Abstract In the Alpstein massif of north-eastern Switzerland, a complete succession uppermost Hauterivian to Barremian condensed hemipelagic sediments crops out. This is known as Tierwis Formation, comprising in ascending order, Altmann and Drusberg members. The sedimentary bears number fossiliferous glauconite- or phosphate-rich beds. A large newly discovered ammonites from these key beds seve...

The systematics of ammonoids are complicated by their large degree intraspecies variation, which complicates a stable validation species. Aegocrioceras is heteromorph ammonite from the Lower Saxony Basin in Hauterivian Boreal, and prime example genus with an unstable internal systematic external relationship to other ammonoids. Here, we use quantitative morphometrics on species assemblage colle...

The investigated section cropping out in Kuh-e-Banesh, Zagros basin (southern Iran) is represented by limestone, Cherty beds and marllevels bearing abundant Planktonic foraminifers, radiolarian microfaunas, and ammonite imprints. For the first time, well to moderatelypreserved forms of Planktonic foraminifera have been extracted from black shale and marls levels. Extracted biota was studied wit...

—Marshall (1995) used the distribution of the endpoints of 50% range extensions added to the stratigraphic ranges of individual taxa to bracket the position of an extinction boundary. Here we describe two improvements to Marshall’s method. First, we show that more precise estimates of the position of such a boundary may be obtained using range extensions with confidence levels of less than 50% ...

Abstract Due to the growing need for hydrocarbons and limited conventional resources, paying attention unconventional oil gas resources is essential. The upper Jurassic-Lower Cretaceous in western southwestern Iran contains most crucial source rocks of Zagros sedimentary basin. One richest shaly Garau Formation. Owing geochemical geological characteristics, Formation, with Neocomian Coniacian a...