检索结果-南通市图书馆

Sequence Stratigraphy of the desert system: A Case Study of the Lower Cretaceous in the Kuqa Basin in Xinjiang, Northwestern China

引用

Acta Geologica Sinica(English Edition) 2004年第3期78卷 744-755页

作者： MEIMingxiang YUBingsong JINWeiguang SchoolofEarthSciencesandNaturalResources ChinaUniversityofGeosciencesBeijing100083

The Lower Cretaceous strata in the Kuqa Basin in Xinjiang are marked by a set of arid red beds. Several types of sedimentary fades can be identified in this set of arid red beds: mudstones of the plaza and intracontinental sebkha, aeolian sandstones, sandy conglomerates of the intermittent river, conglomerates of the pluvial fan, etc. These types of sedimentary facies constitute a typical desert system. Therefore, the Cretaceous strata in the Kuqa Basin provide a favorable condition for studies of sequence stratigraphic divisions of the desert system. With the rise and fall of the base level of the sedimentary basin, cyclicity is clearly revealed in stratigraphic records, which helps the identification of the third-order sequences. Based on the cyclicity in stratigraphic records, 5 third-order sequences can be found in the strata of the Early Cretaceous in the Kuqa Basin. These sequences comprise a second-order tectonic sequence. The primary feature of these third-order sequences is of an upward-fining sedimentary succession formed by a succession of 'coarse sediments of the alluvial system-fine sediments of the lake system'. The result of this study shows that aeolian sandstones are the best reservoirs of natural gas in the Cretaceous strata in the Kuqa Basin, and that the Kela-2 gas field is the first large gas field dominated by aeolian sandstone reservoirs in China.

关键词： sequence stratigraphy desert system Cretaceous Kuqa Basin Xinjiang northwestern China

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Effects of Precipitation and Livestock Grazing on Foliage Foraging Ants in a Chihuahuan desert Grassland

引用

Open Journal of Ecology 2021年第1期11卷 52-63页

作者： Yosef Steinberger Walt G. Whitford The Mina and Everard Goodman Faculty of Life Sciences Bar-Ilan University Ramat Gan Israel USDA-ARS Jornada Experimental Range Box 3 JER New Mexico State University Las Cruces NM USA

We examined the relationship between seasonal livestock grazing (late summer and late winter) and the abundance of two ant species, Dorymyrmex insana and Forelius pruniosus, on three types of plants (mesquite shrubs, snakeweed sub-shrubs, and mixed grasses) dominated by black grama (Bouteloua eriopoda). Stocking rates were adjusted to remove 75% of the available forage. Since Chihuahuan desert grasslands are not in transition to shrublands, the grasses and some herbaceous plants are the only available forage. We hypothesized that neither rainfall nor cattle grazing would affect the abundance of these ants on mesquite (Prosipis glandulosa) or snakeweed (Gutierrezia sarothrae). Linear regressions of monsoon rainfall on mesquite (Prosopis glandulosa) produced an r2 nearly equal to that with the annual precipitation. Monsoon rainfall on the evergreen sub-shrub, Gutierrezia sarothrae, resulted in June-July rainfall accounting for 47% - 83% of the variation in densities of D. insana on snakeweed. The number of D. insana was more than double the number of F. pruinosus on grasses, mesquite, and snakeweed. There were significant reductions in the abundance of F. pruinosus on the grass in the grazed plots;each year the plots were grazed. There were no significant effects of grazing on the abundance of either of the ant species sampled from G. sarothrae canopies. There were significantly fewer D. insana on mesquite in summer grazed plots than on P. glandulosa in winter grazed and ungrazed plots in the second and third years of grazing. Pre-grazing effects were compromised by the high annual (more than double) precipitation.

关键词： Grazing Litter Ants desert system

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：