Tectonic movements since the Neogene have been the major developmental and evolutional stages of the latest global crustal deformation and orogenic movements. China is located in a triangular area bounded by the India...Tectonic movements since the Neogene have been the major developmental and evolutional stages of the latest global crustal deformation and orogenic movements. China is located in a triangular area bounded by the Indian landmass, the West Siberian landmass and the Pacific Plate, characterized by relatively active tectonic movements since the Neogene, and in this region, natural gas would have been very easy to dissipate, or difficult to preserve. Therefore, the characteristics of post-Neogene tectonic movements offer important geological factors in researching the formation and preservation of gas reservoirs in China. Summarizing the reservoiring history of gas fields in China, although there are some differences between various basins, they are all affected by the tectonic movements since the Neogene. These movements have certainly caused destruction to the reservoiring and distribution of natural gas in China, which has resulted in a certain dissipation of natural gas in some basins. As a whole, however, they have mainly promoted the reservoiring and accumulation of natural gas: (1) a series of China-type foreland basins have been formed between basins and ridges in western China, which provide favorable conditions for the formation of large and medium gas fields, as well as controlling the finalization of gas reservoirs in the basins; (2) rows and belts of anticlines have been formed in the Sichuan Basin in central China, which have been the major stages of the formation and finalization of gas reservoirs in that basin; the integral and quick rising and lifting, and a further west-dipping in the Ordos Basin have resulted in a further accumulation of natural gas in gas fields from Jingbian to Uxin; (3) in eastern China, the Bohai movement in the late Pliocene has provided favorable geological conditions for lately-formed gas reservoirs in the Bohai Sea area mainly composed of the Bozhong depression; and it also resulted in secondary hydrocarbon generation and formation of secondary gas reservoirs in other basins, as well as the formation of many carbon dioxide gas fields of inorganic origin; (4) in the offshore area, it promoted not only the formation of gas reservoirs of organic origin, but also the formation of inorganic origin non-hydrocarbon gas reservoirs, as well as the organic and inorganic natural gas of mixed origin, which resulted in the relatively complicated characteristics of gas reservoirs in the area. In short, tectonic movements activated since the Neogene resulted in a reservoiring model mainly characterized by late and superlate hydrocarbon generation and accumulation. These events provide an important geological stage that should not be neglected when studying the formation of gas reservoirs in China.展开更多
Most cities around the world, including Abuja Municipal are being faced with an undesirable increased in air temperature. This is indicated by an increase in non-porous, non-evaporating, highly thermal conductive surf...Most cities around the world, including Abuja Municipal are being faced with an undesirable increased in air temperature. This is indicated by an increase in non-porous, non-evaporating, highly thermal conductive surfaces such as concrete and asphalt, which has replaced the vegetation biomass resulting to the formation of urban heat island. There is an increasing need for studies on the changing trend of UHI intensity in cities. This research employed geospatial techniques to determine the urban heat island intensity in Abuja Municipal. Temperature characteristics over twenty selected rural and urban locations in Abuja, FCT were derived from the satellite image of 1986, 2001 and 2016 using the “Extract Multi Values to Point” tool in ArcGIS 10.4. These transects pass over various landscapes with different environmental settings, with the aim of understanding the factors shaping the city’s thermal landscape. The intervals of +15 years were deliberately chosen to ensure uniformity between the datasets. The results of this analysis indicate that UHII has been increasing, from 1986-2016, giving credence to the results of the spatial and temporal analysis of the land surface temperature, indicating the development phases had hit full stride. The different periods under study (1986, 2001 and 2016) were also tested using the student “t” test to determine the significant difference in the land surface temperature values to acknowledge the presence of a substantial urban heat island within the study area. The result reveals the calculated “t” values of 2.50, 3.34, 5.57 of 1986, 2001 and 2016 respectively, are higher than the critical value of “t” at 0.05 being 1.73, thus, revealing the temperature differences between the urban and rural stations to be highly significant, indicating the presence of a strong urban heat island. Also, a slide difference in the temperature was observed with the Rubuchi and Karmajiji rural areas having higher temperature readings than their counterparts in the urban areas, Asokoro and Garki, with readings of <span style="white-space:nowrap;">−</span>0.4<span style="white-space:nowrap;">°</span>C and <span style="white-space:nowrap;">−</span>1.3<span style="white-space:nowrap;">°</span>C. Since effectiveness of a surface in reducing daytime urban air temperatures depends strongly on the amount of heating avoided, the study recommends preserving and replicating greenery, light coloured facades as measures to reduce the effects of urban heat island.展开更多
