Search results for "Devonian"
showing 10 items of 77 documents
The earliest evidence of host-parasite interactions in vertebrates
2009
Luk s evics, E., Lebedev, O. A., Mark-Kurik, E. and Karataj u te-Talimaa, V. 2009. The earliest evidence of host‐parasite interactions in vertebrates. — Acta Zoologica (Stockholm) 90 (Suppl. 1): 335‐343 Traces of parasite action have been discovered in the Middle‐Upper Devonian fish from Estonia, Latvia and European Russia. Such traces are known in heterostracan Psammolepis venyukovi , antiarchs Asterolepis radiata and Bothriolepis ciecere , sarcopterygians Holoptychius sp., Ventalepis ketleriensis and Eusthenodon sp. nov. The traces include evidence of parasitic fixation and penetration as well as dwelling traces. Pathologies are developed as (1) round fossulae on the external surface of b…
Upper Givetian and Frasnian (Middle and Upper Devonian) conodonts from Ampriú (Aragonian Pyrenees, Spain): global correlations and palaeogeographic r…
2012
This report describes for the first time a part of the Middle and Upper Devonian conodont sequence of the Sierra Negra Subfacies in the Aragonian Pyrenees (Spain), establishing the basis for further sound correlations both across the distinct Pyrenean facies and subfacies and on other relevant world areas. The description of 20 conodont taxa and their stratigraphical distribution permits recognition of two separate time intervals. The older one corresponds to the lower Upper Givetian (Middle Devonian), hermanni to crista- tus ectypus zones. The younger interval is uppermost Lower Frasnian to lower Middle Frasnian (Upper Devonian) and is equivalent to MN4-MN6 zones. The combination of litho-…
A long-snouted late Eifelian arthrodire from Aragon (Spain)
2021
Carolowilhelmina geognostica Carls, 1995 is a large arthrodire (Placodermi) from the Tortodus kockelianus Conodont Zone, late Eifelian, in the Eastern Iberian Cordillera in southern Aragon. The somewhat incomplete but articulated skull is preserved, showing a long tubular rostral plate, very small postnasal plates, low toothless inferognathals, and a small, slender and flat parasphenoid. Supraorbital and central sensory lines meet their antimeres at the midline of the skull, forming a straight double line. Lines along the ventral surface of the rostral plate probably belong to the suborbital branches of the infraorbital sensory lines. The combination of characters of Carolowilhelmina points…
Pēdu fosiliju kompleksi galvenā devona lauka Franas stāva nogulumos
2013
ANOTĀCIJA Promocijas darbā analizēts pēdu fosiliju komplekss Franas stāva nogulumos Galvenajā devona laukā. Balsttes uz ievākt un notikt ihnofosiliju matriālu, tka izveidota sistmātskā ihnoloģija, pēc kuras analīzes nodalītas ihnokompleksu grupas un ihnofācijas. Iegūte dat ļāva papildināt iepriekš pastāvošos priekšstatus par Galvenā devona lauka Franas stāva nogulumos pārstāvēt organismu grupu daudzveidību, intrpretēt faciālo apstākļu mainību un paleoekoloģiskos apstākļus Baltjas devona baseinā Franas laikmetā. Galvenā devona lauka Franas stāva nogulumos dominējošās ihnofācijas norāda uz seklas jūras sedimentācijas vidi un mainīgiem faciālajiem apstākļiem. Pētījumā tka konstatēta ihnofosili…
Zemes dzīļu bagātības Latvijā: DOLOMĪTS
2021
Buklets "Zemes dzīļu bagātības Latvijā: DOLOMĪTS" iepazīstina ar vienu no Latvijas vērtīgākajiem dabas resursiem, tā daudzveidību un tajā atklātajiem interesantajiem minerāliem. Iekļauta informācija par dolomītu pētniecību, nozīmīgākajām mūsdienās izmantojamām dolomīta atradnēm un atšķirīgajiem pielietojuma veidiem. Bukletu ilustrē Latvijas Universitātes Muzeja Ģeoloģijas kolekciju dolomīta paraugu fotogrāfijas.
