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Silurian and Lower Devonian plant assemblages from the Anglo-Welsh Basin; a palaeobotanical and palynological synthesis


, : Silurian and Lower Devonian plant assemblages from the Anglo-Welsh Basin; a palaeobotanical and palynological synthesis. Geological Journal 39(3-4): 375-402

A comprehensive survey of plant assemblages from Upper Silurian (Gorstian-Pridoli) and Lower Devonian (Lochkovian-Pragian) localities in South Wales and the Welsh Borderland is presented, together with some comments on recent improvements in dating and correlation. Spore assemblages provide a stratigraphic framework for plant evolutionary studies and, along with microvertebrates, enable correlation from continental to marine rocks, i.e. near-shore to shelf deposits. While it is recognized that the assemblages provide the most complete and extensive record of the history of vascular plants in a restricted geographical area during the time interval, it seems likely that major evolutionary innovation occurred elsewhere. The plants themselves display a number of types of fossilization. Particularly important are the pyrite permineralizations which have helped in the elucidation of the ultrastructure of tracheids in early vascular plants. Minute, coalified, relatively uncompressed fossils (mesofossils) from the Pridoli Lochkovian of the Welsh Borderland are hypothesized to be the products of wildfire, the earliest records to date. In addition to displaying often exquisite anatomical detail, the sporangia contain spores which have been linked to those in dispersed assemblages. Such relationships are helpful in the reconstruction of local and regional vegetation, even in the absence of meso- and megafossils. However, because these fossils are allochthonous and preserved in fluvial sediments, the habitats of the plants remain uncertain. A new hypothesis suggests that interfluvial areas, where calcretes are interpreted as relicts of vertisols and a seasonally dry climate, provided refugia in the Lower Devonian for the cryptospore-producing plants which dominated Ordovician and Lower Silurian land vegetation, while vascular plants colonized areas in the immediate vicinity of rivers. Variation in regional vegetation is explored via comparisons of composition of spore assemblages in southern Britain and Scotland and timing of appearances of derived taxa, integrated with limited information on the spore producers. Abstract Copyright (2004), Wiley Periodicals, Inc.

US$19.90

DOI: 10.1002/gj.997


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Ingason, Aés.; Søeby, K.; Timm, S.; Wang, A.G.; Jakobsen, K.D.; Fink-Jensen, A.; Hemmingsen, R.; Berg Rasmussen, H.; Werge, T., 2006: No significant association of the 5' end of neuregulin 1 and schizophrenia in a large Danish sample. Neuregulin 1 has been implicated as a susceptibility gene in schizophrenia. Several research groups have reported association with the 5' end of the gene although no causative variant has been reported. We have investigated whether there is a...

Ha, Y.Wan.; Na, Y-Cheol.; Seo, J-Ju.; Kim, S-Na.; Linhardt, R.J.; Kim, Y.Shik., 2006: Qualitative and quantitative determination of ten major saponins in Platycodi Radix by high performance liquid chromatography with evaporative light scattering detection and mass spectrometry. Saponins in Platycodi Radix (platycosides) exhibit potent biological activities in mammalian systems, including several beneficial effects such as anti-inflammatory, immunomodulatory and anti-obesity activities. In this study, we developed a new...

Diez J.; Simon M.A.; Anton F.; Indart F.J.; Prieto J., 1990: Tubular sodium handling in cirrhotic patients with ascites as analyzed by the renal lithium clearance method. The proximal and distal sodium reabsorption were calculated from lithium clearance in 21 healthy controls and 24 cirrhotic patients with ascites after 4 days under a sodium-restricted diet. The values of fractional lithium clearance were lower in...

Hasenhuettl C.H.; Rantitsch G.; Russegger B., 1992: Thermal history of two Paleozoic areas of Austria (Graz Paleozoic; Carnic Alps). Terra Abstracts: Pages 29. 1992.

Normann E.; Normann T., 1972: Uptake of tritiated labeled commercial toluidine blue and subfractions thionine toluidine blue and azur a in the parathyroids of rabbits. Scandinavian Journal of Clinical & Laboratory Investigation 29(4): 403-406

Carson, D.D.; Julian, J.; Jacobs, A.L., 1992: Uterine stromal cell chondroitin sulfate proteoglycans bind to collagen type I and inhibit embryo outgrowth in vitro. Chondroitin sulfate proteoglycans (CSPGs) are the major class of proteoglycans synthesized by mouse uterine stroma in vitro (Jacobs, A. L., and Carson, D. D. (1991). J. Biol. Chem. 266, 15,464–15,473). In the present study, stromal CSPGs were is...

Lin, R.M.; Takahashi, P.H.; Sial, S.; Lee, T.; Osato, M.; Feng, J.; Sze, G.; Arnell, T.; Stamos, M.; Eysselein, V., 2001: Palliative stenting for gastroduodenal and colorectal obstruction. Journal of Investigative Medicine 49(1): 43A, January

Gerasimenko, P.P.; Kazeev, K.N.; Tslaf, Z.Z.; Kertsman, V.I.; Effemov, A.V., 1974: Rare localization of pheochromocytoma. Klinicheskaia Meditsina 52(7): 98-103

Asbury A.K.; Martin D.B., 1969: Ischemic neuropathies associated with diabetes mellitus. Diabetes 18(SUPPL): 344

Allen John Eliot, 1946: Geology of the San Juan Bautista Quadrangle, California. 56(12, Part 2): 9-75 1946