柴西阿尔金斜坡古近纪和新近纪沉积演化特征

对柴达木盆地西部阿尔金斜坡西起七个泉构造、东至牛鼻子梁构造古近系下干柴沟组下段($E_3 xg^1$)至新近系狮子沟组($N_2 s$)连井剖面沉积体系演化分析表明:①阿尔金斜坡地区从$E_3 xg^1$ 至$N_2 s$ 发育扇三角洲-浊积扇-滨浅湖滩坝沉积体系;②总体上发育一个完整的沉积旋回,$E_3 xg^1$ 沉积早期为退积旋回,中、晚期则主要为进积旋回;③各个沉积体系开始出现进积旋回的时间不一致,其中,月3 井区从E3xg2 沉积中期开始就持续出现进积旋回,而西岔沟构造则在$N_2 s$ 沉积早期才开始出现进积旋回,月1 井区没有出现进积旋回;④牛参1 井区在$N_2$sy 下部至$N_2 s$ 发育退积旋回。阿尔金斜坡区的沉积体系发育与演化特征充分反映了阿尔金断裂带活动的多期性、阶段性、局部性和不同步性。

Characteristics of Sedimentary Evolution of Paleogene and Neogene in Altun Slope in Western Qaidam Basin

The multi-well crossing section's sedimentary system evolvement of Paleogene Xiaganchaigou formation ($E_3 xg^1$) to Neogene Shizigou formation ($N_2 s$) in Altun slope from Qigequan structure in the west to Niubiziliang structure in the east in western Qaidam basin indicates that ①Altun slope area develops fan delta, turbidite fan and shore lake bar deposit system from $E_3 xg^1$ to $N_2 s$; ② it develops an integral sedimentary cycle as a whole, in the early, $E_3 xg^1$ is a retrograding cycle and in the middle and late it is a progradational cycle; ③ the time that the each sedimentary system appears progradational cycle is different, of which Yue-3 well area develops the progradational cycle in the middle of the E3xg2, while Xichagou structure develops the cycle in the early of the $N_2 s$, in Yue-1 well area the cycle does not appear, and ④Niucan-1 well area develops retrograding cycle from the early of the $N_2$sy to the $N_2 s$. The development and evolution characteristics of sedimentary system in Altun slop area fully reflect that the Altun fault activity is of multistage, phase and local properties as well as out-of-step property to the full.