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761.
Guadalupian (Middle Permian) Conodont Faunas at Shangsi Section, Northeast Sichuan Province 总被引:1,自引:0,他引:1
This study recovered the Guadalupian conodont faunas from Shangsi (上寺) Section in Northeast Sichuan (四川). Four genera and nine species were identified, and three conodont zones were recognized and established; they include Jinogondolella nankingensis Zone, J. aserrata Zone, and J. postserrata Zone. The Roadian and Wordian boundary is set in the interval 5 m from the top of Bed 86 by the first appearance of the conodont J. aserrata. The Wordian and Capitanian boundary is set in the interval 2.3 m from the top of the Bed 95 by the first appearance of J. postserrata. Most of the specimens demonstrated low color alteration index (CAI) as 1.5-3, indicating that most part of the Maokou (茅口) Formation may have the suitable thermal conditions for the formation of oil source rocks. 相似文献
762.
Error sources which decrease the accuracy of GPS in absolute velocity determination have been changed since SA was turned off. Firstly, quantities of all kinds of error sources that influence velocity determination are analyzed. The potential accuracy of GPS absolute velocity determination is derived from both theory and field GPS data simulation. After that, two tests were carried out to evaluate the performance of GPS absolute velocity determination in the case of a static and an airborne GPS receiver and INS (Inertial Navigation System) instrument in kinematic mode. In static mode, the receiver velocity has been estimated to be several mm/s with the carrier-phase derived Doppler measurements, and several cm/s with the receiver generated Doppler measurements. In kinematic mode, GPS absolute velocity estimates are compared with the synchronized measurements from the high accuracy INS. The root mean square statistics of the velocity discrepancies between GPS and INS come up to dm/s. Moreover, it has a strong correlation with the acceleration or jerk of the aircraft. 相似文献
763.
Geochronological studies on the crust-derived Tianmenshan pluton were undertaken by SHRIMP zircon U-Pb dating and Ar-Ar dating of biotite, muscovite and K-feldspar, giving a petrogenetic age of 167 Ma. Owing to the closure systems in different minerals, the cooling history of the pluton can be determined with an age-temperature diagram. The late hydrothermal event has been recognized, which is related probably with mineralization. In terms of the comparative geochronological and petrologic records, it is concluded that there are some constrains on tectonic evolution and that the formation of the Tianmenshan pluton proceeded in a transition period from Indosinian post-orogeny extension to strong compressive tectonics. And the timing of the hydrothermal event matches the compressive climax of the Yanshanian orogeny. The temporal gap between granite emplacement and wolframite mineralization could last 10-20 Ma owing to the low cooling rate of the pluton. 相似文献
764.
Studies on rain-runoff process in the peripheral mountainous area of the Sichuan Basin, which is regarded as a key ecological shelter, will contribute to flood control and environmental protection for the Upper Yangtze River Basin. In two typical catchments--the Fujiang River Catchment and the Wujiang River Catchment, rainfall simulations have been conducted to study the rain-runoff processes of yellow soil and limestone soil in three types of land use--forestland, farmland and grassland. Results showed that (1) within the same rainfall process, overland flow occurs first on farmland, then on grassland, and finally on forestland; (2) soil surface coverage has a great impact on the occurrence and amount of overland flow. The runoff amount can increase 2-4 times after the coverage is removed; (3) the infiltration before the occurrence of overland flow will decrease because of higher gravel contents of soil, but it takes no effect on infiltration once overland flow becomes stable; (4) the runoff coefficient of the limestone soil forestland is greater than that of the yellow soil forest land, but less than that of the farmland; (5) three empirical infiltration models, including Horton' model, Kostiakov' model, and modified Kostiakov' model, were compared by using the observed results under rainfall simulation. The results showed that the Kostiakov' model performed better than both the Horton' model and modified Kostiakov model. According to the results of this research, the Kostiakov's model can be used to simulate rainfall infiltration when water erosion is modeled in the peripheral mountainous area of the Sichuan Basin. 相似文献
765.
U. K. Shanwad V. C. Patil H. H. Gowda G. S. Dasog 《Journal of the Indian Society of Remote Sensing》2008,36(4):375-386
The current study was taken up to investigate the utility of remote sensing and GIS tools for evaluation of Integrated Wasteland
Development Programme (IWDP) implemented during 1997–2001 in Katangidda Nala watershed, Chincholi taluk, Gulbarga district,
Karnataka. The study was carried out using IRS 1C, LISS III data of December 11, 1997 (pre-treatment) and November 15, 2002
(post-treatment) covering the watershed to assess the changes in land use / land cover and biomass that have changed over
a period of five years (1997–2002). The images were classified into different land use/land cover categories using supervised
classification by maximum likelihood algorithm. They were also classified into different biomass levels using Normalized Difference
Vegetation Index (NDVI) approach. The results indicated that the area under agriculture crops and forest land were increased
by 671 ha (5.7%) and 1,414 ha (11.94%) respectively. This is due to the fact that parts of wastelands and fallow lands were
brought into cultivation. This increase in the area may be attributed to better utilization of surface and ground waters,
adoption of soil and water conservation practices and changes in cropping pattern. The area under waste lands and fallow lands
decreased by 1,667 ha (14.07%) and 467 ha (3.94%), respectively. The vegetation vigour of the area was classified into three
classes using NDVI. Substantial increase in the area under high and low biomass levels was observed (502 ha and 19 ha respectively).
