Palaeo-stresses inferred from macro- and microfractures in the Balazuc-1 borehole (GPF Programme); contribution to the tectonic evolution of the Cevennes border of the SE Basin of France
Palaeo-stresses inferred from macro- and microfractures in the Balazuc-1 borehole (GPF Programme); contribution to the tectonic evolution of the Cevennes border of the SE Basin of France
复制标题
根据 Balazuc-1 钻孔中的宏观和微观裂缝推断的古应力（GPF 计划）；
DOI：
10.1016/0264-8172(95)00063-1
复制
发表时间：
1996
影响因子：
4.2
通讯作者：
F. Bergerat
中科院分区：
文献类型：
--
作者：
Pierre Martin;F. Bergerat
Balazuc-1科学井是在法国东南部盆地的Ardèche边缘钻探的，目的是研究构造控制区层状油藏中的流体-岩石相互作用。对1218m至1729.5米深度之间钻孔的定向岩心进行了结构研究；描述和分析了在流体输送过程中可能使用的各种类型的裂缝。碳酸盐、硬石膏和硫化物中矿化的4条大断层和335条小断层和张性条带相交。在井底，其中一个主要断裂带进了三叠纪的接触岩和一个被认为是上古生界的地层；其他断裂导致了下-中三叠统某些单元的减薄。断裂面的微构造研究使描述三叠系和下二叠统沉积岩受其影响的构造幕成为可能。在利古里亚特提斯的背景下讨论的这些幕是：(1)早-中三叠世的东西向同沉积伸展，导致上古生代和下-中三叠世的序列向东南倾斜；这种伸展一直持续到晚三叠世。(2)利亚斯早期的N-S伸展幕，以水塑型断裂为特征，可能是伸展应力场局部变化的结果。(3)乌泽尔断裂的主要活动时期，从洛萨林期(华夏晚期)持续到巴吞纪早期，下倾超过1000m。不可能计算出这一时期的应力张量，因为在井眼所经过的下部地块没有发育次级断层系统。(4)约N-S伸展，可能是侏罗纪末至早白垩世，在此期间，Rhaetian和Hetangian矿床中形成了张性裂隙、碳酸盐矿化和黄铁矿。(5)三个挤压和/或走滑幕，可归因于新生代的比利牛期和阿尔卑斯期。井中未识别出渐新世伸展相。
The Scientific borehole Balazuc-1 was drilled on the Ardèche margin of the SE Basin of France for the purpose of studying fluid-rock interactions in stratiform reservoirs in a tectonically controlled area. A structural study was made of oriented cores from the drill hole between the depths of 1218 and 1729.5 m; the various types of fracture that could have been used during fluid transfers have been described and analysed. Four major faults and 335 minor faults and tension gashes mineralized in carbonates, anhydrite and sulphides were intersected. At the bottom of the hole, one of the major faults brings into contact rocks of Triassic age and a formation attributed to the Upper Palaeozoic; the other faults have caused thinning of certain units of the Lower-Middle Triassic. Micro-structural study of the fault planes has enabled characterization of the tectonic episodes by which the Triassic and Lower Liassic sedimentary rocks were affected. These episodes, discussed in the context of the Ligurian Tethys, were: (1) E-W synsedimentary extension during the Early-Middle Triassic that caused tilting to the southeast of the Upper Palaeozoic and Lower-Middle Triassic successions; this continued into the Late Triassic. (2) An episode of N-S extension during the early Lias, characterized by hydroplastic-type faults, probably the result of a local variation of the stress-field in a trans-tensional regime. (3) The major period of activity on the Uzer fault, with downthrow of more than 1000 m, that continued from the Lotharingian (Late Sinemurian) to the Early Bathonian. It was not possible to calculate the stress tensor for this period, because no secondary fault system developed in the lower block traversed by the borehole. Brittle deformation at this time seems to have been concentrated on the major structures., (4) Approximately N-S extension, possibly end-Jurassic to Earliest Cretaceous, during which the tension gashes, mineralized in carbonates, and pyrite were formed in the Rhaetian and Hettangian deposits. (5) Three compressive and/or strike-slip episodes attributed to the Cenozoic Pyrenean and Alpine phases of deformation. The Oligocene extensional phase was not recognized in the borehole.