Annual Planetary Geologic Mappers Meeting (2016)
7026.pdf
GEOLOGIC MAP OF NEW HORIZONS' ENCOUNTER HEMISPHERE OF CHARON. S.J. Robbins0,1, J.R.
Spencer1, R.A. Beyer2,3, P. Schenk4, J.M. Moore3, W.B. McKinnon5, R.P. Binzel6, M.W. Buie1, B.J. Buratti7, A.F.
Cheng8, W.M. Grundy9, I.R. Linscott10, H.J. Reitsema11, D.C. Reuter12, M.R. Showalter2, G.L. Tylerl, L.A. Young1,
C.B. Olkin1, K. Ennico3, H.A. Weaver8, S.A. Stern1, the New Horizons GGI Theme Team, New Horizons Pluto Encounter Team, New Horizons LORRI Instrument Team, and New Horizons MVIC Instrument Team.
0
[email protected], 1Southwest Research Institute, 1050 Walnut Street, Suite 300, Boulder, CO 80302. 2Sagan Center
at the SETI Institute. 3NASA Ames Research Center, Moffett Field, CA 84043. 4Lunar and Planetary Institute, Houston, TX.
5
Washington University in St. Louis, St. Louis, MO. 6Massachussetts Institute of Technology, Cambridge, MA. 7NASA Jet
Propulsion Laboratory, California Institute of Technology, Pasadena, CA. 8The Johns Hopkins University, Baltimore, MD.
9
Lowell Observatory, Flagstaff, AZ. 10Stanford University, Stanford, CA. 11Ball Aerospace (retired), Boulder, CO. 12NASA
Goddard Space Flight Center, Greenbelt, MD.
estimate the majority of the larger tectonic features
formed ~4 Ga. However, crater density maps [9] show
a deficit of craters in some areas that are possibly due
to disruption by tectonic features, indicating that some
tectonic activity may be significantly younger.
Vulcan Planum Mapping: Vulcan Planum is a
younger region than Oz Terra [2,4,6,9], indicated by
the spatial density of large craters. In topography, it
shows a "moat" at its margins, possibly indicating a
frozen viscous fluid flow [4,6]. We are in the process
of studying this region [6] and the geomorphologic
map has revealed only two primary types of landscape:
smooth plains (Sm), and patterned ground (Pg1 and
Pg2) which resembles an elephant skin-like texture.
Near its southern margin, it also shows numerous
broad warps that may represent upwelling.
Open Questions and Issues: Two primary issues
have arisen which we are working to solve to achieve
our goal of an encounter hemisphere map: (1) What is
the best way to integrate a >30× difference in resolution of our datasets over the map region? (2) How do
we deal with a significant difference in sun angle
across the encounter hemisphere? We hope to receive
input at the June meeting on these questions.
References: [1] White, O.L. et al. (this volume). [2] Singer,
K.N. et al. (this volume). [3] Stern, S.A. et al. (2015). [4]
Moore, J.M. et al. (2016). [5] Beyer R.A. et al. (in rev). [6]
Spencer, J. et al. (in prep). [7] Cheng, A.F. et al. (2008). [8]
Reuter, D.C. et al. (2008). [9] Robbins, S.J. et al. (in rev).
[10] Schenk, P. et al. (2016).
Funding: This work was funded by the New Horizons mission within NASA's New Frontiers program.
Percent of Surface per Pixel Scale
12
100
Histogram
Cumulative
10 19.6% of surface not observed
80
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Pixel Scale (km/px)
6
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Cumulative Percent of Surface per Pixel Scale
Introduction: NASA's New Horizons spacecraft
revealed diverse landscapes on both Pluto and Charon
during its July 2015 flyby, and we have begun geomorphologic mapping efforts [1,2] to better understand
the different landforms, sequence and timing, and how
they may have formed. The work herein focuses on
Charon, and images from the spacecraft have revealed
a variety of features [3,4] that include hundreds of tectonic manifestations [5], and vast but diverse plains [6].
Here, we present progress in mapping the hemisphere
that New Horizons best imaged during its flyby.
Available Data: Data taken directly by New Horizons relevant for geomorphologic mapping come from
the LORRI (LOng-Range Reconnaissance Imager) [7]
camera, MVIC (Multi-spectral Visible Imaging Camera) [8] camera, and LEISA (Linear Etalon Imaging
Spectral Array) [8] imaging spectrometer. LORRI is
panchromatic and provided images of Charon at up to
160 m/px, MVIC 4-color images are up to 620 m/px,
and LEISA spectral cubes are up to 5 km/px. Figure 1
shows the fractional coverage of Charon at panchromatic wavelengths. Additional, derived data useful for
mapping includes craters (useful for ages and as units
if large enough) [9], reconstructed topography from
stereo [10] and photoclinometry, and mineralogy maps
(in progress by the team). Our primary dataset for
geomorphologic mapping of Charon is the panchromatic map reconstructed from LORRI and MVIC data.
Areas Identified for Nomenclature: For ease of
communication, the New Horizons team developed
informal names used herein. On Charon, these include
two dark macula, 14 impact craters, six chasmata, and
three large montes. In addition, the very broad area
north of a large tectonic belt has been termed "Oz Terra" and the smoother plains generally south of the belt
are "Vulcan Planum."
Tectonic Features Mapping: Initial geomorphologic mapping focused on tectonic features in support
of Beyer et al. [5]. This map was made without the
assistance of topography and will see significant revision once topography solutions are finalized, especially
in Oz Terra where we are limited to near-noon sun.
Beyer et al. [5] found the majority of tectonic features
are aligned northeast-southwest; this parallels the massive tectonic belt implying these features are likely
related. Based on superposed, large impact craters, we
Figure 1: Pixel scale and fractional global coverage of
New Horizons panchromatic imaging of Charon.
Annual Planetary Geologic Mappers Meeting (2016)
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Figure 2: Map of the main tectonic features on the encounter hemisphere of Charon [5], color-coded by type.
Figure 3: Preliminary map of Vulcan Planum area / material used in Spencer et al. [6].
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