adsabs/AstroCLIMB huggingface dataset:
Paper: Local-time Dependence of Chemical Species in the Venusian Mesosphere
Authors: Wencheng D. Shao, Xi Zhang, João Mendonça, and Thérèse Encrenaz
Figure caption: Local-time dependence of (a) temperature anomalies Tanomaly, (b) vertical velocity W, (c) SO2 mixing ratio, (d) SO2 chemical loss timescale tChemical, (e) transport timescale tTransport, and (f) ratio of tTransport to tChemical. The wind field (m s−1) is superposed on panel (b). Temperature and wind fields are from the OASIS simulations (Mendonça & Buchhave 2020), and the SO2 mixing ratios are from the 2D CTM. Temperature anomaly is the deviation from an average temperature profile shown in Figure C1. Note that both the 2D CTM and OASIS use (log-)pressure coordinates. Height at the vertical axis in this plot represents the isobaric level and is derived from pressure by using the VIRA model (see Table 1 of Mendonça & Read 2016). The local time 06:00 is the morning terminator, 18:00 is the evening terminator, 12:00 is noon, and 00:00 is midnight. Earlier local time means eastward shift on Venus. The ratio of tTransport to tChemical indicates the main driven mechanism for the species distribution: the ratio smaller than unity (blue region in panel (f)) implies a mainly transport-driven regime; the ratio larger than unity (red region in panel (f)) implies a mainly photochemistry-driven regime; the ratio around unity (white region in panel (f)) implies the transition between the two regimes.
Paper: Local-time Dependence of Chemical Species in the Venusian Mesosphere
Authors: Wencheng D. Shao, Xi Zhang, João Mendonça, and Thérèse Encrenaz
Figure caption: Local-time distributions of (a) vertical velocity, (b) SO2 mixing ratio, and (c) zonal velocity around 64 km. Observational data (error bars) in panel (b) are from TEXES/IRTF (Encrenaz et al. 2020). Positive vertical velocity is upward, and negative zonal velocity is westward.
Paper: Local-time Dependence of Chemical Species in the Venusian Mesosphere
Authors: Wencheng D. Shao, Xi Zhang, João Mendonça, and Thérèse Encrenaz
Figure caption: Local-time dependence of (a) CO mixing ratio, (b) CO chemical loss timescale tChemical, and (c) ratio of tTransport to tChemical.
Paper: Local-time Dependence of Chemical Species in the Venusian Mesosphere
Authors: Wencheng D. Shao, Xi Zhang, João Mendonça, and Thérèse Encrenaz
Figure caption: Vertical profiles of (a) CO mixing ratio and (b) zonal wind at different local times. Altitude derived from the VIRA model is shown on the right axis. The gray dashed line in panel (a) encloses a region corresponding to a rough range of the observations by Vandaele et al. (2016). The blue dashed line in panel (b) is zero zonal wind.
Paper: Local-time Dependence of Chemical Species in the Venusian Mesosphere
Authors: Wencheng D. Shao, Xi Zhang, João Mendonça, and Thérèse Encrenaz
Figure caption: Same as Figure 3, but for H2O.
Paper: Local-time Dependence of Chemical Species in the Venusian Mesosphere
Authors: Wencheng D. Shao, Xi Zhang, João Mendonça, and Thérèse Encrenaz
Figure caption: Same as Figure 3, but for HCl.
Paper: Local-time Dependence of Chemical Species in the Venusian Mesosphere
Authors: Wencheng D. Shao, Xi Zhang, João Mendonça, and Thérèse Encrenaz
Figure caption: Same as Figure 3, but for ClO.
Paper: Local-time Dependence of Chemical Species in the Venusian Mesosphere
Authors: Wencheng D. Shao, Xi Zhang, João Mendonça, and Thérèse Encrenaz
Figure caption: Same as Figure 3, but for OCS.
Paper: Local-time Dependence of Chemical Species in the Venusian Mesosphere
Authors: Wencheng D. Shao, Xi Zhang, João Mendonça, and Thérèse Encrenaz
Figure caption: Same as Figure 3, but for SO.
Paper: Local-time Dependence of Chemical Species in the Venusian Mesosphere
Authors: Wencheng D. Shao, Xi Zhang, João Mendonça, and Thérèse Encrenaz
Figure caption: Local-time variations of volume mixing ratios of SO2, SO, and OCS from both our model and observations (Figure 11(b) of Belyaev et al. 2017; Sandor et al. 2010; Krasnopolsky 2010). Note that the observation altitude is not necessarily exactly the value shown in this plot (refer to Table 2 to see the observation altitude range).
Paper: Local-time Dependence of Chemical Species in the Venusian Mesosphere
Authors: Wencheng D. Shao, Xi Zhang, João Mendonça, and Thérèse Encrenaz
Figure caption: Chemical lifetimes of (a) SO2, (b) CO, and (c) SO if the fast cycles in Appendix B are included. Panels (d)–(f) are the ratios of tTransport to tChemical for the three species when the fast cycles are included.
Paper: Local-time Dependence of Chemical Species in the Venusian Mesosphere
Authors: Wencheng D. Shao, Xi Zhang, João Mendonça, and Thérèse Encrenaz
Figure caption: Average temperature profile simulated by our GCM (black) and VIRA temperature profile (blue). The temperature anomaly in Figure 1 is the deviation from this GCM’s average temperature profile.
