Detailed microfacies analysis and sequence stratigraphic architecture of the Bajocian- mid-Callovian Samana Suk Formation exposed in the Hazara Basin, Lesser Himalaya of Pakistan, were examined. The formation reveals deposition on a carbonate ramp under variable low to high energy environments, such as carbonate mud-flats, lagoon, barrier/shoals, and open-marine setting. The stacking pattern of facies association depicts the change in depositional style in response to sea-level fluctuations. Vertical distribution of recognized facies allows dividing the Bajocian- mid-Callovian strata into one major sequence of second-order hierarchy with superimposed four cycles of third-order genetic sequences (DS1-DS4), bounded above and below by type-one unconformity. The succession comprised of the Bajocian- early Callovian Transgressive System Tract (TST) and early-mid Callovian Highstand System Tract (HST) differentiated by maximum flooding surface. It is reasonable to compare at least Bajocian- early Callovian retrogradational cycle (TST) with long-term global eustatic reconstruction suggesting eustatic change as a primary control on regional shoreline movement. Later, the sea level tends to drop toward the middle of Callovian, forming a prograding Highstand System Tract (HST). These HST deposits record a significant retreat of shoreline toward the termination of mid-Callovian, which ultimately led to regional uniformity above the Samana Suk Formation. This cycle indicates deflection from global sea-level signatures ascribes to regional tectonics in the region. For the first time, this study signifies the importance of regional tectonics overwhelming the global eustatic record of middle Jurassic carbonates in the region.

研究了在巴基斯坦小喜马拉雅山哈扎拉盆地出露的 Bajocian-中-Callovian Samana Suk 组的详细微相分析和层序地层结构。该地层揭示了碳酸盐斜坡沉积在不同的低能量到高能量环境下，例如碳酸盐泥滩、泻湖、屏障/浅滩和开阔的海洋环境。相组合的叠加模式描述了沉积样式随海平面波动的变化。已识别相的垂直分布允许将 Bajocian-mid-Callovian 地层划分为一个二阶层序的主要层序，其中叠加了四个三阶成因层序 (DS1-DS4)，上下界为一类不整合面。该序列包括以最大洪水面区分的 Bajocian-早 Callovian 海侵系统域 (TST) 和早-中期 Callovian 高位系统域 (HST)。至少将 Bajocian-Early Callovian 逆行周期 (TST) 与长期全球浮沉重建进行比较是合理的，这表明浮沉变化是区域海岸线运动的主要控制因素。后来，海平面趋向于向卡洛维安中部下降，形成一个前移的高位系统带（HST）。这些 HST 矿床记录了海岸线向 Callovian 中部终止的显着后退，最终导致 Samana Suk 组上方的区域均匀性。这个周期表明全球海平面特征的偏转归因于该地区的区域构造。首次，