cyclothem

cyclothem

[′si·klə‚them]
(geology)
A rock stratigraphic unit associated with unstable shelf of interior basin conditions, in which the sea has repeatedly covered the land.
References in periodicals archive ?
As such, this sequence is part of a cyclothem (Gibling and Bird 1994) in a terrestrial environment of an extensive costal platform (Wightman et al.
Palynological and megafloral assemblages indicate that this formation is of Asturian-Cantabrian age, with the substage boundary occurring within Cyclothem 12, about 25 m above the Hub Coal Seam (Zodrow and Cleal 1985; Zodrow 1989a, b; Dolby 1988; Cleal et al.
Consequently, marine and nonmarine beds alternate and interfinger to form a pattern of transgressive and regressive rock deposition, which is commonly referred to as the classic Pennsylvanian cyclothem sequence.
Accurately calibrated radiocarbon dates are essential in correlating radiocarbon-dated phenomena with Milankovitch models, cyclothems, and with direct radiometric methods such as TL or U/ Th disequilibrium dating, which can be used to link culture to climate.
Late Carboniferous cyclothems and alluvial palaeovalleys in the Sydney Basin, Nova Scotia.
Trace element behavior and redox facies in core shales of Upper Pennsylvanian Kansas-type cyclothems.
Trace-element behavior and redox facies in core shales of Upper Pennsylvanian Kansas-type cyclothems.
Trace-element behaviour and redox facies in core shales of Upper Pennsylvanian Kansas-type cyclothems.
165), the Gore Lignite Measures were mainly deposited "in a range of fluvial channel, overbank splay, floodplain and swamp environments, as indicated by the presence of in situ terrestrial plant remains, lateral persistence of the multiple coal seams, common root-penetrated seat earths, large scale upward-fining clastic sequences typical of fluvial cyclothems, and the paucity of marine fauna.
The site is within a band of high chloride-sulfate groundwater along the Lower Meramec River Hills, which may be caused by groundwater flow through Pennsylvanian cyclothems containing pyrite and gypsum.
Cyclothems were globally widespread during the Pennsylvanian (Veevers and Powell 1987) and are evident in upper portions of the Pottsville Group (Algeo and Wilkinson 1988), but are rare in southeastern Ohio (Nadon 1998), and are entirely lacking in the Sharon Formation.