Lithofacies characteristics, depositional architecture (facies tracts and depositional sequences), stable isotopes (δ¹⁸O and δ¹³C), and ⁸⁷Sr/⁸⁶Sr ratios were analysed from the Aruma Formation at the Khashm Buwaibiyat section (north‐east Riyadh, Saudi Arabia). The Aruma Formation consists of three formal members (base to top), Khanasir, Hajajah, and Lina members. Based on ⁸⁷Sr/⁸⁶Sr and δ¹³C data, the lower age of the regionally distributed Aruma Formation (Khanasir Member) is now proposed as Late Campanian. This age assignment is supported by the identification of a distinct δ¹³C negative excursion (=Epsilon Event; Upper Campanian), and a globally conformable range of ⁸⁷Sr/⁸⁶Sr values (0.707604–0.707703). Additionally, a review of previous fauna (ammonites and nannofossils) also favours this age assignment. The ⁸⁷Sr/⁸⁶Sr values (0.707817–0.707848) from the upper part of the Hajajah Member reflects a Late Maastrichtian signature as also noted by the presence of a long‐term δ¹³C decrease. Additionally, based on lithofacies and depositional architecture for the Aruma Formation, nine facies types are identified. These are grouped into four facies associations (restricted peritidal, lagoon inner ramp, shoal transgressive lag, and coral reefs), reflecting four third‐order depositional sequences (transgression–regression cycles). These reflect strong influence of both eustatic sea‐level rise and regional tectonics (resulting in widespread unconformities and long‐time gaps). The shallowing and deepening of the sea level is inferred using sequence stratigraphy (system tracts) and lithofacies variations. This data suggests a gradual rise in sea level from the Upper Campanian to the Maastrichtian with an intervening fall around the Campanian‐Maastrichtian boundary.

中文翻译：

---

沙特阿拉伯Aruma组的同位素地层学（87Sr / 86Sr，13C）和沉积层序：对欣喜海平面变化的影响

岩相特征，沉积体系结构（相域和沉积序列），稳定的同位素（δ ¹⁸ O和δ ¹³ C），和⁸⁷ SR / ⁸⁶ Sr比值从在Khashm Buwaibiyat部（北-东利雅得的Aruma形成进行分析阿拉伯）。阿鲁玛组由三个正式成员（从下到上），卡纳西尔，哈贾杰和莉娜成员组成。基于⁸⁷的Sr / ⁸⁶ Sr和δ ^13个C数据，所述区域分布Aruma组（Khanasir会员）的低年龄现在被提议为晚坎潘。这个年龄段的分配是由不同δ鉴定支持¹³C负偏移（= Epsilon事件；上坎皮安），全局范围为⁸⁷ Sr / ⁸⁶ Sr（0.707604–0.707703）。此外，对以前的动物区系（菊石和纳米化石）的回顾也有利于这种年龄分配。在⁸⁷ SR / ⁸⁶从Hajajah构件的上部分的Sr值（0.707817-0.707848）反映一晚马斯特里赫特签名也由一个长期存在δ注意到¹³C降低。此外，根据Aruma组的岩相和沉积构造，确定了9种相类型。这些被划分为四个相联系（受限制的围岩期，泻湖内斜坡，浅滩海侵滞后和珊瑚礁），反映了四个三阶沉积序列（海侵—回归循环）。这些反映了欣喜的海平面上升和区域构造的强烈影响（导致广泛的不整合面和长期的空白）。使用层序地层学（系统域）和岩相变化来推断海平面的变浅和加深。这些数据表明，海平面从上坎帕尼至马斯特里赫特逐渐升高，而在坎帕尼-马斯特里赫特边界附近出现了下降。