天津市滨海新区芦苇湿地恢复适宜性评价     

许妍  许自舟  梁斌  洛昊  鲍晨光  梁雅惠  马明辉 《海洋科学》2016,40(3):101-107

利用综合评价模型,结合地理信息系统技术的空间分析功能,以土地利用、土壤类型、坡度、降雨量和人类干扰活动作为评价因子,对天津滨海新区芦苇湿地恢复进行了适宜性评价。结果表明,较适宜开展湿地恢复的比例为21.46%,一般适宜比例为21.87%,不适宜比例占56.68%,其中较适宜湿地恢复的区域集中分布在北大港湿地自然保护区周边、独流减河下游、北塘入海口以及沿海滩涂,海河流域两侧也有零星分布。在适宜性评价基础上,对未来芦苇湿地恢复与建设的重点区域进行了成效预评估,芦苇对TC、TN、TP的年吸收通量约为1.3935×104、0.0258×104、0.0017×104t,能有效地减少入海排污压力和污染物对近岸海域环境质量的影响。研究结论可为天津湿地治理与生态恢复、土地利用结构调整、景观优化等提供理论依据和科学参考。  相似文献   

John Turnbull Thomson,Fellow of the Royal Geographical Society: An early New Zealand geographer          下载免费PDF全文

Michael Roche 《New Zealand geographer》2016,72(1):3-13

John Turnbull Thomson is more known in New Zealand for his work as Chief Surveyor of Otago Province (1856–1876) and first Surveyor General of New Zealand (1877–1879). He was also a Fellow of the Royal Geographical Society of London from 1848 until his death in 1884. Thomson was an important and early self‐declared ‘does’ of geographer in New Zealand, prior to the establishment of university geography in 1937. Thomson's contribution included survey and mapping but he also gave public lectures on geography and contributed to debates about glaciation.  相似文献   

Evaluation of coseismic landslide hazard on the proposed Haast-Hollyford Highway,South Island,New Zealand     

Tom R. Robinson  Tim R. H. Davies  Thomas M. Wilson  Caroline Orchiston  Nicolas Barth 《Georisk: Assessment and Management of Risk for Engineered Systems and Geohazards》2016,10(2):146-163

Coseismic landsliding presents a major hazard to infrastructure in mountains during large earthquakes. This is particularly true for road networks, as historically coseismic landsliding has resulted in road losses larger than those due to ground shaking. Assessing the exposure of current and planned highway links to coseismic landsliding for future earthquake scenarios is therefore vital for disaster risk reduction. This study presents a method to evaluate the exposure of critical infrastructure to landsliding from scenario earthquakes from an underlying quantitative landslide hazard assessment. The method is applied to a proposed new highway link in South Island, New Zealand, for a scenario Alpine Fault earthquake and compared to the current network. Exposure (the likelihood of a network being affected by one or more landslides) is evaluated from a regional-scale coseismic landslide hazard model and assessed on a relative basis from 0 to 1. The results show that the proposed Haast-Hollyford Highway (HHH) would be highly exposed to coseismic landsliding with at least 30–40?km likely to be badly affected (the Simonin Pass route being the worse affected of the two routes). In the current South Island State Highway network, the HHH would be the link most exposed to landsliding and would increase the total network exposure by 50–70% despite increasing the total road length by just 3%. The present work is intended to provide an effective method to assess coseismic landslide hazard of infrastructure in mountains with seismic hazard, and potentially identify mitigation options and critical network segments.  相似文献   

A new record and a new ichnospecies of Arachnostega from the Middle Miocene of Egypt     

Olev Vinn  Ahmed M. El-Sabbagh  Magdy M. El-Hedeny  Mohamed A. Rashwan  Saleh A. Al Farraj 《Proceedings of the Geologists' Association. Geologists' Association》2018,129(6):790-796

The ichnogenus Arachnostega Bertling, 1992 is recorded for the first time from a bioeroded, coral-rich, Middle Miocene limestone bed in the middle Siwa Escarpment Member (Marmarica Formation) at Siwa Oasis, northern Western Desert of Egypt. These burrowing traces are preserved on the surface of a few internal moulds of bivalves and gastropods. Until now, the ichnogenus Arachnostega included a single ichnospecies, A. gastrochaenae Bertling, 1992. In the material studied herein, two ichnospecies are identified, described, illustrated and compared with other, similar traces. One of these is a new ichnospecies of Arachnostega; this is here named A. siwaensis ichnosp. nov. It is distinguished from A. gastrochaenae in the possession of tunnels that usually branch in a V-pattern; intervals of ramification are longest in the main branch and decrease in second- and third-order branches. Arachnostega traces were produced in a warm, low-energy, shallow-marine (<10?m water depth) environment. Polychaetes are the most likely producers of marine Arachnostega, which are commonly occurred in the same studied bed. This new occurrence is significant in extending the known stratigraphical and geographical ranges of Arachnostega into the Middle Miocene of Egypt.  相似文献   

