Geologic Map of the Niobe Planitia Region (I-2467), Venus.
Abstract
We present a 1:10M scale map of the Niobe Map Area (NMA) of Venus
(0N-57N/60E-80E). Geologic mapping employed NASA Magellan synthetic
aperture radar and altimetry data. The NMA geologic map, and its
companion Aphrodite Map Area (AMA), cover ~25% of
Venus’ surface, providing with an important and unique perspective to
study global and regional geologic processes. Both areas display a
regional coherence of preserved geologic patterns that record three
sequential geologic eras: the ancient era, the Artemis superstructure
era, and the youngest fracture zone era. The NMA preserves a limited
record of the fracture zone era, contrary to the AMA. However, the NMA
host a diverse and rich assemblage of material and structures of the
ancient era, and structures that define the Artemis superstructure era,
with a footprint covering more than 25 percent of the surface of Venus.
These two eras likely overlap in time and account for the formation of
basement materials and lower plain units. Impact craters formed
throughout the NMA recorded history. Approximately 40% of the impact
craters show interior flood deposits, indicating that a significant
number of NMA impact craters experienced notable geological events after
impact crater formation. This and other geologic relations record a
geohistory inconsistent with postulated global catastrophic resurfacing.
Together, the NMA and the AMA record a rich geologic history of the
surface of Venus that provide a framework to formulate new working
hypotheses of Venus evolution, an to plan future studies of the planet.