the orogen suggest that sediment supply was most likely driven by high uplift rates. Conversely, A/S < 1 (13.8 and 13.8–11 Ma, units 1, and 2) reflects facies progradation during a sharp decline in tectonic subsidence caused by localized intra‐basinal uplift. During these time intervals, climate continued to be arid and exhumation active, suggesting that sediment supply was again controlled by tectonics. A/S < 1, at 11–10.3 Ma and 9‐6–7.6 Ma (and possibly 6.2; top of units 2 and 3), is also associated with two episodes of extensive progradation, but during wetter phases. The first episode appears to have been linked to a pulse in sediment supply driven by an increase in precipitation. The second episode reflects a balance between a climatically‐induced increase in sediment supply and a reduction of subsidence through the incorporation of the proximal foreland into the orogenic wedge. This in turn caused an expansion of the catchment and a consequent further increase in sediment supply. Copyright © 2013 John Wiley & Sons, Ltd.     

基于共享数据平台的云南漾濞和青海玛多地震应急物资配置分析

灾后信息缺失易导致应急决策失效和调整困难,针对2021年5月下旬云南大理州漾濞县及青海果洛州玛多县分别发生6.4级和7.5级地震,本文设计了一种基于共享数据平台实时信息的灾后应急物资配置方法。该方法主要利用基于地震台网发布灾害信息确定灾区范围,基于人口分布数据估测需求与供给缺口,并通过高德开放平台接口获取交通态势确定可供通行的路网与实时最优运输路径,利用这些实时信息做出震后物资分配调度快速决策。通过漾濞和玛多地震案例分析结果显示:通过震后第一时间数据,可快速处理收集数据并进行供需评估与物资调度辅助决策。当灾区存在供需缺口,利用相邻县物资可维系震后短期内物资需求;对于物资运输,实时更新的信息可为其选择最佳路线。本方法为震后应急物资动态配置中决策实时更新与调整提供依据,为日后地震应急响应提供参考。     

西部水资源研究 西部大开发与水资源的合理利用

水资源短缺已成为西部开发和当地社会经济可持续发展的制约因素。如何合理利用水资源、增加水资源的有效供给已成为当前亟待解决的问题。本文根据该区水资源的特点社会经济发展现状，在分析水资源短缺的原因、存在问题的基础上，提出了调整产业结构、发展高效节水产业，推广节水技术，加强水资源利用的综合管理，应用地球物理方法勘查地下水资源、采取工程措施增加大气降水等措施以缓解水资源短缺的现状。     

旱作物灌溉用水预测公式

从土壤湿润层水量平衡出发,推导出旱作物灌溉用水预测公式,利用历史实测灌溉用水及同期降雨资料率定有关参数,根据降雨预报资料预测灌溉用水量。方法简便,适用于种植结构不明的灌区,特别是数个灌区构成的灌溉区域。     

两种气候变化情景下中国未来的粮食供给

全球温室气体排放导致的全球温度的上升一直是国际社会关注的重点问题之一。利用IPCC（政府间气候变化专门委员会）SRES（排放情景特别报告）的A2（中-高）和B2（中-低）温室气体排放情景,结合区域气候模式PRECIS和CERES作物模型模拟和分析了未来不同的温室气体排放情景下,中国未来2020年、2050年和2080年各个时段粮食的供需情景,并结合未来社会经济的发展分析了气候变化对未来粮食供求的影响,探讨了不同的气候变化程度对未来中国粮食供应的影响。结果表明：如果不考虑CO2的肥效作用,未来我国三种主要粮食作物（小麦、水稻和玉米）均以减产为主,灌溉可以部分地减少减产幅度,如果单考虑CO2的肥效作用,三种作物的产量变化以增产为主。若保持959／6的粮食自给率,人口按照SRESA2和B2情景增长,到2030年的技术进步可使粮食年单产递增0．79／6以上,维持目前的种植比例和种植面积,B2情景下,气候变化对我国的粮食安全问题将不会构成威胁,而A2情景下,气候变化将会对我国可持续发展的粮食安全造成威胁。     

