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851.
In the context of the current review of New Zealand's National Certificate of Educational Achievement (NCEA), the paper reflects on the nature and relevance of geography in education, life and work. The context of school geography programmes is critically examined, and a checklist of points for further consideration and action is presented. 相似文献
852.
A new species of wasp from the Laiyang Formation in Shandong, China is described and named Cretaproscolia asiatica sp. nov. It is the second record of the genus Cretaproscolia Rasnitsyn and Martínez-Delclòs, 1999, and extends the distribution of the genus from the Lower Cretaceous of South America into the upper Mesozoic of East Asia. The diagnosis of Cretaproscolia is emended based on the new material. 相似文献
853.
A new species, Shoushida infera sp. nov. and a new genus with a new species, Stelepelecinus longus gen. et sp. nov., both in Pelecinidae, are described and illustrated. All specimens were collected from the Lower Cretaceous of Yixian Formation, Jehol Biota at Huangbanjigou, Beipiao City, western Liaoning Province, China. The forewing of Shoushida infera sp. nov. has a rudimentary “X” pattern, formed by veins of Rs, Rs1, Rs2 and 2r-rs, which is similar to but slightly different from that of Shoushida regilla Liu, Shih et Ren, 2009. Consistent with the phylogeny of Pelecinidae reported by Shih et al., 2010, this new species and S. regilla represent a transition between basal and crown pelecinids and the rudimentary “X” pattern evolved later to a more developed and robust “X” pattern in more derived pelecinids. In addition, the long petiole of the basalmost segment of metasoma, present in the male Stelepelecinus longus gen. et sp. nov., is documented for the first time, suggesting a likely Early Cretaceous origination of metasomal evolution leading to the thin and long petiole structure in the extant male Pelecinus thoracicus. We proposed two probable pathways of the transformation of the pelecinid male metasoma from the most plesiomorphic state to the more apomorphic states. 相似文献
854.
Permian–Triassic fore-arc basin terranes are exposed in New Zealand, but their original positions and tectonic configurations along the eastern Gondwanan margin are not fully understood. To better constrain late Paleozoic and Mesozoic reconstructions, we investigated the provenance of Permian–Triassic marine sandstone units from the Dun Mountain-Maitai Terrane (Maitai Group) and the Kaka Point Structural Belt (Willsher Group). The recognition of abundant volcanic lithic fragments in the sandstone samples, combined with the pattern of detrital zircon ages (unimodal to bimodal 280–240 Ma age distribution), demonstrate that the upper Permian to Middle Triassic volcaniclastic successions were derived from a proximal arc source. The detrital zircon age spectra match magmatic pulses in the adjacent Tuhua Intrusives (Median Batholith), a conclusion similar to that recently proposed for the Brook Street Terrane (Grampian Formation) and Murihiku Terrane (Murihiku Supergroup). Trace-element data from the dated zircon grains provide further evidence for a Median Batholith source and cross-terrane provenance links. The data indicate that 275–230 Ma zircon grains from the Maitai Group, Willsher Group, and Murihiku Supergroup were derived from a common magmatic source, and that the late Permian Longwood Suite (261–252 Ma) in the Median Batholith was a source region for these terranes. Based on the cross-terrane provenance links, we suggest that the Brook Street and Murihiku terranes were deposited in the proximal part of a fore-arc basin, whereas the Dun Mountain-Maitai Terrane represents the distal part of the same basin. Sedimentation in the Maitai Group ceased during the Middle Triassic (∼238 Ma), likely in response to a period of orogenesis at 235–230 Ma (Gondwanide Orogeny) that is widely recognized throughout the southwest Pacific. 相似文献
855.
雄安新区是国家层面打造的又一个具有重要战略意义的新区,及时准确掌握该地区的土地利用详情具有重要意义。本文利用10 m分辨率的Sentinel-2影像对雄安新区2016—2019年的土地利用进行分类,进而分析该地区的土地利用时空演变。共测试了决策树、随机森林和支持向量机3种分类器,进而获得最高精度的土地分类结果图;同时,利用随机森林的特征排序功能分析了不同特征的重要性。结果表明,雄安新区的耕地、林地、水生植物面积总体均呈显著减少趋势,建设用地面积变化最为显著,表明雄安新区正在进行中、快速的城市化发展。本研究得到的10 m分辨率土地利用专题图和分析结果对于雄安新区的及时监测与规划有着重要参考意义。 相似文献
856.
《Urban geography》2013,34(8):647-671
Centrality within a city and neighborhood characteristics have often been used as indicators of access to employment and services in statements about urban form and accessibility, but there are reasons to question the appropriateness of doing so. This paper evaluates the importance of geographic context within the urban environment (both location within cities as well as neighborhoods characteristics) for individuals in Portland, Oregon. Because conventional accessibility measures cannot incorporate individual characteristics, space-time individual accessibility measures were used with multilevel modeling to isolate the effects of individual level variations from that of geographical context. The results show that the influence of context on individual accessibility is weak, as accessibility tends to reflect individual and household characteristics rather than the local urban environment. Accessibility cannot be determined from location within cities, or from land uses around an individual's home, implying that the use of urban design to influence accessibility is inappropriate. 相似文献
857.
