OH/H 2 0 Enhancements associated with Some Silicic Volcanism as detected by M 3 Noah Petro LEAG Annual Meeting 2014 October 23, 2014 H/T Carlé Pieters, Rachel Klima, Brad Jolliff, Lillian Ostrach, Tim Glotch, Josh Bandfield
It all starts with Roger Clark Clark et al. (2011) Wet vs. Dry Moon workshop
Bullialdus Crater (Klima et al., 2013) Clark et al. (2011) Wet vs. Dry Moon workshop
OH/H 2 O with M 3 Polar water detection (Pieters et al., 2009; Clark et al., 2012) Bullialdis Central Peak (80 ppm +/- 40 ppm) [Klima et al., 2013]
Compton-Belkovich Lunar Prospector Thorium Thorium enhancement measured by LP Silicic volcanic complex, ~20 x 30 km Morphological evidence for small domes and collapse features Offset of Th due to a pyroclastic eruption? (Jolliff et al., 2011; Wilson et al.,2014?) Alpha Dome
M 3 Perspective: Data taken while Chandrayaan-1 at 200 km M3G20090601T064032 750 nm ~3µm Band Strength Ratio A ratio of two bands (2616µm and 2816 µm, B74/B79) highlights ~3 µm feature.
3µm Absorption at CB Where it is M3G20090601T064032 ~3µm Band Strength Ratio LROC NAC ROI Mosaic -CompBelkLoB 500m
3µm Absorption at CB Where it isn t M3G20090601T064032 ~3µm Band Strength Ratio Alpha Dome Blocky Dome LROC NAC ROI Mosaic -CompBelkLoB 500m
What is at and around 3µm? Pieters et al. 2009 - Model near-infrared reflectance spectra of H 2 O and OH applicable for lunar comparisons. A model of a thin layer of H 2 O water (red) and ice (blue) on a 10% reflective surface equivalent to ~1000-ppm abundance is distinct from anorthite (green) and a lunar glass analog (black). The shaded area extends beyond the spectral range of M 3.
Detection of OH/H 2 O at C-B Stronger 3µm absorption associated with C-B relative to surroundings Strongest absorptions are associated with craters, some seemingly fresh craters, but not all fresh craters Blocky areas have weakest absorptions in region ~3µm Band Depth Ratio LROC NAC ROI Mosaic -CompBelkLoB 500m
What is the origin of the 3µm feature at Compton-Belkovich? Data artifact, the result of thermal correction in the M 3 L2 data Not an artifact: Is there a property of the regolith at C-B relative to its surroundings? Is it due to composition and preferential trapping of OH/H 2 O? Endogenic?
OH/H 2 O in Direct Association with C-B Compton-Belkovich is enhanced in OH/H 2 O relative to its surroundings C-B is indistinct from its surroundings in temperature, rock abundance, and upper regolith thickness (Diviner) 750 nm ~3µm Band Ratio C-B does have a distinct radar signature, is rock-free, consistent with large pyroclastic deposits OH concentration is conservatively ~100-150 ppm above than the surroundings LAMP also sees something in the FUV associated with C-B (Hendrix et al., 2013)
Dufay Albdeo Anomaly Bright diffuse region north of main Thorium enhancement (Dewar) Appears to be thin deposit with some small craters excavating through
Mandel'shtam F 30 km
Diviner CF Map Dufay Albdeo Anomaly Bright diffuse region north of main Thorium enhancement Appears to be thin deposit with some small craters excavating through ~3µm Band Ratio
Dufay Albdeo Anomaly Bright diffuse region north of main Thorium enhancement Appears to be thin deposit with some small craters excavating through ~3µm Band Ratio m3g20081227t090105
Hansteen Alpha Identified in Earth-based spectra as a red spot Glotch et al. (2010) showed that it is silicic Lawrence et al. (2005) modeled a Th abundance of ~25 ppm M3G20090418T190900 Lat: -12.3 Lon: -50.2
M 3 View of Hansteen Alpha A ratio of two bands (2616µm and 2816 µm, B74/B79) M3G20090418T190900_V01_RFL
What is at and around 3µm? Pieters et al. 2009 - Model near-infrared reflectance spectra of H 2 O and OH applicable for lunar comparisons. A model of a thin layer of H 2 O water (red) and ice (blue) on a 10% reflective surface equivalent to ~1000-ppm abundance is distinct from anorthite (green) and a lunar glass analog (black). The shaded area extends beyond the spectral range of M 3.
Is This Feature a Result of the Level 2 Processing?
Is This Feature a Result of the No Level 2 Processing? Feature is there in Level 1B data, pre thermal removal (I/F or Apparent Reflectance) Appears in multiple Optical Periods
What s going on? I m misinterpreting something (as is Klima et al.) We re seeing OH/H 2 O in direct association with silicic volcanic (possibly pyroclastics) at two similar features (C-B and Hansteeen Alpha) and the deposit (pyroclastic?) near Dufay Not all silicic volcanoes (Lassell Massif, Marian Domes) or Th hotspots (SPA) have such features Perhaps a slight enhancement at the Gruithuisen Domes C-B Dufay Hansteen Alpha