『Abstract
The mineralogy of terrestrial planets evolves as a consequence
of a range of physical, chemical, and biological processes. In
pre-stellar molecular clouds, widely dispersed microscopic dust
particles contain approximately a dozen refractory minerals that
represent the starting point of planetary mineral evolution. Gravitational
clumping into a protoplanetary disk, star formation, and the resultant
heating in the stellar nebula produce primary refractory constituents
of chondritic meteorites, including chondrules and calcium-aluminum
inclusions, with 〜60 different mineral phases. Subsequent aqueous
and thermal alteration of chondrites, asteroidal accretion and
differentiation, and the consequent formation of achondrites results
in a mineralogical repertoire limited to 〜250 different minerals
found in unweathered meteorite samples.
Following planetary accretion and differentiation, the initial
mineral evolution of Earth's crust depended on a sequence of geochemical
and petrological processes, including volcanism and degassing,
fractional crystallization, crystal setting, assimilation reactions,
regional and contact metamorphism, plate tectonics, and associated
large-scale fluid-rock interactions. These processes producted
the first continents with their associated granitoids and pegmatites,
hydrothermal ore deposits, metamorphic terrains, evaporites, and
zones of surface weathering, and resulted in an estimated 1500
different mineral species. According to some origin-of-life scenarios,
a planet must progress through at least some of these stages of
chemical processing as a prerequisite for life.
Biological processes began to affect Earth's surface mineralogy
by the Eoarchean Era (〜3.85-3.6 Ga), when large-scale surface
mineral deposits, including banded iron formations, were precipitated
under the influences of changing atmospheric and ocean chemistry.
The Paleoproterozoic “Great Oxidation event” (〜2.2 to 2.0 Ga),
when atmospheric oxygen may have risen to ＞1％ of modern levels,
and the Neoproterozoic increase in atmospheric oxygen, which followed
several major glaciation events, ultimately gave rise to multicellular
life and skeletal biomineralization and irreversibly transformed
Earth's surface mineralogy. Biochemical processes may thus be
responsible, directly or indirectly, for most of earth's 4300
known mineral species.
The stages of mineral evolution arise from three primary mechanisms:
(1) the progressive separation and concentration of the elements
from their original relatively uniform distribution in the pre-solar
nebula; (2) an increase in range of intensive variables such as
pressure, temperature, and the activities of H2O,
CO2, and O2; and (3)
the generation of far-from-equilibrium conditions by living systems.
The sequential evolution of Earth's mineralogy from chondritic
simplicity to Phanerozoic complexity introduces the dimension
of geologic time to mineralogy and thus provides a dynamic alternate
approach to framing, and to teaching, the mineral sciences.
Keywords: Pre-solar minerals; meteorite minerals; biominerals;
organominerals; teaching mineralogy』
Introduction
The era of planetary accretion (＞4.55 Ga)
Stage 1. Formation of primary chondritic minerals (＞4.56
Ga)
Stage 2. Aqueous alteration, metamorphism, and differentiation
of planetesimals (4.56 to 4.55 Ga)
The era of crust and mantle reworking (4.55 to 2.5 Ga)
Stage 3. Initiation of igneous rock evolution (4.55 to 4.0
Ga)
Stage 4. Granitoid production and the initiation of craton formation
(〜4.0 to 3.5 Ga)
Stage 5. Plate tectonics and large-scale hydrothermal reworking
of the crust (＞＞3.0 Ga)
Stage 6. The anoxic biosphere of the Archean Eon (3.9 to 2.5
Ga)
Minerals and the origin of life
The era of biologically mediated mineralogy (2.5 Ga to present)
Stage 7. The Paleoproterozoic “Great Oxidation Event” (2.5
to 1.9 Ga)
Stage 8. The “intermediate ocean” (1.9 to 1.0 Ga)
Stage 9. The Neoproterozoic snowball Earth and oxygenation events
(1.0 to 0.542 Ga)
Stage 10. Phanerozoic biomineralization (＜0.542 Ga)
Discussion
Three processes that drive mineral evolution
Comparative planetology
A comment on the term “evolution”
Complex evolving systems
Concluding remarks: Framing mineral sciences
Acknowledgments
References cited