Oxygen and carbon isotope ratios of calcareous tests of foraminifera can serve as a tool for reconstructing seawater temperatures and bioproductivity. The foraminiferal isotope studies are, however, largely limited to Neogene, Paleogene and Cretaceous strata. In the current study are presented δ¹⁸O and δ¹³C values of well-preserved Jurassic representatives of different groups of benthic foraminifera: low-Mg calcite Lenticulina (Lagenata), high-Mg calcite Paleomiliolina (Miliolida, Tubothalamea) and aragonite Epistomina (Robertinida, Globothalamea) derived from clay deposits of Poland. Moreover, it provides the detailed comparison of isotopic data of Jurassic foraminifera with those of various co-occurring macrofossils (belemnite rostra, ammonite and bivalve shells). Our study and comparative data substantiate the existence of the offset of Lenticulina's δ¹⁸O values from isotope equilibrium of ca. 1‰, which seems to be relatively constant over geological time. This value may be used for calculation of ancient water temperatures from oxygen isotope ratios of well-preserved specimens of this very common and widespread Jurassic foraminiferal taxon. δ¹⁸O values of Epistomina and δ¹³C values of all studied foraminifera are significantly biased from isotope equilibrium.

有孔虫钙质测试的氧和碳同位素比可以作为重建海水温度和生物生产力的工具。然而，有孔虫同位素研究主要限于新近纪、古近纪和白垩纪地层。在目前的研究中，我们展示了保存完好的侏罗纪不同种类底栖有孔虫代表的δ ¹⁸ O 和 δ ¹³ C 值：低镁方解石Lenticulina (Lagenata)、高镁方解石Paleomiliolina (Miliolida, Tubothalamea) 和文石Epistomina(Robertinida, Globothalamea) 来自波兰的粘土矿床。此外，它还提供了侏罗纪有孔虫的同位素数据与各种共生大型化石（箭石、菊石和双壳类贝壳）的同位素数据的详细比较。我们的研究和比较数据证实了Lenticulina的 δ ¹⁸ O 值与约的同位素平衡存在偏移。1‰，在地质时期似乎相对恒定。该值可用于根据这种非常常见和广泛分布的侏罗纪有孔虫类群的保存完好标本的氧同位素比率计算古代水温。Epistomina和 δ ^{13 的}δ ¹⁸ O 值所有研究的有孔虫的 C 值显着偏离同位素平衡。