The Palaeomagnetism of the Permian Rocks of the Black Forest, Germany
1972
Summary Palaeomagnetic measurements made upon Permian samples from the Black Forest, Odenwald and Pfalzerwald (excluding those measurements on samples from the Schopfheim basin) are consistent with those from north-western Europe. The virtual pole based upon 18 sites is 174.9°E. 48.4N. The measurements made on the fine-grained shales and mudstones from the Schopfheim basin are significantly different from the preceding. Since incorrect age assignment, sampling, components of secondary magnetic and tectonic effects can be excluded, the difference is attributed to incomplete removal of the effects of secular variation. The Scharfenstein massif previously regarded as Permian, was found to have…
Morphology, internal structure and genesis of the Burtnieks drumlin field, Northern Vidzeme, Latvia
1997
Abstract The Burtnieks drumlin field is one of the largest in the Baltic countries. It occupies a broad and uneven bedrock macrodepression. The uneven distribution of drumlins is related to the relief of the bedrock surface. Needle-shaped drumlinoids occur in the proximal part of the drumlin field, and they gradually merge into typical drumlin forms downglacier. This morphologic change reflects the differences in their genesis as suggested by internal structure. The cores of drumlins consist mainly of glaciotectonically deformed Pleistocene sediment and, in some places, also weakly cemented, dislocated Middle Devonian sandstone. All of them are folded into linear anticlines trending paralle…
The Devonian Stratigraphic Succession and Evolution of the Baltic Sedimentary Basin
2014
Facies analysis, biostratigraphic and taphonomic studies, a re-evaluation of signatures of worldwide events, and a new mathematical model of the Baltic sedimentary basin (BSB) have together enabled a better understanding to be gained of the development of the Devonian basins in the Baltic area. We have established four stages of basin evolution: (a) remnant basin stage (Lochkovian); (b) shallow epeiric basin stage, with mainly siliciclastic sedimentation (Pragian–early Frasnian); (c) shallow epeiric basin stage, with mainly carbonate sedimentation (Frasnian); and (d) infilling stage of the progressively narrowing shallow epeiric basin, with mixed sedimentation (Famennian).
Results of the DEKORP 1 (BELCORP-DEKORP) deep seismic reflection studies in the western part of the Rhenish Massif
1991
Summary Within the DEKORP project (DEKORP: Deutsches Kontinentales Reflexionsseismisches Programm) a joint deep seismic reflection venture with the BELCORP (Belgian Continental Reflection Seismic Programme) group of the Belgian Geological Survey was carried out in 1987 across the Rhenish Massif, a part of the mid-European Variscides. This orogenic belt developed in the Upper Devonian/Carboniferous. Mostly Devonian rocks crop out at the surface. The Rhenish Massif is bordered by two sedimentary troughs: the sub-Variscan Foredeep in the north and the Permo-Carboniferous Saar-Nahe Basin in the south. In the east-west direction it is subdivided by the axial depression of the Eifel Nord-Sud Zone…
Middle to Late Ordovician arc system in the Kyrgyz Middle Tianshan: From arc-continent collision to subsequent evolution of a Palaeozoic continental …
2016
New geological, geochronological and isotopic data reveal a previously unknown arc system that evolved south of the Kyrgyz Middle Tianshan (MTS) microcontinent during the Middle and Late Ordovician, 467-444 Ma ago. The two fragments of this magmatic arc are located within the Bozbutau Mountains and the northern Atbashi Range, and a marginal part of the arc, with mixed volcanic and sedimentary rocks, extends north to the Semizsai metamorphic unit of the southern Chatkal Range. A continental basement of the arc, indicated by predominantly felsic volcanic rocks in Bozbutau and Atbashi, is supported by whole-rock Nd- and Hf-in-zircon isotopic data. epsilon(Nd(t)) of + 0.9 to -2.6 and epsilon(Hf…