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1.
Aleksandra Smyrak-Sikora Per Terje Osmundsen Alvar Braathen Kei Ogata Ingrid Anell Mark J. Mulrooney Valentin Zuchuat 《Basin Research》2020,32(5):949-978
World-class examples of fault-controlled growth basins with associated syn-kinematic sedimentary fill are developed in Upper Triassic prodelta to delta-front deposits exposed at Kvalpynten, SW Edgeøya in East Svalbard. They are interpreted to have interacted with north-westerly progradation of a regional delta system. The syn-kinematic successions consist of 4 to 5 coarsening-upward units spanning from offshore mudstones to subtidal heterolithic bars and compound tidal dunes, which were blanketed by regional, post-kinematic sandstone sheets deposited as laterally continuous, subaqueous tidal dune fields. The rate of growth faulting is reflected in the distribution of accommodation, which governs sedimentary architecture and stacking patterns within the coarsening-upward units. Fully compartmentalized basins (12, 200–800 m wide and c. 150 m high grabens and half grabens) are characterized by syn-kinematic sedimentary infill. These grabens and half-grabens are separated by 60–150 m high horsts composed of pro-delta to distal delta-front mudstones. Grabens host tabular tidal dunes (sandwaves), whereas half-grabens bound by listric faults (mainly south-dipping) consist of wedge-shaped, rotated strata with erosive boundaries proximal to the uplifted fault block crests. Heterolithic tidal bars (sand ridges) occur in narrow half-grabens, showing migration oblique to the faults, up the dipslope. Structureless sandstone wedges and localized subaqueous slumps that formed in response to collapse of the block crests were only documented in half-grabens. Late-kinematic deposition during the final stages of faulting occurred in partly compartmentalized basins, filled with variably thick sets of continuous sandstone belts (compound tidal dunes). 相似文献
2.
O. M. Khlystov E. E. Kononov H. Minami A. V. Kazakov A. V. Khabuev N. A. Gubin A. G. Chenskii 《Geography and Natural Resources》2018,39(1):33-38
A high-resolution bathymetric survey of the entire underwater slope in South Baikal was carried out for the first time by means of the multibeam echosounder. New elements were revealed in the underwater relief of the southern slope of the basin from the Kultuchnaya river to the Mysovka river, and a relevant regionalization was carried out into three areas according to the presence of ancient landforms and the intensity of the processes of their reworking, with the boundaries along the delta-front and the river fan of the Utulik and Pereemnaya. We reconstructed the formation process of the modern relief of this area of the underwater slope and determined a dominant role of the underwater-erosion processes in the formation of the modern relief, with the tectonic movements served as the “trigger” for them. The study revealed a direct correlation between the reworking of the ancient geomorphological surfaces and the occurrence of separate large underwater elevations or group ridges (remnants), canyons and linear depressions. It is determined that the pivotal role in the appearance of the modern relief of the underwater slope in the second area of extensive plano-convex (in section) and fan-shaped (in plan) delta-fronts of large rivers and debris fans enveloping the remnants. The existence of a steep underwater slope from the mouth of the Pereemnaya to the mouth of the Bol’shaya Tel’naya and of two large benches, and also the proximity of the maximum depths of the southern basin at the foot of this slope are explained by a more intense step-like lowering of this part of the lake when compared with the western part of the basin. This also accounts for the absence of large remnants in this part of the slope. The area of occurrence of lacustrine-fluvial and lacustrine-delta deposits of the Tankhoi paleobasin within the southern basin of Baikal is reconstructed. Four new hydrate-bearing structures associated with these deposits and morphologically pronounced in the vertex parts of the remnants were discovered. The morphological exploration indicators of the presence of new accumulations of gas hydrates on the underwater slopes of Baikal have been expanded. 相似文献
3.
