A Unique Occurrence of a Psammosteid Heterostracan on the Peri-gondwanan Shelf in the Lower/middle Devonian Boundary Marine Deposits
نویسندگان
چکیده
A rare psammosteid heterostracan (Agnatha) occurrence in the Devonian of the Prague Basin is indicative of a dry land influence in the regional palaeogeography. This argument is strongly supported by the appearance of vascular plants, but the studied vertebrates allow us to presume a local brackish water environment. These conditions are considered to be related to a supposed land in the vicinity of the preserved relic of Devonian rocks in the Teplá-Barrandian unit. Such unique conditions were not repeated in the area despite the increasing extent of continental environment related to the rising Variscan Orogeny.
منابع مشابه
Carbon isotope (N13C) stratigraphy across the Silurian^Devonian transition in North America: evidence for a perturbation of the global carbon cycle
Carbon isotope (N13C) analyses of marine carbonates spanning the Silurian^Devonian transition are compared from three richly fossiliferous, well-dated sequences in North America. The three sections, in the central Appalachian Mountains (West Virginia), Great Basin (Nevada), and the southern Mid-continent (Oklahoma), reveal positive N13C shifts beginning in the late Pridoli and reaching peak val...
متن کاملTectonosedimentary evolution of the basins in Central Alborz, Iran
Evidence of at least ten different tectonic- controlled sedimentary basins can be recognized in the central part of the Alborz Mountains in the Middle part of the Alpine-Himalayan belt. They formed from Neoprotrozoic to recent time as the results of the relative plate motion in southwest of Asia in Tethyan realm. The basins include: (1) Prototethys Late Neo-Proterozoic to Early Ordovician epi-c...
متن کاملUPPER DEVONIAN ACRITARCHS AND MIOSPORES FROM THE GEIRUD FORMATION IN CENTRAL ALBORZ RANGE, NORTHERN IRAN
The Geirud Formation consists mainly of clastic sediments which are interbedded with limestone stringers. This rock unit is well-exposed along the Central Alborz Range in northern Iran. The Geirud Formation rests unconformably on the Mila Formation (Upper Cambrian) and is conformably overlain by the Mobarak Formation (Lower Carboniferous). This study was undertaken to determine the geologi...
متن کاملBiostratigraphy of Oligo-Miocene marine deposits of Central Iran basin based on calcareous nannoplanktons
Background and Objectives: ?????? Methods: ?????? Findings: ?????? Conclusion: ????? The present study is the first study aimed at biostratigraphy based on calcareous nannoplankton that has been performed on all succession exposed from the Oligo-Miocene marine deposits (members a to f of the Qom Formation). The studied deposits are located in the middle part of the Central Iran Zone and m...
متن کاملFacies, sedimentary environments and sequence stratigraphy of Cretaceous deposits in the northwest of Azerbaijan, Iran
The Cretaceous deposits in Morakan, located in the northeast of Khoy, a town in western Azerbaijan province, Iran, are primarily made up of carbonate rocks. These deposits, which are of 717 meters thick, lie on the clastic facies of Jurassic and are covered with beneath the pelagic beds of the Upper Cretaceous. To investigate the facies, sedimentary environment and sequential stratigraphy of th...
متن کامل