A new tribe of Galerucinae leaf beetle (Insecta: Coleoptera: Chrysomelidae) from the Upper Cretaceous Taimyr amber     

《Cretaceous Research》2018

The new tribe Taimyralticini trib. nov., new genus Taimyraltica gen. nov. and new species Taimyraltica calcarata sp. nov. (Coleoptera: Chrysomelidae: Galerucinae) are described from Upper Cretaceous (Santonian) Taimyr amber of northern Siberia (Yantardakh locality). The new genus shares characters with genera of the tribe Alticini (small size, transverse antebasal groove on pronotum, regular punctate-striate elytra) and the Galerucini (narrow, non-swollen metafemora). A possible apomorphy of the new genus and tribe is a large and acute metatibial spur, erect and oriented transversely to the longitudinal axis of tibia. This character state is unknown in recent and fossil genera of Galerucinae. Early evolution and divergence of leaf beetles are discussed, and a Jurassic and Early Cretaceous subfamily radiation is proposed. Fossil galerucines are reviewed. The oldest Phyllotreta is recorded from the lower Miocene of Izarra (Spain). Our findings show an extreme rarity of Phytophaga in Taimyr amber from Yantardakh. Absence of Phytophaga was recorded earlier at Obeschayuschiy (Santonian-Campanian of the Magadan Region) and compared with their much larger share in Khetana (north of Khabarovsk Krai); we find nearly the same differences between Taimyr amber from Yantardakh and Canadian amber. In Obeschayuschiy this appears due to the Mesophytic character of the flora. It is assumed that the Santonian amber gymnosperm forest of the Khatanga Basin had the same character.  相似文献   

辽宁省沈抚新区区域地壳稳定性评价     

张春山  张树轩  杨为民  孟华君  吕佳进  张田田  吴季寰  郭涵 《地质力学学报》2021,27(3):453-462

在广泛收集资料和野外调查工作的基础上,经综合分析控制和影响区域地壳稳定性的主要因素和内外动力地质的耦合作用,基于ArcGIS平台采用多因素加权叠加分析方法开展了沈抚新区区域地壳稳定性评价研究。评价因素主要选取活动断裂、地震活动性和深部地球物理以及工程岩组、地形地貌与地表地质灾害等共12个影响因子,并依据评价因素的关联性和重要性进行分类赋值,进而建立了区域地壳稳定性评价模型。对沈抚新区的区域地壳稳定性进行了定量化评价。结果表明,沈抚新区以稳定区和次稳定区为主,面积为728.9 km2,占总面积的81.07%,有利于规划和建设。建议在地下工程穿越不稳定区和次不稳定区时,要采取必要的工程措施,确保基础和边坡的稳定性。规划的地铁9号线主要穿越次不稳定区和次稳定区。施工带在埋深15~25 m之间,该段地层主要为卵砾石堆积层、泥包砾堆积层与变质片麻岩强风化带及其交接部位,施工带处于地下水浸没带或变动带,其支护比较困难,建议尽早确定合理的施工方案,保障施工顺利和安全,此外还需要采取一定降水防腐措施。   相似文献   

High‐ to ultrahigh‐temperature metamorphism in the lower crust: An example resulting from Hikurangi Plateau collision and slab rollback in New Zealand          下载免费PDF全文

Jean‐Baptiste Jacob  James M. Scott  Rose E. Turnbull  Matthew S. Tarling  Matthew W. Sagar 《Journal of Metamorphic Geology》2017,35(8):831-853

Lower crustal xenoliths erupted from an intraplate diatreme reveal that a portion of the New Zealand Gondwana margin experienced high‐temperature (HT) to ultrahigh‐temperature (UHT) granulite facies metamorphism just after flat slab subduction ceased at c. 110–105 Ma. P–T calculations for garnet–orthopyroxene‐bearing felsic granulite xenoliths indicate equilibration at ~815 to 910°C and 0.7 to 0.8 GPa, with garnet‐bearing mafic granulite xenoliths yielding at least 900°C. Supporting evidence for the attainment of HT and UHT conditions in felsic granulite comes from re‐integration of exsolution in feldspar (~900–950°C at 0.8 GPa), Ti‐in‐zircon thermometry on Y‐depleted overgrowths on detrital zircon grains (932°C ± 24°C at aTiO₂ = 0.8 ± 0.2), and correlation of observed assemblages and mineral compositions with thermodynamic modelling results (≥850°C at 0.7 to 0.8 GPa). The thin zircon overgrowths, which were mainly targeted by drilling through the cores of grains, yield a U–Pb pooled age of 91.7 ± 2.0 Ma. The cause of Late Cretaceous HT‐UHT metamorphism on the Zealandia Gondwana margin is attributed to collision and partial subduction of the buoyant oceanic Hikurangi Plateau in the Early Cretaceous. The halt of subduction caused the fore‐running shallowly dipping slab to rollback towards the trench position and permitted the upper mantle to rapidly increase the geothermal gradient through the base of the extending (former) accretionary prism. This sequence of events provides a mechanism for achieving regional HT–UHT conditions in the lower crust with little or no sign of this event at the surface.  相似文献   