C. G. Murray 《Australian Journal of Earth Sciences》2013,60(7):899-925
The Princhester Serpentinite of the Marlborough terrane of the northern New England Orogen is a remnant of upper mantle peridotite that was partially melted at an oceanic spreading centre at 562 Ma, and subsequently interacted with Late Devonian island arc basalts in an intra-oceanic supra-subduction zone (SSZ) setting. The full range of rare-earth element (REE) contents, including U-shaped patterns, can be explained by a single process of reaction of partially melted, depleted peridotite with Late Devonian calc-alkaline and island arc tholeiite magmas by equilibrium porous flow, fractionating the REE by a chromatographic column effect. The Northumberland Serpentinite on South Island of the Percy Group has similar REE and high field strength element (HFSE) contents to the most depleted samples of the Princhester Serpentinite, supporting a common origin. However, spinel compositions suggest that the Northumberland Serpentinite interacted with boninitic magmas. The REE and mineral geochemistry indicates that the Princhester and Northumberland Serpentinites both represent part of the mantle component of a disrupted SSZ ophiolite. The ophiolite is considered to have formed above an east-dipping subduction zone, based on the geochemistry of Devonian island arc basalts between Mt Morgan and Monto, which include compositions identical to dykes and gabbroic blocks within the Princhester Serpentinite. Blockage of the subduction zone by collision with the Australian continent during the Late Devonian led to slab breakoff and the reversal of subduction direction, trapping the Late Devonian ophiolite in a forearc position. Its location, in a forearc setting above a growing accretionary wedge, conforms to the definition of a Cordilleran-type ophiolite. This interpretation is consistent with current views that most ophiolites are formed from young, hot and thin oceanic lithosphere at forearc, intra-arc and backarc spreading centres in a SSZ setting, and that emplacement follows genesis by 10 million years or less. Late Devonian crustal growth may have been widespread in the New England Orogen, because the disrupted ophiolite assemblage of the Yarras complex in the southern New England Orogen is probably of this age. Extensional tectonism at the end of the Carboniferous dismembered the Princhester – Northumberland ophiolite, removed the crustal section, and produced windows of accretionary wedge rocks within the fragmented ophiolite. The Princhester Serpentinite, together with fault slices of metasedimentary rocks, was thrust westward as a flat sheet over folded strata of the Yarrol Forearc Basin by a Late Permian out-of-sequence thrust during the Hunter – Bowen Orogeny, completing the emplacement of the Marlborough terrane. The Princhester and Northumberland Serpentinites could have been displaced by strike-slip movement along the Stanage Fault Zone or an equivalent structure. There is no record in the northern New England Orogen of SSZ ophiolites and volcanic arc deposits of Cambrian age, as exposed along the Peel Fault. Partial melting of the Princhester Serpentinite at an oceanic spreading centre at 562 Ma, recorded by mafic intrusives displaying N-MORB chemistry, was an earlier event that was outboard of any Early Paleozoic subduction zone along the margin of the Australian continent, and cannot be regarded as representing the early history of the New England Orogen. It is possible that the formation of intra-oceanic arcs in latest Silurian and Devonian time was the first tectonic event common to both the southern and northern New England Orogen. 相似文献
858.
AbstractFor a given increment of deformation, stretching lineations can be defined either by old grains or by new grains.Progressive strain accumulated in a matrix causes reorientation of old grains. The velocity field acting within a grain depends on the degree of non-coaxiality of the progressive strain in the matrix, and on the competence contrast between grain and matrix (e.g. Lister & Williams, 1983). Deformed populations of old grains do not systematically track the principal directions of finite stretch; this depends on the mechanical behavior of the grains. On the other hand, these populations may be good markers of finite strain magnitude, provided that the initial distribution is known.In contrast, the statistical shape orientation distribution of population of new grains cannot be related in a simple way to the finite strain magnitude, but their preferred orientation is considered to be the best indicator of the principal directions of finite stretch.An example is considered from the schistes lustrés near Kenestrelle (Val Chisone, Western Alps), where the observed mineral lineation is attributed to a late E-W stretching event in the alpine orogenic history. 相似文献
859.
雄安新区作为多要素城市地质调查试点城市,急需建立城市地质标准,为高水平现代化城市管理提供全方位技术支撑。从城市地质与现代城市行政管理有机融合的角度角度出发,通过分析我国城市地质标准现状和雄安新区规划建设需求,研究提出雄安多要素城市地质标准体系。研究表明:高起点规划、高标准建设雄安新区,需要建立一套系统的、完整的、先进的多要素城市地质标准体系;标准体系应该包括空间、资源、环境和灾害等子体系:空间涵盖全域、重点区、特色小镇、工程建设场地等四方面,资源涵盖地热、矿泉水、地下水等三方面,环境涵盖土壤质量、地下水质量、湿地质量等三方面,灾害涵盖地面沉降、地裂缝、地震、砂土液化、地面塌陷等五方面。与雄安新区规划、建设、运行等不同阶段城市管理密切结合,需要研制30项城市地质技术标准,包括空间标准6项、资源标准9项、环境标准7项、灾害标准8项。 相似文献
860.
A new cerambycid beetle (Qitianniu zhihaoi gen. et. sp. nov.) is described on the basis of a single specimen embedded in Cretaceous Burmese amber (ca. 99 Ma). Unusual characteristics are hairy antennae and large lateral eyes, a pronotum with lateral margin, and sinuate protibiae. Based on a phylogenetic analysis, the systematic position of Qitianniu is still uncertain and we provisionally place it as Cerambycidae incertae sedis. 相似文献