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91.
本文对松辽盆地东南部后五家户气田划分出22种沉积微相,建立7种相层序,分析了扇三角洲及三角洲沉积环境对天然气成藏的控制作用。指出了扇三角洲前缘砂体和三角洲前缘砂体较为发育,沉积物源来自气田东北部和东南部两个方向。后五家户气田多为构造—岩性气藏和岩性气藏。 相似文献
92.
Introduction The Western Kunlun Mountain Pass M=8.1 earthquake occurred on November 14, 2001 is the other M=8 earthquake occurred 50 years after Dangxiong, Tibet M=8.0 earthquake in Chinese mainland. The earthquake has caused the attention of the seismologists in the following aspects: 1) The fracture length is more than 400 km, which is far away from the estimated length by the statistic empirical function between the magnitude and the fracture length (WANG, et al, 2002); 2) The aftersh… 相似文献
93.
94.
Ashwani Kumar S. C. Gupta A. K. Jindal Sanjay Jain Vandana 《Journal of Earth System Science》2003,112(3):391-395
Following a large-sized Bhuj earthquake (M
s = 7.6) of January 26th, 2001, a small aperture 4-station temporary local network was deployed, in the epicentral area, for
a period of about three weeks and resulted in the recording of more than 1800 aftershocks (-0.07 ≤M
L <5.0). Preliminary locations of epicenters of 297 aftershocks (2.0 ≤M
L <5.0) have brought out a dense cluster of aftershock activity, the center of which falls 20 km NW of Bhachau. Epicentral
locations of after-shocks encompass a surface area of about 50 × 40 km2 that seems to indicate the surface projection of the rupture area associated with the earthquake. The distribution of aftershock
activity above magnitude 3, shows that aftershocks are nonuniformly distributed and are aligned in the north, northwest and
northeast directions. The epicenter of the mainshock falls on the southern edge of the delineated zone of aftershock activity
and the maximum clustering of activity occurs in close proximity of the mainshock. Well-constrained focal depths of 122 aftershocks
show that 89% of the aftershocks occurred at depths ranging between 6 and 25 km and only 7% and 4% aftershocks occur at depths
less than 5 and more than 25 km respectively. The Gutenberg-Richter (GR) relationship, logN = 4.52 - 0.89ML, is fitted to the aftershock data (1.0<-M
L<5.0) and theb-value of 0.89 has been estimated for the aftershock activity. 相似文献
95.
The Gondwana successions (1–4 km thick) of peninsular India accumulated in a number of discrete basins during Permo-Triassic period. The basins are typically bounded by faults that developed along Precambrian lineaments during deposition, as well as affected by intrabasinal faults indicating fault-controlled synsedimentary subsidence. The patterns of the intrabasinal faults and their relationships with the respective basin-bounding faults represent both extensional and strike-slip regimes. Field evidence suggests that preferential subsidence in locales of differently oriented discontinuities in the Precambrian basement led to development of Gondwana basins with varying, but mutually compatible, kinematics during a bulk motion, grossly along the present-day E–W direction. The kinematic disparity of the individual basins resulted due to different relative orientations of the basement discontinuities and is illustrated with the help of a simple sandbox model. The regional E–W motion was accommodated by strike-slip motion on the transcontinental fault in the north. 相似文献
96.
Andesitic pillow lavas containing biogenic, solid bitumen (SB) are a constituent of a Neoproterozoic volcanosedimentary sequence (Teplá-Barrandian unit, Bohemian Massif) in the Mítov area of the Czech Republic. A black shale formation that is crosscut by these andesitic basalts is 565 Ma old. Carbon disulfide extracts of two powdered samples of SB contain 0.2 and 0.3 ppm of C60, respectively, as determined by high-pressure liquid chromatography. The peak assignment based on retention time is fully supported by high-resolution electron ionization mass spectrometry (EI-MS). No C70 was detected, nor was C60 found in two other SB samples from this locality. Other investigated carbonaceous samples from Bohemia (coals and anthracites of Upper Paleozoic age and anthraxolite, graphitoids, and graphite of Upper Proterozoic age) did not contain fullerenes at concentrations above the detection limit of 0.01 ppm. The absence of C60 in these samples was confirmed by EI-MS. The proposed mechanism of fullerene formation involves a primary algal phase, generation of a hydrocarbonaceous mixture in the course of thermal evolution of the sedimentary series, and their high-temperature transformation related to the extrusion of basalt. An important feature for fullerene conservation was the enclosure of fullerenes in SB with a structure similar to glasslike carbon, where the fullerene was protected against oxidation. 相似文献
97.
Permeshwar S. Chauhan Mahesh C. Porwal Lalit Sharma Jay Devs.negi 《Journal of the Indian Society of Remote Sensing》2003,31(3):211-218
The review of study site have revealed the change in vegetation cover of Sal Dense to Sal Medium and Sal Open in 6 forest
Mosaics owing to biotic and abiotic conditions prevailing in the specific areas. Analysis carried out using thematic map derived
from aerial photograph of 1976 and satellite data of IRS 1C LISS III False Colour Composite (FCC) of March 1999 revealed the
cause for change in forest density classes. Deforestation, encroachment and agriculture have been identified as the underlying
causes, which have affected some specific locations to a marked extent. There has been a progressive and remarkable change
among vegetation classes from 1976 to 1999. It is evident from forest type and density map that Sal density has significantly
reduced from Sal Dense 65.61 % in 1976 to Sal Dense 11.12% in the year 1999 followed by Sal Open 11.18 % and Sal Medium 18.24
%. The overall change has been estimated to be 42.11% of the total forested area. 相似文献
98.
Sarbari Ghosh Utpal Kumar De Atmospheric Science Research Department of Physics Jadavpur University Calcutta India Received April revised July 《大气科学进展》1997,(1)
AComparativeStudyoftheAtmosphericLayersbelowFirstLiftingCondensationLevelforInstantaneousPre-MonsoonThunderstormOcurenceatAga... 相似文献
99.
Summary The rate of oceanic heat storage of the upper 200m of the Arabian Sea is explained in terms of net air-sea heat flux (Q
F), heat change due to horizontal divergence and vertical motion (Q
V) and heat change due to lateral advection (Q
A). The analysis revealed that the heat storage of the Arabian Sea is mainly controlled byQ
V while the effect ofQ
A is much larger than expected. Parameterisation of summer cooling revealed that the depletion of energy from the mixed layer is mainly due to upwelling and horizontal advection though large amount of heat is accumulated due to net air-sea heat flux. The annual heat balance of the upper 200m of the Arabian Sea suggested large heat gain by air-sea exchange processes. About two third of this heat gain is compensated by horizontal advection and one third by vertical advection.With 4 Figures 相似文献
100.
Both ‘tanka’ and ‘beri’, the well-like structures made for storing drinking water fetched from distant places or superficially charged from the runoff water of the monsoon rains, are considered integral components of rural communities in the Thar Desert of Rajasthan State in north-western India.A. stephensi, the confirmed malaria vector in desert regions, breeds in these structures predominantly. 相似文献