We are funded by the NASA Mars Data Analysis Program (MDAP) to produce 1:1,000,000 scale geologic maps of Arsia Mons and Pavonis Mons, as well as conduct mapping of surrounding regions. In this abstract we discuss progress made during years 1 and 2 of the 4-year project

Bleacher, J. E.

Garry, W. B.

Greeley, R.

Shean, D.

Williams, D. A.

NASA Technical Reports Server

GEOLOGIC MAPPING OF ARSIA AND PAVONIS MONTES.  D.A. Williams1, W.B. Garry2, J.E. Bleacher3, 
D. Shean4, R. Greeley1*. 1School of Earth & Space Exploration, Arizona State University, Tempe, AZ 85287 
(David.Williams@asu.edu); 2Planetary Science Institute, Tucson, AZ; 3Planetary Geodynamics Division, NASA 
Goddard Spaceflight Center, Laurel, MD; 3University of Washington, Seattle, WA. *Deceased. 
 
Introduction: We are funded by the NASA Mars 
Data Analysis Program (MDAP) to produce 
1:1,000,000 scale geologic maps of Arsia Mons and 
Pavonis Mons, as well as conduct mapping of sur-
rounding regions. In this abstract we discuss progress 
made during years 1 and 2 of the 4-year project. 
Objectives: The scientific objectives of this map-
ping project include: 1) Determining the areal extent, 
distribution, and age relationships of different lava 
flow morphologies (Fig. 1, next page) on the main 
flanks, rift aprons, and associated small-vent fields of 
Arsia and Pavonis Montes to identify and understand 
changes in effusive style across each volcano, and to 
provide insight into Martian magma production rates. 
This work builds on a preliminary study performed by 
Co-I Bleacher as part of his Ph.D. dissertation [1]. Re-
sults will provide insight into the overall volcanic evo-
lution of each structure, enable comparisons between 
volcanoes, and determine the extent of each shield’s 
contribution to the Tharsis plains; 2) Determining the 
areal extent and distribution of purported glacial and 
aeolian deposits on the flanks of each shield and their 
relationship to the lava flows. Results will establish a 
volcano-wide understanding of the nature of potential 
lava-ice interactions and the contribution of aeolian 
cover to the current form of the shields, enabling com-
parison among the shields potentially in different stag-
es of development; and 3) Characterizing erosional and 
tectonic features, such as rift zone graben, flank terrac-
es, and channel networks present on the flanks, rift 
aprons, and small-vent fields (Fig. 2, next page), to 
determine their relationships to volcanic materials and 
processes. 
Results: We are completing our year 2 objectives 
on schedule. Our objectives for year 2 include: 1) Re-
view and refine the mapping of structural features over 
both Arsia and Pavonis Montes volcanoes (Fig. 3a,b, 
next page); 2) Determine the material units to be 
mapped on Arsia and Pavonis Montes, using the map-
ping of Olympus Mons as a template [2]; and 3) Begin 
mapping long lava flows throughout the map area and 
develop criteria to determine the stratigraphy of over-
lapping lava flows. In Fall 2012 we will apply the ma-
terial unit definition and characterization methodology 
for the Olympus Mons to the Tharsis Montes, and be-
gin unit mapping. Material unit mapping will be the 
primary tasks of years 3 and 4. 
Long Lava Flow Mapping on Arsia Mons:  The 
southwest rift apron on Arsia Mons is comprised of 
several lava flows tens to hundreds of kilometers long.  
One aspect of this project is to map the lengths and 
area of these lava flows (Fig. 4).  Thirty-five lava 
flows have been mapped to date. They range in length 
from 21 to 228 km and area from 65 to 2685 km2.  
These values represent a minimum because the flows 
are partially buried by other flows, concealing their 
true dimensions and source areas.  From our prelimi-
nary mapping, these flows are typically leveed flows, 
and the flows with shorter length and lower area are 
observed closer to the chasmata on the flank of Arsia 
Mons, a potential source area for lava flows on the 
apron. 
 
 
 
Figure 4. Lava flows mapped on the southwest rift 
apron of Arsia Mons, color coded by polygon area on 
the THEMIS daytime basemap. Light Yellow: 65-271 
km2, Dark Yellow: 272-491 km2, Red: 492-968 km2, 
Purple: 969-1596 km2, Blue: 1597-2685 km2. Part of 
Arsia Mons caldera is visible at the top of the image. 
References: [1] Bleacher, J.E., R. Greeley, D.A. 
Williams, S.R. Cave, and G. Neukum (2007), Trends 
in effusive style at the Tharsis Montes, Mars, and im-
plications for the development of the Tharsis province, 
J. Geophys. Res., 112, E09005, doi:10.1029/2006JE 
002873. [2] Bleacher et al. (2012), this meeting 1805. 
 
Figure 1 (next page). Type examples of volcanic units mapped in the Tharsis Montes, using HRSC and THEMIS data. From left 
to right, top to bottom: A) channel-fed flows (CFF), B) tube-fed flows (TFF), C) raised ridges, D) tabular flows, E) fissure-fed 
flow fields, F) low shields, G) cones, H) a mottled unit, I) a hummocky unit, J) a smooth unit, K) collapse of non-impact origin, 
and L) channel network terrain. Modified from [1].  
1528.pdf43rd Lunar and Planetary Science Conference (2012)
https://ntrs.nasa.gov/search.jsp?R=20120009831 2019-08-30T20:31:57+00:00Z
GEOLOGIC MAPPING OF THARSIS MONTES: D.A. Williams et al. 
 
 
Figure 2 (below). Color-coded altimetry map of the central Tharsis region of Mars showing our mapping regions and the area of 
our mapping coverage (derived from the ArcGIS™ project provided by the USGS). This map shows superposed CTX coverage 
(6 m/pixel, bottom image), which almost fully covers the primary mapping regions (smaller solid black rectangles). Supplemental 
mapping regions include the rift aprons and shield fields (solid white rectangles) and a region of long lava flows (dashed white 
rectangle). 
 
Fig. 3a (below, left). Structural mapping of Arsia Mons superposed on CTX coverage (6 m/pixel) and MOLA color map. Fig. 3b 
(below, right). Structural mapping of Pavonis Mons on the same basemap. Red lines mark the trace of volcanic lava channels 
and/or the traces of lava tubes. Linear features with white diamond symbols mark the locations of linear/sub-linear features that 
could be subvolcanic dikes, medial moraines, and/or eskers. Figures derived from the ArcGIS™ project provided by the USGS. 
 
 
1528.pdf43rd Lunar and Planetary Science Conference (2012)


Geologic Mapping of Arsia and Pavonis Montes

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