Soil evolution and subalpine ecosystem changes in the French Alps inferred from geochemical analysis of lacustrine sediments 总被引：1，自引：0，他引：1
Brice Mourier Jerome Poulenard Christopher Carcaillet David Williamson 《Journal of Paleolimnology》2010,44(2):571-587
This study aimed to reconstruct the history of soil development, ecosystem changes and associated erosional processes in a
small mountain lacustrine basin at the decennial to millennial scale. Geochemical proxies of soil evolution were analysed
in the Holocene lacustrine sediments and peats from Thyl Lake, Maurienne Valley, French Alps. Podzolization and chemical weathering
processes were assessed using secondary Al- and Fe-bearing phases together with major and Rare Earth Elements (REE). The resulting
proxy records, spanning ca. 4,400 years between 8.6 and 4.2 cal ka BP, indicate that progressive pedogenesis occurred after deglaciation in a relatively
stable subalpine ecosystem. As shown by the associated increase in Al- and Fe-bearing phases and some REE fractions, the establishment
of a mixed cembra pine ecosystem from ca. 7.2–6.5 ka BP was associated with enhanced podzolisation processes in the catchment. The progressive soil development was
followed by a rapid transformation of the local environment and plant cover (the open waters of the lake were replaced by
a confined peat environment) together with changes in forest fire regimes from ca. 6.8 ka BP. Depleted REE patterns, associated with low contents of secondary Al and Fe, suggest a decrease in chemical weathering
and podzolization in the catchment at that time, possibly associated with local intensification of weathering and drainage
processes in a relatively acidic peat environment. The higher variability of cembra pine and the increased abundance of sedge
and other herbaceous plant remains in the lake sediment indicate semi-open vegetation environments from 5.7 cal ka BP onwards.
Whereas fire events and plant cover appear to be significantly related, the soil processes seem primarily linked to vegetation
composition, and secondarily to changes in fire regime. 相似文献
4.
The dynamics of erosion and soil deflation processes in the Russian part of the Selenga basin is considered for the period of agrarian land use in relation to a combination of natural and anthropogenic factors. Periods with a different directedness and intensity of the processes have been identified. It is shown that a large-scale degradation of lands within the Selenga basin was caused by massive destruction of forests in the first half of the 19th century. Special attention is centered on the disastrous manifestations of the processes associated with extreme high-intensity storm rains or with heavy droughts. Strategies are suggested for optimizing land use practices in order to avoid a further degradation of soil cover. 相似文献
5.
The magnitude of mass flux is closely associated with biogeochemical watershed processes, which can generate a considerable amount of pertinent information. Moreover, both the accuracy and precision of mass flux estimation results directly affects the perception of the ecological environmental status, which in turn affects both the formulation and implementation of river basin management planning. In practical applications, the true value of flux is unknown and can only be estimated. Flux results obtained using different monitoring and estimation methods also differ significantly. However, in existing studies on mass flux associated with biogeochemical watershed interfaces, the application of monitoring and estimation methods lacks uniform criteria or references. Accordingly, this study summarizes and deconstructs results from recent studies on biogeochemical watershed interface processes and compares the advantages, disadvantages and applicability of the monitoring and estimation methods used by these studies. This particular study is intended to be used as a reference for the selection of flux calculation methods. 相似文献
6.
We assessed the level of geomorphological risk associated with the occurrence of erosion processes on the western slope of the Tom’-Yaya interfluve (West-Siberian Plain). We suggest the technique for points-based risk assessment in technogenically modified and naturally occurring geomorphological systems. Using the Luchanovskii area as an example, we identified the zones of increased, moderate and low risk levels. 相似文献
7.
AbstractScholarship on collaboration in natural resource management is restricted by a lack of large-N assessments and mixed methods approach to examine relationships between collaborative structures and processes, and management actions and outcomes. This paper examines the relationship between perceived levels of collaboration, collaborative process indicators, and benefits of USDA Forest Service stewardship contracts at a broad spatial and temporal scale using mixed methodology. This study found higher levels of collaboration were strongly associated with jointly initiated processes that included a breadth of interests and utilized a broad range of outreach mechanisms and opportunities for engagement. Highly collaborative processes were closely linked with attaining project objectives and social and economic benefits. Findings contribute to defining collaboration by uncovering the relationship between perceived levels of collaboration, the role of process characteristics, and perceived benefits of collaborative stewardship contracting processes through a large-N dataset (n?=?1,064) and case study (n?=?61) findings. 相似文献
8.
Regulation, Land Development and the Contested Countryside 总被引：1，自引：0，他引：1
This paper attempts to reorientate locality specific studies of counterurbanisation within the wider processes of global and national socio-economic change. It draws on concepts of Regulation Theory and begins with an explanation of the global and national influences associated with rural restructuring. These influences, together with the emergence of a reconstituted rurality, are traced through to the local level using Bridgetown in the south-west of Western Australia as a vehicle for conceptual analysis. 相似文献
9.
