Geological mapping of the Hokusai (H05) quadrangle of Mercury: Status update Jack Wright1, David A. Rothery1, Matt R. Balme1, Susan J. Conway2 1School of Physical Sciences, The Open University, Milton Keynes, MK7 6AA, UK [email protected] 2CNRS, Laboratoire de Planétologie et Géodynamique, Université de Nantes, France @wrightplanet 1. Status update 3. Resurfacing modes and timings? 180° H01 Mariner 10 MESSENGER data are being 270° North Pole 90° The first global geological map of Mercury has two used to construct 1:3M-scale Borealis MESSENGER Fig. 1. Mercury geomorphic plains units: smooth and intercrater plains mapping quadrangles. geological maps of Mercury [1– 0° [9]. On quadrangle maps, these can be subdivided, 66° 66° Mariner 10 maps are 6] (Fig. 1). These will provide H03 H02 H05 H04 being superseded by adding information about geological processes. Below 180° Shakespeare 270° Victoria 0° Hokusai 90° Raditladi 180° context and science targets for MESSENGER maps. are important plains types within Hokusai. 21.5° 21.5° the ESA/JAXA BepiColombo H02, H03 and H04 are 35°E 40°E 45°E mission to Mercury [7]. We H08 H07 H06 H10 H09 H08 published [1–3]. H05, Fig. 3. Low density of Tolstoj Beethoven Kuiper Derain Eminescu Tolstoj superposing impact present the first geological map -21.5° -21.5° H06, H07, H10 and H14 are underway [4–6]. craters. Sharp of the Hokusai (H05) quadrangle 180° 270° 0° 90° 180° H12 H11 H14 H13 H08 and H11 are contacts with adjacent Michaelangelo Discovery Debussy Neruda 60°N ± (Fig. 2). Mapping within Borealis scheduled [4]. H01 is units. Abundant Planitia is complete. Mapping is -66° 0° -66° being mapped in a wrinkle ridges, some progressing in the south- H15 separate effort [8]. forming rings 10s– 270°South Pole 90° western cratered plains. Bach 100s km across indicating impact 180° SMOOTH craters buried by 100km 'smooth plains' [9,10] multiple lava flows. 2. Geological map of Hokusai quadrangle 35°E 40°E Fig. 4. More textured Geological units 0° 10°E 30°E 50°E 70°E 90°E Crater rims plains containing smooth plains 0° crest of subdued or buried crater 70°N 10°E 90°E 70°N isolated patches of intercrater plains crest of crater rim (diam. > 20km) smooth plains within 30°E 70°E ± smooth crater infill 50°E crest of small crater rim (diam. > 5km) low-lying regions hummocky crater infill 30°N (e.g., secondary pyroclastic deposits Structures crater chains). Occurs Crater materials 60°N 60°N irregular pit crater graben close to typical c3 (fresh) wrinkle ridge ring smooth plains. c2 Hokusai crater ridge Widespread in SE c1 (degraded) Rustaveli wrinkle ridge 100km H05. 50°N 50°N Borealis Planitia 8°E 10°E 40°N 40°N Fig. 5. Plains containing abundant ± flat-floored craters 28°N with degraded rims. 30°N 30°N Intervening smooth patches 10s of km across. Widespread in Unity Rupes SW H05. 20°N 20°N 50km Rachmaninoff 'intercrater plains' [9,10] 26°N 20°E 0° 90°E Fig. 6. Plains with abundant, relatively 10°E 80°E immature secondary ± craters from nearby 25°N Contacts 20°E 70°E Faults primary impacts. No contact (certain) 30°E 60°E fault (uncertain) smooth patches. contact (uncertain) 40°E 50°E + + thrust (certain) Diffuse contacts. km Least widespread 0 250 500 1,000 1,500 2,000 CRATERED 'intercrater plains' Fig. 2. Current status of geological map of H05. ~1:7M scale. Transparent geological units overlain on MESSENGER ~166 meters sub-type in H05. per pixel global monochrome mosaic basemap. 5° overlap with surrounding quadrangles for boundary matching at a later date. 50km References: [1] Galluzzi V. et al. (2016) J. Maps, 12, 227–238. [2] Guzzetta L. et al. (2017) J. Maps, 13, 227–238. [3] Mancinelli Acknowledgements: JW is funded by UK P. et al (2016), J. Maps, 12, 190–202. [4] Galluzzi V. et al. (2018) Mercury: Current and Future Science of the Innermost Planet, Science and Technology Facilities Council Abstract #6075. [5] Malliband C. C. et al. (2018) Mercury: Current and Future Science of the Innermost Planet, Abstract #6091. (STFC) training grant ST/N50421X/1. JW is [6] Pegg D. L. et al. (2018) Mercury: Current and Future Science of the Innermost Planet, Abstract #6021. [7] Benkhoff J. et al. grateful to the Lunar and Planetary Science (2010) Planet. Space Sci., 58, 2–20. [8] Ostrach L. R. et al. (2018) LPS XLIX, Abstract #1747. [9] Kinczyk M. J. et al. (2018) Institute (LPI) for granting him a 2018 LPI Mercury: Current and Future Science of the Innermost Planet, Abstract #6123. [10] Whitten J. L. et al. (2014) Icarus, 241, 97– Career Development Award to attend the 49th 113. LPSC. SJC is supported by CNES..