Journal ArticleDOI
Diagenesis of Basalts from the Pasco Basin, Washington--I. Distribution and Composition of Secondary Mineral Phases
L. V. Benson,L. S. Teague +1 more
TLDR
The principal components of secondary mineral assemblages found in Pasco Basin basalts are iron-rich smectite (nontronite), clinoptilolite, and silica as mentioned in this paper.Abstract:
The principal components of secondary mineral assemblages found in Pasco Basin basalts are iron-rich smectite (nontronite), clinoptilolite, and silica. Silica occurs as quartz, cristobalite, tridymite, and opal-CT. Extractable iron within the nontronite suggests the presence of an iron-bearing oxyhydroxide phase intercalated with the nontronite. Other components present in minor or trace amounts are mordenite, celadonite, apatite, pyrite, phillipsite, gypsum, erionite, and chabazite. The generalized precipitation sequence with time and/or depth was found to be clay (usually nontronite) clinoptilolite silica and/ or clay. Nontronite, the first phase to form, is present at nearly al sampled depths. Clinoptilolite is apparently restricted to depths below about 350 m. Quartz is ubiquitous whereas opal and cristobalite appear to be abundant only below 600 m. Mordenite occurs only at depths below about 900 m, which correlates roughly with the first occurrence of dissolution-etched clinoptilolite. These observations as well as comparisons with data on secondary mineral assemblages from other basaltic and felsic systems suggest that the geochemical evolution of Pasco Basin basalts probably occurred under conditions similar to those existing today.read more
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Journal ArticleDOI
Surface clay formation during short-term warmer and wetter conditions on a largely cold ancient Mars
Janice L. Bishop,Janice L. Bishop,Alberto G. Fairén,Alberto G. Fairén,Joseph R. Michalski,L. Gago-Duport,Leslie L. Baker,Michael A. Velbel,Michael A. Velbel,Christoph Gross,Elizabeth B. Rampe +10 more
TL;DR: A geochemical model for the state of early Mars suggests that short-term warm events grafted onto a generally cold climate could form Al-rich phyllosilicates in short-lived surface water bodies and Mg-rich ones in hydrothermal subsurface environments.
Journal ArticleDOI
The genesis of zeolites
TL;DR: In this article, the equilibrium diagrams of zeolites and the different possibilities of synthesizing zeolite starting from chemicals, minerals, and natural glasses are reviewed so to have a general picture of the conditions of crystallization of these minerals.
Journal ArticleDOI
The role of basalt weathering in the Sr isotope budget of the oceans
A.S Taylor,Antonio C. Lasaga +1 more
TL;DR: Using a coupled fluid flow-mass transfer model to calculate the Sr flux resulting from the weathering of the young Columbia River basalts, it can be shown that the dissolution of the reactive phases in the extensive continental flood basalt could have caused the significant inflection in the marine Sr isotope record that occurred approximately 15 million years ago as mentioned in this paper.
Journal ArticleDOI
Microfossils and Paleoenvironments in Deep Subsurface Basalt Samples
TL;DR: Secondary minerals near and within fractures in Columbia River basalts contain objects the size and shape of bacteria, commonly rods or ellipses but also include cocci and diplococci forms, vibrioids and club-shaped rods, and associated pairs of objects that suggest cellular division by binary fission as discussed by the authors.
Journal ArticleDOI
The Nature, Origin and Distribution of Authigenic Clay Minerals from Middle Jurassic Ravenscar and Brent Group Sandstones
TL;DR: Pore-lining illite, porelining chlorite and pore-filling vermiform kaolinite in the Ravenscar Group mutually exclude each other because of depositional porewater chemistry; seawater in the case of the illite and anoxic freshwater in case of chlorite, and oxygenated freshwater in the example of the kaoline.