Nick Revington 《The Professional geographer》2018,70(1):1-10
Challenges arising from changing demographics, expensive housing, and precarious labor have prompted recent interest in the residential geographies of young adults. Yet, despite attention to young adults' diverse housing pathways, I argue that greater focus is needed on the place-based and spatial underpinnings and effects of particular housing pathways: Connections to urban processes of “youthification”—the concentration of young adults in dense neighborhoods—and “studentification”—whereby an area becomes dominated by university students—remain underdeveloped, as do linkages between these phenomena and gentrification. I explore these connections through a critical review of extant literature to show that the enactment of some pathways is associated with particular urban processes, which might foreclose certain pathways for other individuals. Finally, I identify three crucial areas of inquiry: (1) how youthification, studentification, and gentrification interact; (2) how these processes shape and are shaped by diverging individual housing pathways; and (3) how differences among young adults such as race, ethnicity, and gender intersect with age in the course of these processes. 相似文献
10.
Presented are the results from a geoecological monitoring of natural and anthropogenic changes in the situation in the desert-steppe
region of Inner Asia (Great Lakes Depression), based on space images at intervals of 27–30 years, published data, and the
authors’ ground-based observations. The changes identified in this study are associated with global hydrothermal processes,
and with the influence of anthropogenic pressure. 相似文献
11.
土壤侵蚀模型是定量研究土壤侵蚀的有效工具,探讨土壤侵蚀模型研究中的有关问题对于土壤侵蚀模型的发展及相关研究具有重要意义。从模型的过程模拟、模型时空尺度变异、模型验证和不确定性几方面对模型研究现状及局限进行了归纳和分析,认为:不同过程的模拟及其模拟方法的不同导致了各具特色的土壤侵蚀模型的出现;大多水蚀模型是对不同时空尺度上的水流及相应侵蚀过程进行模拟预测,在不同的时空尺度上,不同的侵蚀过程占主导地位;现实过程和现象的复杂性、观测方法和手段的限制以及模型的自身的局限性是导致土壤侵蚀模型预测的不确定性的主要原因;与GIS结合的强预测力、低数据要求的模型是土壤侵蚀模型发展的趋势。 相似文献
12.
de Quadros Telmo F. P. Koppe Jair C. Strieder Adelir J. Costa João Felipe C. L. 《Natural Resources Research》2003,12(1):57-65
A large number of mineral deposits are associated with hydrothermal processes, especially auriferous deposits. In such processes, studies on percolating fluids may indicate the presence of potash (K), among other elements. In this study, aerogammaspectrometric data-processing methodologies are evaluated, especially those methods based on the suppression of the primary contribution of potassium, the result of lithological and soil variations, and to environmental conditions. Resulting maps point out the contribution of hydrothermal K. This processing procedure was used because of the association of hydrothermal K and auriferous mineralizations according to the deposit model defined for the studied region. Intensity maps locate the areas with great influence of hydrothermal K. Data integration required to improve a change in the gammaspectrometric data processing in order to positively correlate hydrothermalised areas. Data integration could distinguish high and medium favorable targets for mineral exploration of lode-Au deposits in the studied region. 相似文献
13.
The isotope ratios in precipitation are associated with various meteorological processes and display obvious spatial and temporal
distributions, and thus can be used as important techniques in inversing atmospheric processes, tracing vapor sources, and reflecting
the local weather and climate conditions. The composition and distribution of stable isotopes in precipitation in China are
summarized and the factors that influence isotope ratios are elucidated. An overview of related research progress in China during
the past several decades is presented and the prospects for future work in this subject area are described. 相似文献
14.
《Geomorphology》2003,49(3-4):177-204
In this paper, a detailed study of the submarine geomorphology surrounding the Balearic Promontory (western Mediterranean), a northeast prolongation of the Neogene Betic Range in southern Spain, is presented from a series of high-resolution tools including swath bathymetry and seismic reflection profiling. The study identifies the main features of the continental shelf, slope and basins surrounding the Balearic Islands. We show a variety of seafloor relief that owes its origin to several geologic processes, which ultimately control the transport of sediment from the shallower areas to the deep basin. The most important processes are erosion of the shelf and upper slope (terraces associated with different Quaternary sea-level stands and canyons), transport and sediment deposition in the lower slope and base-of-slope by turbidity currents, volcanism and instability processes (landslides scarps and debris lobes). The swath data show that tectonics plays an important role in shaping the submarine slopes of Eivissa and Formentera, the two southernmost islands, as well as its interplay with sedimentary processes, especially mass wasting. Finally, several areas show evidence of pockmarks, which indicate that fluid migration take place in the sediments, probably conditioning several other processes such as mass wasting. 相似文献
15.
