Search results for "Devonian"
showing 10 items of 77 documents
The unique fossil assemblage from the Lode Quarry (Upper Devonian, Latvia)
2001
The unique fossil fauna from the Lode clay quarry, lower Frasnian, Latvia, includes a diverse ichthyofauna of at least 15 taxa of agnathans and gnathostomes, representing most of the major taxa of Devonian vertebrates. Six new fish taxa (five species and one genus) were discovered during the last ten years. Exceptionally well-preserved juvenile fishes (<i>Asterolepis ornata, Lodeacanthus gaujicus</i>) provide unique data on ontogenetic change. Diverse arthropods are recorded. Parasitic platyhelminth remains in juvenile fish bodies is their first discovery in the fossil record, and represents the oldest parasitic association ever found. A complete faunal and floral list for the L…
Controls of mud mound formation: The Early Devonian Kess-Kess carbonates of the Hamar Laghdad, Antiatlas, Morocco
1992
The origin and development of Early Devonian (late Pragian to late Zlichovian; predominantly uppermost Zlichovian as indicated by conodont faunas) mud mounds of the Hamar Laghdad area in the eastern Antiatlas, Morocco, are controlled by extrinsic and intrinsic factors. Extrinsic factors include the existence of a paleohigh (Lochkovian volcaniclastics), unidirectional currents and repeated storm events as well as sea level fluctuations. Intrinsic, biologically induced factors are the preferred growth of organisms on the top and the flanks of the mounds because of more favourable ecological conditions, and a rapid synsedimentary lithification of the steep mound flanks by interskeletal cementa…
Working to the conservation and good use of the Devonian palaeontological heritage in Floresta, Boyacá (Colombia): a review of teaching case studies …
2019
The Floresta Massif, located in the Eastern Cordillera of Colombia, has a diverse and precious natural heritage. It is one of the areas that contains an exceptional palaeontological heritage of the Middle Devonian not only of Colombia, but also of South America. This heritage is represented by fossil specimens of marine fauna and terrestrial flora (correlated with North America and Europe) of the Floresta and Cuche Formations, respectively. Since 2004, actions made by several academic and research institutions, community and local government have introduced schoolchildren, teenagers and University students to art and science, and have promoted the conservation of palaeontological heritage a…
Palaeomagnetic investigations in the Hercynian mountain belt of central Europe
1983
Abstract The palaeomagnetism of sediments and volcanics of Middle Devonian to Early Carboniferous age has been studied in the Hercynian realm of the Vosges, Harz and Franconian Forest (France and Germany). After appropriate cleaning, characteristic directions of natural remanent magnetization (NRM) have been determined, which are considered to be of pretectonic origin according to rock magnetic and structural geological evidence. A mean palaeopole for the Devonian rocks in the areas investigated was determined at — 29.7°N and 9.0°E. The site latitude derived from the Devonian rocks agrees very well with that observed in Great Britain and Britanny. The significant difference in longitude bet…
New data on the Lower Devonian chondrichthyan fauna from Celtiberia (Spain)
2010
Lower Devonian microvertebrate remains from Spain, including localities in Celtiberia and Cantabrian Mountains, have been extensively studied during recent decades (e.g., Mader, 1986; Wang, 1993; ...
The middle and upper Lochkovian (Lower Devonian) conodont successions in key peri-Gondwana localities (Spanish Central Pyrenees and Prague Synform) a…
2015
Detailed correlation, based on conodont sequences, between middle and upper Lochkovian carbonate successions from two key peri-Gondwanan regions, the Spanish Central Pyrenees and the Prague Synform, is attained for the first time. This correlation facilitates the definition of tie points for further multidisciplinary studies that seek to establish high-resolution temporal subdivision and global correlation. Some intervals have a precision of less than 0.5 Ma, which is significantly greater than in previous studies. The estimated elapsed time considered herein is about 3.2 Ma and is subdivided into five major zones of global scope: transitanstrigonicus, trigonicus-kutscheri, kutscheri-pandor…
Annotations to the Devonian Correlation Table, R 350–356 di-ds 06: Spain
2006
Annotations to Devonian Correlation Table, R 357–360 di-ds 06: Spanish Central Pyrenees, southern part
2006
Devonian arc-related magmatism in the Tseel terrane of SW Mongolia: chronological and geochemical evidence
2009
Abstract: The Tseel terrane in the Gobi Desert of SW Mongolia consists of a composite crustal segment of imbricated sheets of high- and low-grade metamorphic rocks of predominantly middle Palaeozoic age. New sensitive high-resolution ion microprobe (SHRIMP) zircon ages of 396 ± 3 Ma (2σ) and 397 ± 3 Ma (2σ) for two calc-alkaline metarhyolite samples indicate arc volcanism during the early Devonian. An undeformed feldspar porphyry cross-cutting the early Devonian low-grade sequence yielded an emplacement age of 279 ± 2 Ma (2σ). Geochemical and Nd isotopic data for low-grade mafic metavolcanic rocks are consistent with melting of moderately depleted upper mantle sources in a transitional arc–…