Imagining the borderlands: Contending stories of a resource frontier in Muang Sing     

Yayoi Fujita Lagerqvist 《Singapore journal of tropical geography》2013,34(1):57-69

Muang Sing in Luang Namtha province, an administrative district of northern Laos bordering Myanmar and China, has been portrayed by the Lao government and international development agencies as a ‘poor’ rural region in need of development. To developers, Muang Sing's remoteness from major towns and the livelihoods of ethnic people such as the Akha in the uplands based on swidden agriculture and opium production characterized ‘poverty’. To address this rural poverty, state and development agencies devised land use zoning that would demarcate and regulate various land uses in line with a rural development plan for the district. This vision for regulated development began to go awry, however, as farmers and traders in Muang Sing launched their own rapid social and economic changes. In contrast to the official image of a backward rural district in need of outside assistance, this paper portrays farmers and local entrepreneurs of the Muang Sing borderlands as actively transforming their lives and agricultural landscapes. This paper challenges the official version of a remote, poor district untouched by regional trade through a focus on narratives of local people. Ethnographic research reveals the dynamic micro‐processes of agrarian transformation during recent decades to highlight the centrality of borderland people in reworking their lives and agricultural landscapes through cross‐border relationships in China.  相似文献   

Shimajiri Group equivalent sedimentary rocks dredged from sea knolls off Kume Island,central Ryukyus: Implications for timing and mode of rifting of the middle Okinawa Trough back-arc basin     

Ritoko Kikunaga  Ke-han Song  Shun Chiyonobu  Kazuhiko Fujita  Ryuichi Shinjo  Kyoko Okino 《Island Arc》2021,30(1):e12425

The late Cenozoic geohistory of the Ryukyu arc is closely related to the rifting history of the Okinawa Trough. The submarine geology and stratigraphy of areas around Kume Island, which is situated near the eastern rifted margin of the middle Okinawa Trough, provide key constraints to understand the timing and mode of Okinawa Trough rifting. Here we report the lithology of sedimentary rocks dredged along slopes of ~1000-m-deep sea knolls located north and northwest off Kume Island, and their depositional ages determined by calcareous nannofossils and strontium (Sr) isotope analyses. Various types of sedimentary rocks, such as siltstone, very fine-grained sandstone, medium-grained sandstone, fossiliferous coarse-grained sandstone, and tuffaceous sandstone, were recovered at two dredge sites. These sedimentary rocks are lithologically similar to those in the Aka Formation and a part of the Maja Formation of the Shimajiri Group in nearby Kume Island. Calcareous nannofossils and Sr isotope analyses indicate their depositional ages from the early Pliocene to the early Pleistocene, which are generally consistent with those of the Aka Formation. The finding of the dredged rocks similar in lithology and ages to the Aka Formation indicates that marine deltaic area continued toward north and northwest from Kume Island during these periods. The presence of the Shimajiri Group equivalent sedimentary rocks at the dredge sites are likely related to the main rifting of the Okinawa Trough after ca. 2 Ma in the central Ryukyus.  相似文献   

Paleoenvironmental interpretations of Quaternary reef deposits based on comparisons of 10 selected modern and fossil larger foraminifera from the Ryukyu Islands, Japan     

Kazuhiko  Fujita  Hiroaki  Shimoji  Koichi  Nagai 《Island Arc》2006,15(4):420-436

Abstract A new method for reconstructing depositional environments of larger foraminifera‐bearing limestones is proposed. First, depth and spatial distributions of empty tests of 10 foraminiferal taxa in a 1–2 mm size fraction were examined using 32 surface sediment samples collected from depths shallower than 200 m, located to the west of Miyako Island, Ryukyu Islands, northwest Pacific. Distributional ranges of empty tests in the 1–2 mm size fraction appear to be more limited than those including other size fractions in previous reports, partly because larger empty tests of each taxon are less easily transported than smaller ones. Multivariate analyses (Q‐mode cluster analysis and non‐metric multidimensional scaling ordination) based on binary (presence/absence) data of the 10 taxa delineate four sample groups, each of which corresponds to different depositional environments: nearshore zone/bay inlet; back‐reef to fore‐reef; outer shelf to shelf slope; and shelf slope distant from coral reefs. Next, these modern data were applied to reconstruct the depositional environment of a rock section distributed in the Shiratorizaki area (Irabu Island, Ryukyu Islands), which consists of larger foraminiferal limestone of the Pleistocene Ryukyu Group. Multivariate analyses were performed on the fossil plus the modern foraminiferal data to explore the possible relationship of the fossil associations with variations in modern associations, demonstrating that the fossil foraminiferal associations resemble the modern outer shelf associations. The modern analog technique was also applied to estimate paleobathymetry using fossil foraminiferal data. The results indicate that the section studied was deposited in outer shelf environments at depths between 53.5 and 98.6 m. These paleoenvironmental interpretations are consistent with previous studies based on sedimentary facies and the computer‐based expert system. The modern dataset and methods used in our work would be particularly useful for paleoenvironmental reconstructions of Quaternary reef and shelf carbonates along active margins of the northwest Pacific.  相似文献   