Searching for market-based sustainability pathways: Challenges and opportunities for seafood certification programs in Japan

Over the past two decades, there has been a proliferation of consumer-facing, market-based initiatives for marine conservation—most notably in seafood eco-labels and sustainability certifications. Yet, despite the growing recognition of these initiatives by consumers and retailers in North America and Europe and the (subsequent) acceptance of their role in seafood distribution by fisheries and fish marketing industries around the world, seafood certification programs have thus far made little progress in Japan. Here, the evolution of the three seafood eco-label and certification programs in Japan is examined and insights into the ongoing challenges they face in terms of the domestic supply chain network, consumer preference and their social-cultural attitude toward sustainability are provided. Despite an initial lack of success, seafood certification programs in Japan can be useful in enhancing consumer awareness for fisheries resource conservation and identifying Japanese domestic small-scale fisheries that are already engaged in sustainable fishing practices. A possible pathway for developing an eco-certification program suitable for the Japanese seafood market is provided through integration of environmental and cultural sustainability under the existing certification framework.     

徐家围子断陷安达凹陷火石岭组天然气成藏条件分析

DS28井的勘探研究表明徐家围子断陷火石岭组具有良好的勘探前景.笔者通过对岩芯地化测试、铸体薄片、孔隙度测试等资料的分析,探究安达凹陷火石岭组天然气的气源条件、储层特征、盖层条件和成藏模式,以期深入认识松辽盆地北部火石岭组天然气富集规律,指出有利勘探区带和勘探方向.研究表明,安达凹陷火石岭组具备天然气藏形成的基本地质条...     

Alternate bar dynamics in response to increases and decreases of sediment supply

Gravel‐bed rivers can accommodate changes in sediment supply by adjusting their bed topography and grain size in both the downstream and cross‐stream directions. Under high supply aggradational conditions, this can result in spatially non‐uniform stratigraphic patterns, and the morphodynamic influence of heterogeneous stratigraphy during subsequent degradational periods is poorly understood and has not been studied through physical modelling. A flume experiment was conducted to analyse channel response where alternate bars were developed in a gravel–sand mixture under constant discharge and sediment supply before two supply increases led to the development of heterogeneous stratigraphy beneath alternate bars. The supply was then reduced back to the initial supply rate, causing degradation through that self‐formed stratigraphy. Stratigraphic samples were collected, and the bed topography and flow depth were measured frequently, which were used with a two‐dimensional hydrodynamic model to characterize flow conditions. Migrating alternate bars stabilized during the first equilibrium phase, creating bed surface sorting patterns of coarse bar tops and fine pools. During the first supply increase, the bars remained stable as the pools aggraded. During the second supply increase, the pools aggraded further, causing the boundary shear stress over the bar tops to increase until the bars gained the capacity to migrate and eventually stabilize in new locations. As aggradation occurred, the original sediment sorting patterns were preserved in the subsurface. During the degradational phase, the pools experienced incision and the bars eroded laterally, but this lateral erosion ceased when coarse sediment previously deposited during the bar‐building phase became exposed. The results suggest that if a sediment supply increase is capable of filling the pools, it can cause stable bars to migrate and the bed to be reworked. These findings also show that heterogeneous stratigraphy can play an important role in determining whether bars persist or disappear after a sediment supply reduction.     

深圳市土地供给与经济增长关系研究

利用连续的动态资料，对深圳土地供给稀缺性、土地供给与经济发展的相关性、土地利用弹性系数、土地供给对经济增长贡献率及其变化进行了定量分析。结果表明，深圳建设用地的快速扩张支撑了经济总量和城市建设的高速发展；经济增长与土地供给呈现一致波动性，并表现出滞后性；土地投入对经济增长的贡献具有“隐性贡献”的特点。     

地电阻率观测系统稳流电源技术的发展

详尽地分析了地电阻率观测系统的供电电源的发展过程。对几种电源的技术指标和性能作出了评价。在对几种电源的若干技术问题进行了分析和讨论后，指出对地电阻率观测系统的稳流电源的设计应用高频开关电源技术。介绍了作设计的主电路图。