文摘Tectonic movements since the Neogene have been the major developmental and evolutional stages of the latest global crustal deformation and orogenic movements. China is located in a triangular area bounded by the Indian landmass, the West Siberian landmass and the Pacific Plate, characterized by relatively active tectonic movements since the Neogene, and in this region, natural gas would have been very easy to dissipate, or difficult to preserve. Therefore, the characteristics of post-Neogene tectonic movements offer important geological factors in researching the formation and preservation of gas reservoirs in China. Summarizing the reservoiring history of gas fields in China, although there are some differences between various basins, they are all affected by the tectonic movements since the Neogene. These movements have certainly caused destruction to the reservoiring and distribution of natural gas in China, which has resulted in a certain dissipation of natural gas in some basins. As a whole, however, they have mainly promoted the reservoiring and accumulation of natural gas: (1) a series of China-type foreland basins have been formed between basins and ridges in western China, which provide favorable conditions for the formation of large and medium gas fields, as well as controlling the finalization of gas reservoirs in the basins; (2) rows and belts of anticlines have been formed in the Sichuan Basin in central China, which have been the major stages of the formation and finalization of gas reservoirs in that basin; the integral and quick rising and lifting, and a further west-dipping in the Ordos Basin have resulted in a further accumulation of natural gas in gas fields from Jingbian to Uxin; (3) in eastern China, the Bohai movement in the late Pliocene has provided favorable geological conditions for lately-formed gas reservoirs in the Bohai Sea area mainly composed of the Bozhong depression; and it also resulted in secondary hydrocarbon generation and formation of secondary gas reservoirs in other basins, as well as the formation of many carbon dioxide gas fields of inorganic origin; (4) in the offshore area, it promoted not only the formation of gas reservoirs of organic origin, but also the formation of inorganic origin non-hydrocarbon gas reservoirs, as well as the organic and inorganic natural gas of mixed origin, which resulted in the relatively complicated characteristics of gas reservoirs in the area. In short, tectonic movements activated since the Neogene resulted in a reservoiring model mainly characterized by late and superlate hydrocarbon generation and accumulation. These events provide an important geological stage that should not be neglected when studying the formation of gas reservoirs in China.
文摘Most cities around the world, including Abuja Municipal are being faced with an undesirable increased in air temperature. This is indicated by an increase in non-porous, non-evaporating, highly thermal conductive surfaces such as concrete and asphalt, which has replaced the vegetation biomass resulting to the formation of urban heat island. There is an increasing need for studies on the changing trend of UHI intensity in cities. This research employed geospatial techniques to determine the urban heat island intensity in Abuja Municipal. Temperature characteristics over twenty selected rural and urban locations in Abuja, FCT were derived from the satellite image of 1986, 2001 and 2016 using the “Extract Multi Values to Point” tool in ArcGIS 10.4. These transects pass over various landscapes with different environmental settings, with the aim of understanding the factors shaping the city’s thermal landscape. The intervals of +15 years were deliberately chosen to ensure uniformity between the datasets. The results of this analysis indicate that UHII has been increasing, from 1986-2016, giving credence to the results of the spatial and temporal analysis of the land surface temperature, indicating the development phases had hit full stride. The different periods under study (1986, 2001 and 2016) were also tested using the student “t” test to determine the significant difference in the land surface temperature values to acknowledge the presence of a substantial urban heat island within the study area. The result reveals the calculated “t” values of 2.50, 3.34, 5.57 of 1986, 2001 and 2016 respectively, are higher than the critical value of “t” at 0.05 being 1.73, thus, revealing the temperature differences between the urban and rural stations to be highly significant, indicating the presence of a strong urban heat island. Also, a slide difference in the temperature was observed with the Rubuchi and Karmajiji rural areas having higher temperature readings than their counterparts in the urban areas, Asokoro and Garki, with readings of <span style="white-space:nowrap;">−</span>0.4<span style="white-space:nowrap;">°</span>C and <span style="white-space:nowrap;">−</span>1.3<span style="white-space:nowrap;">°</span>C. Since effectiveness of a surface in reducing daytime urban air temperatures depends strongly on the amount of heating avoided, the study recommends preserving and replicating greenery, light coloured facades as measures to reduce the effects of urban heat island.