Cenomanian (Upper Cretaceous) carbon isotope stratigraphy of terrestrial organic matter for the Yezo Group, Hokkaido, Japan     

Go-ichiro  Uramoto  Tomotaka  Fujita  Akinori  Takahashi  Hiromichi  Hirano 《Island Arc》2007,16(3):465-478

Abstract Carbon isotope fluctuations of sedimentary organic matter along the two geological traverses in the Yezo Group, Hokkaido, northern Japan, elucidate a detailed chemostratigraphy for the Cenomanian Stage on the northwestern Pacific margin. Visual characterization of the kerogen from mudstone samples shows that the major constituents of sedimentary organic matter originated as terrestrial higher plants. The atomic hydrogen/carbon ratios of the kerogen suggest that the original δ¹³C values of terrestrial organic matter (TOM) have not been affected significantly by thermal diagenesis. The patterns in two δ¹³C_TOM curves are similar and independent of changes in lithology and total organic carbon contents, which suggests that TOM was mixed sufficiently before the deposition in the Yezo forearc basin for the δ¹³C composition having been homogenized. In addition, this implies that the Hokkaido δ¹³C_TOM profiles represent the averaged temporal δ¹³C variations of terrestrial higher‐plant vegetation in the hinterlands of northeast Asia during Cenomanian time. Three shorter‐term (ca. 0.1 my duration) positive‐and‐negative δ¹³C_TOM fluctuations of ∼1‰ are present in the Lower to Middle Cenomanian interval in the Yezo Group. On the basis of the age‐diagnostic taxa (ammonoids, inoceramids and planktic foraminifers), these discrete δ¹³C_TOM events are interpreted to be correlated with those in the δ¹³C curves of pelagic carbonates from European basins. The correlation of δ¹³C events between the European and Yezo Group sections suggests that the shorter‐term δ¹³C fluctuations in Cenomanian ocean‐atmosphere carbon reservoirs are useful for global chemostratigraphic correlation of marine strata. In particular, the correlation of δ¹³C fluctuations of the so‐called ‘Mid‐Cenomanian event’ (MCE) implies: (i) the δ¹³C variations of global carbon reservoir during the MCE are precisely recorded in the δ¹³C_TOM records; and (ii) the MCE δ¹³C_TOM event is an efficient chronostratigraphic index for the Lower/Middle Cenomanian boundary of the Mid‐Cretaceous sequences.  相似文献   

Reaction of juvenile flounder to grid separators   总被引：1，自引：0，他引：1  

Matsushita  Yoshiki; Fujita  Kaoru; Ikegami  Naoya; Ohata  Satoshi 《ICES Journal of Marine Science》2004,61(7):1174-1178

  相似文献   

Modelling of depth phases and source processes of some central Aleutian earthquakes     

Tai-Lin Hong  Kazuya Fujita 《Earth and Planetary Science Letters》1981,53(3):333-342

Short-period synthetic seismograms are computed to determine the relative amplitudes and arrival times of P, pP, pwP (water surface reflection), and sP phases. Except along nodal planes of upgoing p, pwP is of greater amplitude than sP. For central Aleutian earthquakes, pwP dominates over sP and pP at North American stations for thrust mechanisms and modelled crustal structures. The pwP phase is clearly identified in three Aleutian events and can be used to constrain focal depths. Complex fracturing processes are identified in two of the events. In simple events, smaller phases which are consistent from station to station can be identified as sub-surface reflections and used for modelling the structure of the forearc.  相似文献   

