Fluid flow in the core is assumed to consist of a slowly varying (on time scales > magnetic diffusion time) part and a smaller, rapidly varying part as in the theory of the hydromagnetic dynamo put forward by Braginsky (1965). On the basis of this theory, geomagnetic secular variation models for the last 150 years are used to determine a rapidly varying, axisymmetric, poloidal motion of the flu...

The preliminary results of a geochemical survey of fumaroles and hot springs in the Torfajökull geothermal area, South Iceland, are presented. The total gas content in fumarole steam ranges from about 20 to roughly 25,000 mmole/kg, with carbon dioxide as the main component. Gas geothermometers indicate subsurface temperatures of about 300°C in the northern, western, and central parts of the are...

Fifteen fish species, totalling 149 specimens, were cytochrome c oxidase I sequenced— barcoded—from Northern (Atlantic and Mediterranean) and Southern (Australasian) Hemisphere waters. Thirteen species showed no significant evidence of spatial genetic differentiation for this gene, although small sample sizes reduced statistical power. For marine fish, barcodes collected in one part of a specie...

Consistent evidence for a poorly ventilated deep Pacific Ocean that could have released its radiocarbon-depleted carbon stock to the atmosphere during the last deglaciation has long been sought. Such evidence remains lacking, in part due to a paucity of surface reservoir age reconstructions required for accurate deep-ocean ventilation age estimates. Here we combine new radiocarbon data from the...

changes in abundance and biomass of cyanobacteria have been studied in the southern part of the caspian sea (the stretch between tonekabon and amirabad) in four seasons (spring, summer, autumn, winter) in which samples were taken from five depths of 5, 10, 20, 50 and 100 meters in the stations of tonekabon, noushahr, babolsar and amirabad. samples were fixed in formalin (2-2.5%) before transfer...

Quantitative subsidence analysis of 26 wells in the Lusitanian basin provides new constraints on the western Iberian Mesozoic passive margin development. Backstripped tectonic subsidence curves show a three-fold subdivision of vertical motions from Late Triassic onward. Continental rifting was initiated during the Late Triassic and Early Jurassic. From Middle Jurassic onward a distinct differen...

in current paper, geometrical relationship between the longitudinal faults of a zone of the folded zagros, surrounding asef mountains (north of shiraz) that follow the northwest-southeast structural trend (eg. zarghan, katah and sadra faults) has been studied. a western and southern zone of zagros mountain chain called folded zagros has a length of about 1375 km and a width between 120 and 250 ...