Those studies showed that sulfate minerals
such as anhydrate, gypsum, and alunite are precipitated by reacting with S[O.sub.2] when Ca-rich minerals such as calcite and anorthite are present, which decreases the porosity of the rocks.
Stable isotope systematics of sulfate minerals
. Sulfate Minerals--Crystallography, Geochemistry and Environmental Significance, 40, 541-602.
In this modified ABA approach, a separate estimation of the acidity contained within poorly soluble Fe/Al hydroxy sulfate minerals
, termed retained acidity (RA), was introduced (Eqn 2) (Ahem et al.
As Curiosity climbs, it will also be traveling forward through Martian time, into sulfate minerals
. Thus the mission's scientists will be reading Mars's watery history in the order in which it happened.
3 Clay and sulfate minerals
precipitate from seawater as it is initially heated.
Water-soluble sulfate minerals
occur as coatings on the walls of the open pit sheltered underneath overhanging rocks.
(1997) Secondary Sulfate Minerals
from Alum Cave Bluff: Microscopy and Microanalysis.
Observations from orbit have identified exposures there of clay and sulfate minerals
that formed in wet environments.
Nearby, we discovered deposits of hydrated sulfate minerals
(containing [SO.sub.2] and [H.sub.2]O in their structure) and of nearly pure fine-grained hydrated silica (hydrated [SiO.sub.2]).
For example, bacteria that extract energy by metabolizing sulfate minerals
leave behind sulfides partially depleted of the heavier isotopes of sulfur, says Pascal Philippot, a geochemist at the Paris Geophysical Institute.
Hence the TPA measurement is not recovering acidity retained by these insoluble sulfate minerals
Scientists then announced that data gathered by Opportunity showed that rocks in Eagle had at one time been soaked by water, leaving behind a residue of sulfate minerals
and BB-size particles.