松辽盆地北部青一段油页岩地球化学特征及其记录的古湖泊学信息

油页岩地球化学特征及其记录的古湖泊学信息是揭示油页岩成矿富集规律的关键佐证。根据含油率、TOC、岩石热解、元素分析、生物标志化合物检测及有机显微组分分析，精细刻画了松辽盆地北部ZY1井青一段油页岩的地球化学特征，并分析了其记录的古湖泊学信息，探讨了古湖泊对油页岩有机质富集的控制作用。结果表明：青一段发育8层中等偏好品质的油页岩，下部为高品质油页岩富集层段；油页岩的含油率和TOC质量分数相关性极好，处于未熟—低成熟度演化阶段，生烃潜力大；油页岩中含丰富的萜类和甾类化合物，有机质类型主要为Ⅰ型，有机质来源主要为层状藻占优势的湖泊水生生物。地球化学参数指示，青一段下部古湖泊生产力呈现3个低→高的旋回，对应的古湖泊水体盐度呈现为3个半咸水-咸水旋回、古湖泊水体氧化还原性表现为还原-强还原-还原的厌氧环境，其中旋回Ⅱ后期湖泊生产力最高，对应的水体盐度最高、还原性最强。表明湖泊富营养化造成的高湖泊生产力是青一段高品质油页岩有机质富集的物质基础，盐度分层控制下强还原的湖底环境是高品质油页岩有机质富集的良好保存条件。

Geochemical Characteristics and Paleolimnological Information of Oil Shale in 1st Member of Qingshankou Formation in Northern Songliao Basin

The geochemical characteristics and paleolimnological information of oil shale are the key evidence to reveal the rule of metallogeny and enrichment of oil shale. Based on the analyses of TOC, oil yield, rock pyrolysis, element, biomarker compound,and organic maceral, geochemical characteristics of oil shale in the 1^st Member of Qingshankou Formation in Well ZY1 in northern Songliao basin the were refinedly characterized, paleolimnological information recorded by the oil shale was analyzed, then the control effect of paleolake on organic matter enrichment of oil shale was discussed. The results show that there are 8 layers of medium-high quality oil shale in the 1^st Member of Qingshankou Formation, and the high quality oil shale is mainly in the lower part. The TOC of oil shale has good correlation with the oil yield. Seen from the thermal evolution, the oil shale is in the immature-low mature stage with high hydrocarbon potential. Abundant steranes and terpanes are detected from the oil shale samples. The organic matter type of oil shale is mainly Ⅰ, and the main source of organic matter is lake aquatic organisms dominated by lamalginite. The paleolacustrine productivity of the lower part can be divided into three cycles by geochemical parameters, correspondingly the water salinity of paleolake shows three cycles from semi-saline to saline, and the redox property of paleo-lake shows reduction-strong reduction-reduction. And the paleolacustrine productivity of the late cycle Ⅱ is the highest, corresponding to the highest water salinity and the strongest reducibility. It is suggested that the high lake yield caused by lake eutrophication is the material basis of organic matter enrichment of high-quality oil shale in the 1^st Member of Qingshankou Formation, and the strong reduction environment of bottom water controlled by salinity stratification is favorable for the accumulation of organic matter in high-quality oil shale.