نتایج جستجو برای: lower paleozoic
تعداد نتایج: 693427 فیلتر نتایج به سال:
The Central Balkan Zone belongs to the north-vergent fold-and-thrust belt of Alpine orogen. In this zone, pre-Permian low-grade rocks, metamorphosed during Variscan orogeny, were later reworked at two main stages compressional tectonics. Several tectono-stratigraphic subdivisions these metamorphic rocks previously presented, based on a purely stratigraphic approach in absence detailed structura...
Circular-parabolic pits occur commonly on the endoskeletal remains of certain Paleozoic crinoids. Detailed study of several hundred specimens, representing about 30 pelmatozoan species from the Upper Silurian Rochester Shale of New York and Ontario, reveals that such pits occur exclusively in seven species of crinoids. Furthermore, there are consistent differences in the morphology and orientat...
The genus Lycopodites, which encompasses the herbaceous forms of the lycopsids, presents broad time and spacial distribution during the Paleozoic in the Northern Hemisphere, with its initial records dating from the European Devonian. As to Gondwanan Paleozoic, to this moment, only Lycopodites amazonica Dolianiti had been reported for the Amazonian Middle Devonian (Curuá Group). Thus, the specim...
To investigate the characteristics of Paleozoic magmatism in Central Iran, the volcanic rocks from some area like Abyane, Zefreh, Bagherabad and Dalmeh have been studied and have been compared to another area like Jahagh and Polekhavand. The volcanic horizon occurred as lava flows with massive and pillow structures and intermittent with several sediments layers such as sandstones and carbonate...
The Tian Shan range offers a natural laboratory to study orogenic processes. Most of the previous studies focused on either the Paleozoic evolution of the range or its Cenozoic intracontinental evolution linked with the India-Asia collision. In this study, detailed field investigations on the relationship between sedimentary cover and basement constrain the Mesozoic evolution of the northern Ti...
نظر به اهمیت کنودونتها در تقسیمات چینهنگاری پالئوزوئیک و گسترش قابل توجه نهشتههای دونین پسین و کربونیفر پیشین در منطقه کرمان سه برش چینهشناسی (حور، هوتک و شمس آباد) در شمال استان کرمان انتخاب و بویژه بر اساس کنودونتها و بقایای ماهیان مورد مطالعه قرار گرفتند. مجموعه کنودونتهای بدست آمده از برش حور شامل 20 گونه متعلق به دو جنس polygnathus و icriodus بوده و سنی معادل فرازنین پسین را نشان می...
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