辽河油田两个斑岩侵入体裂缝特征对比研究

辽河油田东部凹陷中段的黄沙坨和欧利坨子斑岩体相距不到10 km,均侵位于始新统沙河三段下部的碳质泥岩烃源层.地球化学分析表明,两岩体均为粗面斑岩,成分非常一致,很可能在深部相连或来源于同一岩浆房.但两者的储油裂缝系统却迥然不同,欧利坨子岩体发育一套隐爆角砾岩裂缝系统,而黄沙坨岩体则主要发育了火成岩中首次被报道的一套以水平裂缝、波状水平裂缝和剪切裂缝为特征的波状-水平裂缝系统.结合具体地质特征对两类裂缝系统作了对比,并讨论了其形成机制.

Comparative researches of fracture characteristics of two porphyrtic intrusions in the Liaohe basin

The Oulituozi and the Huangshatuo trachyte porphyry intrusions, that are separated less than 10 km apart, occur in the middle segment of the Eastern depression of the Liaohe basin and intrude in the Eocene carbonaceous and argillic hydrocarbon source beds of the third member of the Shahejie formation. Field relationship indicate that they are distinctive in emplacement mechanism from trachytic volcanites in the same area. These two intrusions are lithologically and geochemically comparable to each other, implying that they are likely to represent two branches of a single intrusion at deeper levels or have been derived from a single Eocene magma chamber. However, remarkable differences have been found between these two intrusions. Crypto-explosive breccias are well developed in the Oulitouzi intrusion, whereas the Huangshatuo intrusion is characterized by a fracture system comprising horizontal, sinuate and shear fractures. The comparison has been made of the fractures of these two intrusions in geological features and formation mechanism.