Flow behavior of large-scale pyroclastic flows — Evidence obtained from petrofabric analysis     

Tadahide Ui  Keiko Suzuki-Kamata  Rumi Matsusue  Kei Fujita  Hideya Metsugi  Mami Araki 《Bulletin of Volcanology》1989,51(2):115-122

The grain orientations within the matrix of two large-scale welded, two small-scale nonwelded and two nonwelded low-aspect ratio pyroclastic flow deposits are measured to analyze flow behavior. Preferred grain alignments are especially apparent in the middle part of layer 2 of each deposit. Preferred grain alignments do not vary laterally within a 10 m interval. The grain alignments obtained are radial from the source caldera, especially in proximal to medial and plateau-forming facies of pyroclastic flow deposits. Grain alignments are controlled by valley-channel directions for the valley-ponded facies of pyroclastic flow deposits, especially at medial to distal locations. Such local topographic factors strongly affect the data for high-aspect ratio and smallscale deposits, and weakly affect the data for widespread low-aspect ratio pyroclastic flow deposits. This work suggests that grain alignment analysis should be used with care when attempting to determine the location of an unknown source.  相似文献   

Soil chemical alteration due to slaughterhouse waste application as identified by spectral reflectance in São Paulo State,Brazil: an environmental monitoring useful tool     

José A. M. Demattê  Julianne de Castro Oliveira  Tiago Rodrigues Tavares  Leonardo Ramirez Lopez  Fabrício da Silva Terra  Suzana Romeiro Araújo  Caio Troula Fongaro  Stoécio Malta Ferreira Maia  Francisco Fujita de Castro Mello  Rodnei Rizzo  Simone Vicente  Marco Antonio de Melo Bortolleto  Pedro Henrique Ramos Cerqueira 《Environmental Earth Sciences》2016,75(18):1277

  相似文献   

Evaluation of various satellite sensors for waterline extraction in a coral reef environment: Majuro Atoll, Marshall Islands   总被引：4，自引：0，他引：4  

Hiroya Yamano  Hiroto Shimazaki  Tsuneo Matsunaga  Albon Ishoda  Caleb McClennen  Hiromune Yokoki  Kazuhiko Fujita  Yoko Osawa  Hajime Kayanne 《Geomorphology》2006,82(3-4):398-411

The ability of five satellite sensor bands (IKONOS band 4, Terra ASTER bands 3 and 4, and Landsat ETM+ bands 4 and 5) was examined to extract the waterline at coral reef coasts (Majuro Atoll, Marshall Islands) using different wavelength regions (near infrared [NIR] and shortwave infrared [SWIR]) and different spatial resolutions (4, 15, and 30 m). After performing georeferencing and normalization of the images, density slicing was used to extract the waterline. Comparisons of extracted waterline positions with ground-level data for eight transects and global positioning system (GPS) tracks of the island shorelines showed that NIR bands were superior to SWIR bands because of the characteristics of the coral reef coasts, including a lack of foam and suspended sediments (which can affect the NIR wavelength region, if present) and the presence of remnant water on reef flats during low tide (which can affect the SWIR wavelength region). A linear relationship was found between the estimation errors of waterline positions and the spatial resolutions of the NIR sensors. Analysis on estimation errors and image costs showed that Terra ASTER band 3 was the most cost-effective sensor for extracting waterlines with reasonable accuracy. The results serve as general guidelines for using satellite-derived data to estimate intertidal topography and detect and monitor shorelines in coral reef environments.  相似文献   

Analysis of a microwave backscattering mechanism from a small urban area imaged with SIR-C     

Fujita  M. Miho  Y. 《Geoscience and Remote Sensing Letters, IEEE》2006,3(1):10-14

We analyzed the Spaceborne Imaging Radar C (SIR-C) imagery of a small urban area to characterize backscattering mechanisms. The results were compared with the building density so that we could relate the polarimetric backscattering characteristics with urban structures. Relative contributions of odd-bounce, double-bounce, and cross-polarized scatterings were evaluated as a function of the building density for small and large incidence angles. Their behaviors were characterized with respect to urban structures at small and large incidence angles.  相似文献