The anatomy of a disaster, an overview of Hurricane Katrina and New Orleans     

Lewis E. Link 《Ocean Engineering》2010,37(1):4-12

Hurricane Katrina created the one of the worst natural disaster in the history of the United States, resulting in over 1600 fatalities and $30B in direct economic losses in southern Louisiana. The Louisiana and Mississippi coastlines experienced the highest surge level recorded in North America and Katrina-generated waves in the Gulf of Mexico that equaled the highest previously measured by NOAA buoys. What happened in New Orleans epitomizes the risk of living below sea level in a coastal city, depending on structures that were the result of considerable compromise and piecemeal funding and construction. The Interagency Performance Evaluation Task Force was established to examine the performance of the New Orleans and southeast Louisiana hurricane protection system and provide real-time input to the repairs and rebuilding of the system. In addition to this atypical just-in-time forensic analysis, the task force examined the risk of living in New Orleans prior to and following the repairs to the hurricane protection system. Much of the forensic analysis depended on modeling and simulation of hurricane surge and waves. With virtually all measurement instruments swept away by Katrina, only models and high-water marks were available to recreate the conditions that the structures experienced during the storm. Because of the complexities of the region and the processes involved, simulation of hurricane surge and waves required many fresh ideas and new approaches and these topics, along with new concepts for future planning and design, are the focus of this special issue. Yet, the need to influence the repair and rebuilding of the damaged structures prior to the next hurricane season (roughly 9 months) dictated using existing computational tools that were ready to go. The same modeling and simulation approach was put to work to define the surge and wave hazard New Orleans faces for the future. To put this important body of work in context, this paper provides a broad overview of the entire scope of work of the task force and summarizes its principal findings.  相似文献   

Private rights,public benefits: Industry-driven seabed protection     

Jeremy Helson  Stefan Leslie  George Clement  Richard Wells  Ray Wood 《Marine Policy》2010

New Zealand has a large exclusive economic zone (EEZ) that contains a variety of marine habitats and commercially-important species. The commercial fishing industry operating within New Zealand's EEZ is of significant value to the economy and fisheries resources are managed through the extensive use of Individual Transferable Quotas (ITQs). One of the benefits of ITQs has been to better align some of the private incentives of quota owners with the public interest. These incentives contributed to an initiative proposed by the fishing industry to close large areas of New Zealand's EEZ to protect the seabed from trawling. These closed areas are termed benthic protection areas (BPAs) and protect the benthic biodiversity of about 1.1 million square kilometres of seabed—approximately 30% of New Zealand's EEZ. A significant proportion of New Zealand's known seamounts and active hydrothermal vents are protected by these closed areas. We describe and discuss the criteria used to select BPAs and some of the criticism of this marine protection initiative. We argue that the assignment of strong property rights in fishing resources was an important precondition to an industry initiative that has a significant public benefit. Where private and public interests are well aligned, government can adopt an enabling and facilitation role, ceding direct control of processes in order to get the results the align with the public interest.  相似文献   

Subduction and back-arc activity at the Hikurangi convergent Margin,New Zealand     

Euan G. C. Smith  Tim Stern  Martin Reyners 《Pure and Applied Geophysics》1989,129(1-2):203-231

The Hikurangi Margin is a region of oblique subduction with northwest-dipping intermediate depth seismicity extending southwest from the Kermadec system to about 42°S. The current episode of subduction is at least 16–20 Ma old. The plate convergence rate varies along the margin from about 60 mm/a at the south end of the Kermadec Trench to about 45 mm/a at 42°S. The age of the Pacific lithosphere adjacent to the Hikurangi Trench is not known.The margin divides at about latitude 39°S into two quite dissimilar parts. The northern part has experienced andesitic volcanism for about 18 Ma, and back-arc extension in the last 4 Ma that has produced a back-arc basin onshore with high heaflow, thin crust and low upper-mantle seismic velocities. The extension appears to have arisen from a seawards migration of the Hikurangi Trench north of 39°S. Here the plate interface is thought to be currently uncoupled, as geodetic data indicate extension of the fore-arc basin, and historic earthquakes have not exceededM _s=7.South of 39°S there is no volcanism and a back-arc basin has been produced by downward flexure of the lithosphere due to strong coupling with the subducting plate. Heatflow in the basin is normal. Evidence for strong coupling comes from historic earthquakes of up to aboutM _s=8 and high rates of uplift on the southeast coast of the North Island.The reason for this division of the margin is not known but may be related to an inferred increase, from northeast to southwest, in the buoyancy of the Pacific lithosphere.  相似文献