水下火山喷发沉积特征研究进展

发布时间：2018-12-18 16:36

【摘要】：近年来,随着我国开展大量致密油层的基础地质研究工作,越来越多原本被称作含油气的黑色泥岩,被发现其成因与水下火山作用密切相关。然而由于受到矿物粒度细小,与正常陆源搬运成因泥岩难以区分,以及难以开展对现代水下远端沉积物的采集等问题的影响,国内关于水下火山喷发沉积特征的研究明显薄弱。在阅读大量国内外文献基础上,分别叙述了水下火山喷发作用产生的沉积物的破碎、搬运、沉积作用研究进展。并以三塘湖盆地芦草沟组纹层状泥岩与白云岩中的特殊夹层为研究对象,发现:(1)这些夹层中的矿物成分成熟度低,磨圆差,多呈自形晶体或鸡骨状,显示火山物质来源。(2)夹层呈纹层状和薄层状2类;前者底部具冲刷层,内部具正粒序,且颗粒多具有平行层理的定向性,显示侧向牵引流沉积作用;后者呈混杂堆积,无明显内部结构,显示高密度碎屑流沉积作用。(3)夹层在层序上往往具有局部性和重复性,代表火山脉动式喷发沉积。认为这些夹层可能由水下火山—热液喷发沉积作用形成。最后,对内碎屑、陆源碎屑以及深源碎屑,水下喷发与陆表喷发区别,以及水下喷发沉积岩命名3个问题展开讨论。并建议以宏观微观相结合、超微观岩矿学观察、重视与火山相关的热液喷流沉积作用、与多学科交叉研究4个方面为今后的研究方法与方向。
[Abstract]:In recent years, with the development of a large number of basic geological research work in China, more and more black mudstone, which was originally called oil and gas, has been found to be closely related to underwater volcanism. However, due to the small size of minerals, difficult to distinguish from the normal continental source transport genetic mudstone, and difficult to carry out the collection of modern distal underwater sediments, the study on the characteristics of underwater volcanic eruption deposition is obviously weak in China. On the basis of reading a large number of literatures at home and abroad, this paper describes the research progress of sediment fragmentation, transport and sedimentation caused by underwater volcanic eruption. Taking the special intercalation between lamellar mudstone and dolomite of Lucaogou formation in Santanghu Basin as the research object, it is found that: (1) the mineral composition of these interlayers is low in maturity, poor in grinding round, and mostly in the shape of self-shaped crystal or chicken bone. The source of volcanic material is shown. (2) the intercalation is of lamellar and thin-layer type; The former has a scour layer at the bottom and a positive grain sequence in the interior, and most of the particles have the orientation of parallel bedding, which shows the lateral traction flow deposition. The latter shows mixed accumulation and no obvious internal structure, indicating high-density clastic flow deposition. (3) intercalation is often localized and reproducible in sequence, representing volcanic pulsating eruption deposition. It is suggested that these intercalations may be formed by underwater volcanic-hydrothermal eruption deposition. Finally, the paper discusses three problems: internal clastic, continental clastic and deep-source clastic, underwater eruption and surface eruption, and the naming of underwater eruption sedimentary rocks. It is suggested that the research methods and directions in the future should be the combination of macro and micro, ultramicro petrology observation, emphasis on hydrothermal jet deposition related to volcanoes, and interdisciplinary research.
【作者单位】：大陆动力学国家重点实验室西北大学地质系;Geology
【基金】：国家自然科学基金项目“二叠系纹层状微生物白云岩研究——以新疆准噶尔盆地东部为例”(编号:41572086)和“新疆北东部三塘湖地区二叠纪地幔热液喷流沉积及其形成机理”(编号:41272116)资助~~
【分类号】：P317;P618.13

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