geological mapping of the debussy quadrangle (h-14 ... debussy quadrangle contains several features...
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1 1 1 2D. L. Pegg , D. A. Rothery , M. R. Balme , S. J. Conway
Geological Mapping of the Debussy Quadrangle (H-14): Preliminary Results
1School of Physical Sciences, The Open University, Milton Keynes, MK7 6AA, UK2CNRS, Laboratoire de Planétologie et Géodynamique, Université de Nantes, France
The Debussy quadrangle contains several features of geological interest. Rembrandt basin is the second largest well
defined basin on Mercury. The quadrangle also hosts the older [8]and subtler basin B34 which is partially obscured by the
Debussy impact crater. The two largest lobate scarps within the quadrangle are Enterprise
and Belgica Rupes which bound a [9]large wavelength fold .
References [1] Galluzzi V. and BC Mapping team., 2017, 5th BepiColombo SWT Meeting. [2] Guzzetta, L., et al.,
2017, J of Maps 13.2, 227-238. [3] Galluzzi, V., et al., 2016, J of Maps 12.1, 227-238. [4] Wright J., et al., This meeting, #6062. [5] Mancinelli, P., et al. 2016, J of Maps 12, 190-202. [6] Malliband C.C., et al., This meeting [#6091]. [7] Tanaka K.L. et al. 2011. USGS. [8] Fassett, C. I. et al. 2012, JGR, 117: E00L08. [9] Watters, T. R., et al., 2016 Geophysical Research Letters, 43.22. [10] McCauley, J. F., 1981. Icarus, 47(2), 184–202. [11] Kinczyk, M. J., et al., 2016, LPSC, #1573. [12] Hynek, B. M., et al. 2016, LPSC. Vol. 47.
Using MESSENGER data, including the 166 m/pixel global photomosaics and [7]following USGS mapping standards , line work is undertaken at a scale of 1:300,000.
Crater rims have been outlined and identification of wrinkle ridges and scarps is underway (fig. 2). Craters with a diameter larger than 20 km are being classified based on
degradation state, floors categorised based on morphology and any ejecta outlined. Characterisation of the plains surrounding the craters has started.
I would like to acknowledge the STFC for funding my studentship (grant number: ST/R504993/1) and also thank USRA/LPI for the travel award enabling me to attend the Mercury: Current and Future Science of the Innermost Planet meeting.
XW Hollow Clusters
XW Pyroclastic Deposits
Crater Class 3
Crater Class 2
Crater Class 1
Crater Floor Hummocky
Crater Floor Smooth
Smooth Plains
Intercrater Plains
In order to prepare for BepiColombo an understanding of the geology of the planet needs to be built up. Geology maps are being produced of the whole
[1]globe at a scale of 1:3M (fig. 1). H-14, the Debussy quadrangle, in the southern hemisphere, is the latest to be mapped. Always on the nightside during the Mariner 10 flybys, it was first observed by NASA’s MESSENGER mission during its second flyby in 2008 revealing some exciting geological features.
Class 3 craters are the least degraded and so assumed to be youngest. They have clear well preserved rims and central peaks with clear terracing in complex craters. On the largest of these bright ejecta rays are still observed (fig. 3).
Class 2 craters show some signs of degredation. they still have continuous rims but the central peaks are eroded and only proximal ejecta is obvious (fig. 3).
Class 1 craters are the oldest and most degraded on the surface. The rim is highly degraded and pockmarked. The central peaks and peak ring are mostly absent, ejecta is not clear (fig. 3).
A 3 class system for recording crater degradation is being used currently to match the other maps so far completed at
[3]the same scale . This system does not purport to represent the ages of craters due to the expected d i f fe rent ra tes o f degradation of features for different crater sizes.
The 5 class system which is used on the global [10,11]maps will also be used enabling compatibility
with MESSENGER products.
a
b
C3
C2
C1
C3
C2
C1
Published In progress This quadrangle
H-02 Victoria
H-03Shakespeare
H-06Kuiper
H-07Beethoven
H-11Discovery
H-14 Debussy
H-05Hokusai
Figure 1: Status of 1:3 millon geological mapping project
Figure 2: Current (incomplete) map of Debussy quadrangle
Plains material will be identified in between the crater materials. Smooth
Plains and Intercrater Plains have so far been identified. Elsewhere on Mercury Intermediate Plains have been mapped as well as units
[5,10]specific to the ‘Caloris’ impact basin . It is expected that units distinct to the Rembrandt basin will be delineated in due course as seen in other
[12]maps of the basin .
Smooth Plains are gently rolling units with fewer impact craters, they tend to have sharp contacts with adjacent units. They are often confined to basins, crater floors and low-lying areas. Wrinkle ridges and embayed craters can often be found in these units and are thought to be relatively young lavas (fig. 4a).
Intercrater Plains are comprised of undulating and hummocky plains that have a high density of <10 km craters, these are thought to represent some of the oldest remaining surfaces on the planet. These plains dominate the southern hemisphere and it is expected to cover much of the quadrangle away from impact basins (fig. 4b).
Figure 4: a. Smooth Plains w i th in Rembrandt . b . Intercrater Plains from the north of the quadrangle
Figure 3: Examples of different degradation states of craters from within H-14
H-10 Derain
> 20 km Craters
> 5 km Craters
Crater Rim Buried
Contact Approximate
Contact Certain
Fault Certain
Fault Uncertain
Graben Uncertain
Pit
+ Thrust Certain
+ Thrust Uncertain
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