Graptolites have been collected from sections through Lower Ordovician strata in northern Iran. At the Saluk Mountains, in the Kopet–Dagh region, mudrocks yielded fragmentary tubaria of Rhabdinopora sp. cf. R. flabelliformis, indicating the presence of lower Tremadocian strata there; stratigraphically, they lie between two limestone beds with the euconodont Cordylodus lindstromi. At Simeh–Kuh in the eastern Alborz Mountains (Semnan Province), upper Tremadocian – lower Floian strata include laminated dark mudstones that contain restricted graptolite faunas, mainly of small declined didymograptids; these are thought to represent incursions of plankton during periods of marine highstands. The lower major flooding surface in Simeh–Kuh coincides with an invasion of the graptolite biofacies and an incursion of Hunnegraptus? sp.; the second major flooding surface is associated with an incursion of Baltograptus geometricus. They were most probably synchronous with those in the lower part of the Hunnegraptus copiosus Biozone and at the base of the Cymatograptus protobalticus Biozone in the of the Tøyen Shale Formation succession of Västergötland, Scandinavia, suggesting that observed characters of sedimentation were eustatically controlled.

中文翻译：

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伊朗厄尔布尔士东部的第一个早奥陶纪笔石和海洋入侵

笔石是从伊朗北部下奥陶统地层的剖面中收集的。在 Kopet-Dagh 地区的 Saluk 山脉，泥岩产生了弹头目sp。参看。R.flabelliformis, 表明那里存在较低的 Tremadocian 地层; 在地层上，它们位于两个石灰岩床之间，有真牙形冬虫夏草. 在厄尔布尔士山脉东部（塞姆南省）的 Simeh-Kuh，上 Tremadocian - 下 Floian 地层包括层状深色泥岩，其中包含受限的笔石动物群，主要是小型下降的 didymograptids；这些被认为代表了海洋高位时期浮游生物的入侵。Simeh-Kuh 较低的主要洪水面与笔石生物相的侵入和猎手? sp.; 第二个主要泛滥表面与入侵有关几何海象. 他们很可能与那些在下半部分的人同步鲶鱼生物区和在底部原巴尔提鲛斯堪的纳维亚的 Västergötland 的 Tøyen 页岩组演替中的生物带，表明观察到的沉积特征受到了海浪控制。