The origin of overpressure in 'old' sedimentary basins: an example from the Cooper Basin, Australia

Overpressure in ‘old’ sedimentary basins that have not undergone rapid, recent sedimentation cannot be easily explained using traditional burial‐driven mechanisms. The last significant burial event in the Cooper Basin, Australia, was the Late Cretaceous deposition of the Winton Formation (98.5–90 Ma). Maximum temperature in the basin was attained during the Late Cretaceous, with cooling beginning prior to 75 Ma. Hence, overpressure related to rapid burial or palaeomaximum temperatures (e.g. hydrocarbon generation) must have developed prior to 75 Ma. Retaining overpressure for 75 Ma in ‘old’ basins such as the Cooper Basin requires extremely low seal permeabilities. An alternative explanation is that overpressure in the Cooper Basin has been generated because of an increase in mean stress associated with an increase in horizontal compressive stress since Late Cretaceous times. Structural observations and contemporary stress data indicate that there has been an increase in mean stress of approximately 50 MPa between Late Cretaceous times to that presently measured at 3780 m. The largest measured overpressure in the Cooper Basin is 14.5 MPa at 3780 m in the Kirby 1 well. Hence, disequilibrium compaction driven by increasing mean stress can explain the magnitude of the observed overpressure in the Cooper Basin. Increases in mean stress (tectonic loading) may be a feasible mechanism for overpressure generation in other ‘old’ basins that have undergone a recent increase in horizontal stress (e.g. Anadarko Basin).     

中国春运人口流动网络的富人俱乐部现象与不平衡性分析

基于“百度地图春节人口迁徙大数据”,利用加权网络的富人俱乐部系数和归一化不平衡系数方法,对2015年中国春运期间人口流动网络的富人俱乐部现象和不平衡性进行分析。研究结果表明：中国春运人口流动网络中存在明显的富人俱乐部现象,富人俱乐部城市包括北京、上海、广州、苏州、深圳和东莞,这些城市主导了超过77.66%中国城市的省际人口流动,且与这些城市之间的人口流动多属于不平衡关系,同时俱乐部城市之间、俱乐部城市与一小部分城市之间则属于平衡关系,这种流动格局很容易造成各城市在人口流动网络中的地位分化,严重影响了人口流动网络的公平性和安全性。     

中国城镇土地非均衡扩张路径与治理策略研究

用经济学中的资源配置理论解释城镇土地非均衡扩张,根据城镇土地扩张的机理不同,把城镇土地分为工业用地、居住用地、基础设施用地,并分别考察了其非均衡扩张路径,在此基础上,从"制度环境-政绩目标-政策工具"三方面提出了非均衡扩张的治理策略。结果认为:招商引资过程中竞相以低地价供地导致了工业用地非均衡扩张;对土地财政的过分追逐导致了居住用地非均衡扩张;地方政府为攫取政治晋升资本,大兴城市基础设施建设导致了基础设施用地非均衡扩张;为系统控制城镇土地非均衡扩张,应在"制度环境-政绩目标-政策工具"三个层次上制定相关治理策略。