The benefit-cost analysis indicates that the use of remote sensing and GIS was 2.2 times cheaper than the conventional methods.
Thus, the repetitive coverage of the satellite data provides an excellent opportunity to monitor the land resources and evaluate
the land cover changes through comparison of images for the watershed at different periods. 相似文献
766.
V. Nagasubramanian P. V. Radhadevi R. Ramachandran R. Krishnan 《Journal of the Indian Society of Remote Sensing》2008,36(1):27-35
Rational Function Model (RFM) is the alternate sensor Model to the rigorous sensor model that allows end user to perform sensor-independent
photogrammetric processing. Nowadays, commercial off-the-shelf (COTS) digital photogrammetric work stations have incorporated
RFM as a method for image restitution. It is technically applicable to all types of airborne and space borne sensors. In this
paper, we describe the derivations of the algorithmic procedure for third order inverse and forward RFM method for 3-D reconstruction.
Model accuracy is evaluated for aerial image, TK-350 Russian image and IRS-1C PAN image. The results ensure that properly
constructed RFM are accurate enough to be used in place of the original rigorous models. The test results are reported and
summarised. 相似文献
767.
768.
Airborne LiDAR has found application in an increasing number of mapping and Geo-data acquisition tasks. Apart from terrain
information generation, applications such as automatic detection and modeling of objects like buildings or vegetation for
the generation of 3-D city models have been explored. Besides the height itself, height texture defined by local variations
of the height is a significant parameter for object recognition. The paper explores the potential of the analysis of height
texture as a cue for the automatic detection of objects in LiDAR datasets. A number of texture measures were computed. Based
on their definition and computation these measures were used as bands in a classification algorithm, and objects like buildings,
single trees, and roads could be recognized. 相似文献
769.
A. K. Singh P. K. Singh B. Lal A. N. Singh A. Mathur 《Journal of the Indian Society of Remote Sensing》2008,36(2):183-188
A World Bank-aided project on sodic land reclamation in Uttar Pradesh is being executed by U.P. Bhumi Sudhar Nigam, Lucknow,
and Remote Sensing Applications Centre, U.P., Lucknow has the responsibility of sodic land mapping for the execution of land
reclamation programme at the cadastral level. Sodic lands are mainly concentrated in the Gangetic alluvial plains but the
problem of sodicity is particularly acute in the canal-irrigated areas. A study of the distribution pattern of sodic lands
in canal and noncanal command areas in a reclamation site (covering 60 villages out of which sodic lands were mapped in 51
villages) of Etah district in Uttar Pradesh, indicates that 18.39 per cent area of the canal command villages was barren sodic
which was 13.41 per cent of the total geographical area of the site (15417 ha), however, 11.69 per cent area was recorded
to be barren sodic in the non-canal command villages which was only 3.16 per cent of the geographical area of the site. The
results of soil chemical analysis indicate that barren sodic lands of canal command area are saline-sodic with higher concentration
of soluble salts (pH2 >8.5, EC2 >4 dSm−1), however, those of non-canal command area are sodic (pH2 >8.5, EC2 <4 dSm−1). The post-monsoon ground level in the canal-irrigated areas was in the critical and semicritical zone (< 3.0 mbgl) whereas
it was well below the semi-critical zone in the non-canal command area, which indicates that the high ground water level is
a major factor to higher the area under sodicity. 相似文献
770.
H.B. Chauhan R.M. Dwivedi 《International Journal of Applied Earth Observation and Geoinformation》2008,10(2):181-1
Coastal zone assumes importance due to high productivity of ecosystems, man-made developmental activities, natural hazards and dynamic nature of the coast. As costal ecosystems are unique and fragile, understanding the impact of developmental activities on the sustainability of the coastal zone is very important. Remote sensing, because of repetitive and synoptic nature is an ideal tool for studying this. Time series data analyses for monitoring coastal zone require different type of sensors. Present study deals with atmospheric correction of satellite data, reflectance, selection of coastal features like, mudflat, mangroves, vegetated dune, coastal water, etc. and their inter-comparison using different sensor data of RESOURCESAT sensors. Reflectance values give better separateability for various coastal features in comparison to DN values. LISS IV can be used in place of LISS III or merged (LISS III + PAN) for long-term coastal zone studies. 相似文献