Now showing items 21-30 of 273
The Neoproterozoic (1000-540 Ma) glacial intervals: No more snowball earth?
(Elsevier, 1994-05)
The Neoproterozoic interval (1000-540 Ma) contains ample evidence for a series of glacial intervals. These include the 750-700 Ma Sturtian glaciation, the 625-580 Ma Marinoan-Vendian glaciation and the 600-550 Ma Sinian ...
Genesis and solvus relations of submicroscopically intergrown paragonite and phengite in a blueschist from northern California
(Springer-Verlag, 1991-01)
Electron microbeam techniques have been used to examine submicroscopically intergrown paragonite, phengite and chlorite from the South Fork Mountain Schist of the Franciscan Terrane of northern California, which was subjected ...
Origin and chemical evolution of formation waters from Silurian-Devonian strata in the Illinois basin, USA
(Elsevier, 1991-01)
A suite of formation-water samples from Silurian-Devonian reservoirs in the Illinois basin has been analyzed for major, minor and trace element concentrations and for H, O and Sr isotopic compositions in order to interpret ...
Gold deposition by sulfidation of ferrous Fe in the lacustrine sediments of the Pueblo Viejo district (Dominican Republic): The effect of Fe-C-S diagenesis on later hydrothermal mineralization in a Maar-Diatreme complex
(Elsevier, 1992-09-10)
The Pueblo Viejo district, located in the Cordillera Central of the Dominican Republic, contains large Au-Ag deposits associated with acid-sulfate alteration within spilites, conglomerates and carbonaceous sedimentary rocks ...
Lakes of the Huron basin: their record of runoff from the laurentide ice sheet
(Elsevier, 1994)
The 189,000 km2 Huron basin is central in the catchment area of the present Laurentian Great Lakes that now drain via the St. Lawrence River to the North Atlantic Ocean. During deglaciation from 21-7.5 ka BP, and owing to ...
Stand Characteristics and Leaf Litter Composition of a Dry Forest Hectare in Santa Rosa National Park, Costa Rica
(Blackwell Publishing Ltd, 1997-12)
One hectare of tropical dry forest in Guanacaste Conservation Area, Costa Rica was mapped and all trees larger than 10 cm diameter at breast height (DBH) identified. The same hectare was sampled for leaf litter and the two ...
Effects of fuel and forest conservation on future levels of atmospheric carbon dioxide
(Elsevier, 1992-03)
We develop a numerical simulation of the global biogeochemical cycles of carbon that works over time scales extending from years to millions of years. The ocean is represented by warm and cold shallow water reservoirs, a ...
Paleomagnetism of the Late Archean Nyanzian System, western Kenya
(Elsevier, 1994-10)
The Nyanzian System lavas of western Kenya are believed to be the oldest rocks of the Tanzanian Craton. Intrusive age relationships suggest an age [ges]2850 Ma although direct attempts at dating the Nyanzian have produced ...
Mineral inclusions in pyrope crystals from Garnet Ridge, Arizona, USA: implications for processes in the upper mantle
(Springer-Verlag; Springer-Verlag Berlin Heidelberg, 1999-05)
Mineral inclusions in pyrope crystals from Garnet Ridge in the Navajo Volcanic Field on the Colorado Plateau are investigated in this study with emphasis on the oxide minerals. Each pyrope crystal is roughly uniform in ...