Findings and Recommendations - New Research Opportunities in the Earth Sciences - page 87

build on the foundations of sustained core subdisciplinary research to make major
advances in the Earth sciences in the next decade.
THE EARLY EARTH
A large number of critical processes and events formed Earth and guided its
evolution to the present state. Unique to the Hadean Eon (the first 500 million years
of Earth history) were the formation of planetesimals, planetary embryos, and the
moon; the mineralogy, petrology, and dynamics of magma oceans; the dynamics and
chemistry of core formation and initiation of the geodynamo; formation of the earliest
crust, atmosphere, and ocean; acquisition of surface volatiles; transition from an
impact-dominated surface to one shaped by plate tectonics; and the terrestrial
consequences of the young sun. The 2008 NRC report Origin and Evolution of Earth
identified the question “What happened during Earth's dark age?” as a research grand
challenge in the Earth sciences.
There are multiple avenues for new insights into the early Earth. A primary
objective is to increase the inventory of early Earth samples by expanding the search
for yet older rocks and minerals. Still another is to quantify early Earth history using
novel combinations of isotope systems and new micro and nanotechnologies.
Sustained progress will require synthesizing geochronology and geochemical data
with dynamical models that bridge the gap between planet formation and plate
tectonics by incorporating the highly energetic conditions of the early Earth.
Advances in high-performance computing hardware and parallel advances in software
will make it possible to model processes such as giant impacts, magma oceans, crust,
and core formation using realistic Earth parameters. The challenges of early Earth
history argue for strengthening links with astronomy and astrophysics, planetary
science, molecular biology, and biochemistry.
Finding 1: Organizing the diverse expertise within EAR and beyond would address
major questions about the early Earth. Advances can come from collaborations with
astronomy, astrophysics, planetary science, exoplanet detection and characterization,
and astrobiology. EAR coordination with the research efforts of the National
Aeronautics and Space Administration (NASA) is particularly relevant, as NASA
supports research on detection and comparison with exoplanetary systems; origins of
life and biological materials in our solar system; meteorite, asteroid, and solar system
dust sampling; and large-scale modeling of planetary system formation.
Finding 2: Expanding searches for and characterization of the oldest rocks and
minerals can provide new constraints on the earliest surface environments and Earth
differentiation processes.
Finding 3: Refinements in early Earth chronology and rates of early Earth processes
can be enabled through novel applications of short- and long-lived isotope systems.