This article uses discourse analysis techniques associated with Foucauldian archaeology to examine the two international charters developed by the International Geographical Union Commission on Geographical Education (IGU-CGE), the original one in 1992 and the revised version endorsed in 2016 at the Beijing conference. The examination considers the consultation and development processes before outlining similarities and differences in the messages communicated and how discourses have changed through time. The article concludes with recommendations for the geography education community for the future. 相似文献
16.
137Cs法在风沙过程研究中的应用前景 总被引：6，自引：3，他引：3
137Cs法在土壤侵蚀与泥沙沉积研究中已得到普遍的应用,但在风沙过程研究中尚未引起足够的重视。针对风沙过程研究中存在的有关问题,对137Cs法的应用前景作了展望,并提出了137Cs应用的若干建议。 相似文献
17.
The geography of sport has received relatively little attention from those interested in processes of rural social and economic change. This is despite the important role that sport plays in the structure of rural communities and regions. In addition to the obvious health benefits associated with physical activity, sport contributes to community identity and provides opportunities for social interaction. There is, however, considerable evidence to suggest that processes of restructuring are having direct impacts on sport in rural areas. Drawing on a case study from rural Western Australia, this paper argues that economic adjustment in the farming and business sectors, service withdrawal, and population decline are just some of the changes undermining the viability of sporting clubs in rural areas. We suggest that while sporting clubs have tended to be resilient in the face of restructuring, it is also clear that one of the outcomes is a changing geography of sport in declining rural areas. 相似文献
18.
盐沼前缘陡坎是潮滩环境中盐沼与粉砂—淤泥质光滩交界处的独特地貌形态,研究其形成过程与机理有助于理解盐沼湿地对潮滩发育及其稳定性的影响。根据江苏中部海岸盐城自然保护区核心岸段互花米草盐沼前缘陡坎形态参数（凹槽长度、凹槽宽度和陡坎高度）的分析,发现不同的形态参数组合对应于不同的陡坎演化阶段。根据陡坎形态特征差异,可将盐沼前缘陡坎韵律性形态发育过程分为三个阶段,而这三阶段的交替旋回过程与近岸波向的季节性变化有关。陡坎处的地貌特征与前缘光滩的沉积物特征表明陡坎形态特征形成与波浪作用有关,且显著的陡坎韵律性形态能够部分地应用边缘波理论来解释。 相似文献
19.
Engineered channel controls limiting spawning habitat rehabilitation success on regulated gravel-bed rivers 总被引：1，自引：0，他引：1
In efforts to rehabilitate regulated rivers for ecological benefits, the flow regime has been one of the primary focal points of management strategies. However, channel engineering can impact channel geometry such that hydraulic and geomorphic responses to flow reregulation do not yield the sought for benefits. To illustrate and assess the impacts of structural channel controls and flow reregulation on channel processes and fish habitat quality in multiple life stages, a highly detailed digital elevation model was collected and analyzed for a river reach right below a dam using a suite of hydrologic, hydraulic, geomorphic, and ecological methods. Results showed that, despite flow reregulation to produce a scaled-down natural hydrograph, anthropogenic boundary controls have severely altered geomorphic processes associated with geomorphic self-sustainability and instream habitat availability in the case study. Given the similarity of this stream to many others, we concluded that the potential utility of natural flow regime reinstatement in regulated gravel-bed rivers is conditional on concomitant channel rehabilitation. 相似文献
20.
Auckland's post-suburban landscape is associated with new mixed-use apartment developments. When located in former industrial sites, these emergent residential and retail spaces constitute new-build gentrification and carry the potential to rupture existing people/place dynamics. This article examines material and socio-cultural processes associated with the redevelopment of an industrial quarry in Three Kings, Auckland. It is argued that the redevelopment constitutes a physical refashioning of a former industrial space located within a traditional working-class community. The development involves a remaking of the material and socio-cultural fabric of the neighbourhood and aligns with new-build gentrification practices. 相似文献