磷灰石裂变径迹在滨北地区热史研究中的应用  

Application of apatite fission track in the research of thermal evolution history in Binbei area

作　　者：姜继玉[1] 姜艳春[2] 王剑峰[3] 范秀杰[3] 

机构地区：[1]大庆石油学院电子科学学院,黑龙江大庆163318 [2]大庆油田责任有限公司第一采油厂,黑龙江大庆163001 [3]大庆油田技术培训中心,黑龙江大庆163255

出　　处：《大庆石油学院学报》2009年第3期43-48,共6页Journal of Daqing Petroleum Institute

摘　　要：分析磷灰石裂变径迹视年龄、平均长度与深度关系,认为滨北地区退火带深度为1 000～2 000 m,对应古地温为70～125℃,退火带之内的平均古地温梯度应为5.5℃/100m.单颗粒年龄分析表明,在20～30 Ma和40～50 Ma经历过2次明显的冷却过程,最高古地温出现在白垩纪末期,早第三纪之后开始降温.利用封闭径迹长度分布正演模拟模型(扇形模型),结合古剥蚀史和古热流史对古热史进行模拟,认为古地温梯度在晚白垩世为5.5～5.7℃/100m,第三纪以来逐渐降低,到晚第三纪达到3.2～3.7℃/100m.滨北地区有机质热演化在白垩纪末达到最高峰.早第三系之后的持续抬升剥蚀和大地热流值衰减降温使热演化作用过程"冷冻",生烃作用停止.Based on the analysis of the apparent ages, the relation between the average length and the buried depth, results show that the annealing zone distributes between 1 000 m to 2 000 m and the corresponding paleotemperature was about 70~125 ℃, so the average geothermal gradient in the research area should be 5.5 ℃/100m.The single sample age shows that two cooling events occurred obviously , and the paleo-temperature reached the peak at the end of Cretraceous, while the temperature began to decrease after Tertiary; with the erosion history and paleoheat flow history, the thermal history was simulated by means of a forward model (fanning annealing model) and the results indicate that the geothermal gradient was about 5.5~5.7 ℃/100m. It began to decrease since Tertiary and reached 3.2~3.7 ℃/100m at late Tertiary. The thermal evolution of organic matters in the research area got to the peak at the end of Cretraceous,but it was frozen by continuous uplift and erosion and the decrease of the Terrestrial heat flow after Tertiary, which made hydrocarbon generation stop.

关 键 词：磷灰石 裂变径迹 滨北地区 热演化史 白垩纪末期 

分 类 号：TE122[石油与天然气工程—油气勘探]