Journal of Geographical Sciences - Non-crop habitats have been suggested to impact local biodiversity significantly in agricultural landscapes. However, there have been few studies of the effects... 相似文献
For decades of exploration, geologists have made great achievements in the exploration of lacustrine carbonate rocks. By dissecting four typical cases of lacustrine carbonate rocks, such as Lucaogou Formation of Permian in Junggar Basin, Da'anzhai Section of Jurassic in Sichuan Basin, Cretaceous in Yin'e Basin and Oligocene in Qaidam Basin, the reservoir characteristics, hydrocarbon generating capacity and reservoir forming model of source rocks were analyzed. The results show that: Lacustrine carbonate reservoirs are generally dense, with nano-micron reservoir space as the main reservoir space, including dolomite intergranular pore, organism cavity and accumulation pore, micro-fracture system and its corrosion expansion pore. Saline environment is beneficial to dolomitization and can improve the reservoir capacity of lacustrine carbonate rocks, but most of the permeability is less than 0.1 mD. Lacustrine carbonate rocks have not only reservoir capacity, but also can be used as source rocks. The abundance of organic matter is not high and the maturity is generally low. However, dispersed soluble organic matter in source rocks can generate and expel hydrocarbons in large quantities at low maturity stage, which has high liquid hydrocarbon yield. Oil and gas reservoirs are characterized by "high initial production, large reduction of production and long-term low and stable production", and are typical "fracture-pore" reservoirs. Fracture networks provide migration pathways in the process of primary migration and accumulation of oil and gas in geological history and oil and gas exploitation nowadays. Oil and gas reservoirs are "continuous" unconventional reservoirs, which often form regional oil and gas field groups together with conventional reservoirs in adjacent areas. The research results lay a theoretical foundation for re-evaluating the exploration potential of lacustrine carbonate rocks. 相似文献
Zircon stability in silicate melts—which can be quantitatively constrained by laboratory measurements of zircon saturation—is important for understanding the evolution of magma. Although the original zircon saturation model proposed by Watson and Harrison (Earth Planet Sci Lett 64(2):295–304, 1983) is widely cited and has been updated recently, the three main models currently in use may generate large uncertainties due to extrapolation beyond their respective calibrated ranges. This paper reviews and updates zircon saturation models developed with temperature and compositional parameters. All available data on zircon saturation ranging in composition from mafic to silicic (and/or peralkaline to peraluminous) at temperatures from 750 to 1400 °C were collected to develop two refined models (1 and 2) that may be applied to the wider range of compositions. Model 1 is given by lnCZr(melt) = (14.297 ± 0.308) + (0.964 ± 0.066)·M − (11113 ± 374)/T, and model 2 given by lnCZr(melt) = (18.99 ± 0.423) − (1.069 ± 0.102)·lnG − (12288 ± 593)/T, where CZr(melt) is the Zr concentration of the melt in ppm and parameters M [= (Na + K + 2Ca)/(Al·Si)] (cation ratios) and G [= (3·Al2O3 + SiO2)/(Na2O + K2O + CaO + MgO + FeO)] (molar proportions) represent the melt composition. The errors are at one sigma, and T is the temperature in Kelvin. Before applying these models to natural rocks, it is necessary to ensure that the zircon used to date is crystallized from the host magmatic rock. Assessment of the application of both new and old models to natural rocks suggests that model 1 may be the best for magmatic temperature estimates of metaluminous to peraluminous rocks and that model 2 may be the best for estimating magmatic temperatures of alkaline to peralkaline rocks.
On the basis of reprocessing 34 new two-dimensional spliced long sections(20,191 km) in the Tarim Basin, the deep structure features of the Tarim Basin were analyzed through interpreting 30,451 km of two-dimensional seismic data and compiling basic maps. Seismic interpretation and geological analysis conclude that the Nanhua-Sinian strata are a set of rift-depression depositional systems according to their tectonic and depositional features. The rift valley formed in the Nanhua Period, and the transformation became weaker during the late Sinian Period, which eventually turned into depression. From bottom to top, the deposited strata include mafic igneous, tillite, mudstone, and dolomite. Three major depocenters developed inside this basin during the rift stage and are distributed in the eastern Tarim Basin, the Awati area, and the southwestern Tarim Basin. Among them, the rift in the eastern Tarim Basin strikes in the near east-west direction on the plane and coincides with the aeromagnetic anomaly belt. This represents a strong magnetic zone formed by upwelling basic volcanic rock along high, steep normal faults of the Nanhua Period. Controlled by the tectonic background, two types of sedimentary systems were developed in the rift stage and depression stage, showing two types of sequence features in the Sinian depositional stage. The Nanhua System appears as a wedge-shaped formation, with its bottom in unconformable contact with the base. The rifting event has a strong influence on the current tectonic units in the Tarim Basin, and affects the distribution of source rock in the Yuertus Formation and reservoir beds in the Xiaoerbulake Formation in Lower Cambrian, as well as the gypseous cap rock in Middle Cambrian. The distribution features of the rifts have important and realistic significance for determining the direction of oil and gas exploration in the deep strata of the Tarim Basin. Comprehensive analysis suggests that the Tazhong region is the most favorable zone, and the Kalpin-Bachu region is the optimal potential zone for exploring sub-salt oil and gas in deep Cambrian strata. 相似文献
Acta Geotechnica - The aim of this paper is to study the soil vibration response of a pile group induced by train traffic resting on the inclined bedrock condition. A series of model tests on the... 相似文献
Natural Resources Research - In this paper, we developed a novel hybrid model ICA–XGBoost for estimating blast-produced ground vibration in a mine based on extreme gradient boosting (XGBoost)... 相似文献
The interaction between the cryosphere and atmosphere is an essential and extremely sensitive mutual action process on the earth. Due to global warming and the cryospheric melting, more and more attention has been paid to the interaction process between the cryosphere and atmosphere, especially the feedback of the cryosphere change to the atmosphere. A comprehensive review of the studies on the interaction between the cryosphere and atmosphere is conducted from two aspects: (1) effects of climate change on the cryosphere or responses of the cryosphere to climate change; and (2) feedback of the cryosphere change to the climate. The response of the cryosphere to climate change is lagging. Such a lagging and cumulative effect of temperature rise within the cryosphere have resulted in a rapid change in the cryosphere in the 21st century, and its impacts have become more significant. The feedback from cryosphere change on the climate are omnifarious. Among them, the effects of sea ice loss and snow cover change, especially the Arctic sea ice loss and the Northern Hemisphere snow cover change, are the most prominent. The Arctic amplification (AA) associated with sea ice feedback is disturbing , and the feedback generated by the effect of temperature rise on snow properties in the Northern Hemisphere is also of great concern. There are growing evidence of the impact of the Arctic cryosphere melting on mid-latitude weather and climate. Weakened storm troughs, steered jet stream and amplified planetary waves associated with energy propagation become the key to explaining the links between Arctic cryosphere change and atmospheric circulation. There is still a great deal of uncertainty about how cryosphere change affects the weather and climate through different atmospheric circulation processes at different spatial and temporal scales due to observation and simulation problems. 相似文献