This study presents the first record of stable carbon and oxygen isotopes of well-preserved belemnites and bulk sediment from the Upper Jurassic pelagic carbonates of the Ouarsenis Mountains (northwestern Algeria), which were deposited at the southern margin of the Tethys ocean. Cathodoluminescence and scanning electron microscopy was used to eliminate potentially diagenetically altered specimens (brachiopods, aptychi, and some belemnites). Ultimately, 55 belemnite specimens were used to reconstruct water temperatures for the Middle Oxfordian to the Early Tithonian. Their δ¹⁸O_carb values ranged from −0.35‰ to −3.88‰, suggesting warm and mostly stable temperature conditions during the Late Jurassic. Using a δ¹⁸O_sea value of 0‰ for the tropical palaeolatitude of 15–20°N, the δ¹⁸O_carb values of the well-preserved belemnite rostra translate into average temperatures of 27.8 °C in the Middle Oxfordian (Gregoryceras transversarium Zone), 27.0 to 27.5 °C in the Late Oxfordian (Epipeltoceras bimmamatum and Idoceras planula zones, respectively), 26.2 °C in the Early Kimmeridgian, and 27.3 °C in the Early Tithonian (Hybonoticeras hybonotum Zone).

这项研究提供了保存完好的贝伦犬类和大量沉积物的稳定碳和氧同位素的第一个记录，这些沉积物来自于Oethsenis山（阿尔及利亚西北部）的上侏罗统上层碳酸盐岩，沉积在特提斯海洋的南缘。阴极发光和扫描电子显微镜用于消除潜在的介电改变的标本（腕足类，aptychi和一些贝类）。最终，使用55个贝莱石标本重建了牛津中部至提通早期的水温。他们δ ¹⁸ Ø_{碳水化合物}值介于-0.35‰〜-3.88‰，晚侏罗世期间暗示温暖和基本稳定的温度条件。使用δ ¹⁸ Ø_海为15-20°N热带古纬度的0‰值时，δ ¹⁸ ö_{碳水化合物}保存完好的箭石的值罗斯特拉翻译成在中东牛津阶的27.8℃的平均温度（Gregoryceras transversarium区），27.0〜27.5° C在牛津晚期（分别为Epipeltoceras bimmamatum和Idoceras planula带），早期Kimmeridgian中为26.2°C和Tithonian早期（Hybonoticeras hybonotum带）中为27.3°C 。