Paper: Local-time Dependence of Chemical Species in the Venusian Mesosphere
Authors: Wencheng D. Shao, Xi Zhang, João Mendonça, and Thérèse Encrenaz
Figure caption: Local-time distributions of SO2 mixing ratio at different altitudes for different cases: (a) our nominal case (black); (b) cases with Kzz enlarged by 1.5 (blue) and 2.0 (red); (c) cases with Kxx changed by a factor of 0.1 (green) and 10.0 (cyan); (d) cases with a higher (double) horizontal resolution (magenta). Note that green, cyan, and black lines are almost overlapping with each other. In panel (d), error bars show observations at 95–100 km from SPICAV/VEx by Belyaev et al. (2017) and observations at 70–100 km from JCMT by Sandor et al. (2010).
Paper: Local-time Dependence of Chemical Species in the Venusian Mesosphere
Authors: Wencheng D. Shao, Xi Zhang, João Mendonça, and Thérèse Encrenaz
Figure caption: Same as Figure C2, but for CO.
Paper: Local-time Dependence of Chemical Species in the Venusian Mesosphere
Authors: Wencheng D. Shao, Xi Zhang, João Mendonça, and Thérèse Encrenaz
Figure caption: Same as Figure C2, but for H2O.
Paper: Local-time Dependence of Chemical Species in the Venusian Mesosphere
Authors: Wencheng D. Shao, Xi Zhang, João Mendonça, and Thérèse Encrenaz
Figure caption: Same as Figure C2, but for HCl.
Paper: Local-time Dependence of Chemical Species in the Venusian Mesosphere
Authors: Wencheng D. Shao, Xi Zhang, João Mendonça, and Thérèse Encrenaz
Figure caption: Same as Figure C2, but for ClO.
Paper: Local-time Dependence of Chemical Species in the Venusian Mesosphere
Authors: Wencheng D. Shao, Xi Zhang, João Mendonça, and Thérèse Encrenaz
Figure caption: Same as Figure C2, but for OCS. In panel (a), gray bars show a few observation points near 65 km from CSHELL/IRTF by Krasnopolsky (2010).
Paper: Local-time Dependence of Chemical Species in the Venusian Mesosphere
Authors: Wencheng D. Shao, Xi Zhang, João Mendonça, and Thérèse Encrenaz
Figure caption: Same as Figure C2, but for SO. In panel (d), error bars show observations at 70–100 km from JCMT by Sandor et al. (2010).
Paper: The Extent, Nature, and Origin of K and Rb Depletions and Isotopic Fractionations in Earth, the Moon, and Other Planetary Bodies
Authors: Nicolas Dauphas, Nicole X. Nie, Marc Blanchard, Zhe J. Zhang, Hao Zeng, Justin Y. Hu, Merlin Meheut, Channon Visscher, Robin Canup, and Timo Hopp
Figure caption: Evaporation timescales for reaching Moon-like depletions for Na in the model of Charnoz et al. (2021) of tidally driven hydrodynamic escape from the LMO. Here we focus on the evaporation step involving transfer of Na (panel (a)) and K (panel (b)) from the LMO to the lunar atmosphere, not transport in the hydrodynamic wind. While hydrodynamic escape may have been channeled along the line connecting the centers of Earth and the Moon (Charnoz et al. 2021), transfer to the atmosphere could have taken place over a wider surface area, and we conservatively calculate the evaporation flux over the whole lunar surface area (a solid angle of 4π sr). The oxygen fugacity is buffered by BSE liquid (Visscher & Fegley 2013; Canup et al. 2015; Equation (30)), the same assumption that was made by Charnoz et al. (2021). The blue solid curves are from this study, using the parameterization for γΓ from Zhang et al. (2021, Equations (31) and (32)) and a vapor saturation S = 0.99 (see text for details; also see Nie & Dauphas 2019). The black solid lines were calculated using the equilibrium vapor pressure from Canup et al. (2015) for K (﹩P{{\rm{K}}}_{\mathrm{eq}}={10}^{-4.7\times {10}^{6}/{T}^{2}-11935/T+1.5825}﹩, with PKeq in bar and T in K) and Visscher & Fegley (2013) for Na (﹩P{{\rm{Na}}}_{{\rm{eq}}}={10}^{(-4.5e6/{T}^{2}-11629/T+3.0586)}﹩), S = 0.99, and evaporation coefficients γ of 0.1 (Alexander 2002; Fedkin et al. 2006; Richter et al. 2011; Zhang et al. 2021). The dashed red lines were calculated by using the thermodynamic data provided by Charnoz et al. (2021) and assuming S = 0.99 and γ = 0.1. As shown, the calculated evaporation timescales at 1700 K (the temperature preferred by Charnoz et al. 2021) are all orders of magnitude longer than the lifetime of the exposed LMO (>0.8 Myr for K and >1.2 Myr for Na, compared to ∼1000 yr for the LMO). The only way that we have found to decrease the evaporation timescales to values comparable to the lifetime of the exposed LMO is by taking S = 0.8 and γ = 1 and using the digitized K and Na equilibrium vapor pressures from Figure 14 of Charnoz et al. (2021). However, isotopic data call for evaporation in a near-saturated medium (S = 0.99; this study; Nie & Dauphas 2019; Charnoz et al. 2021), free evaporation experiments support an evaporation coefficient of γ = 0.1 (Alexander 2002; Fedkin et al. 2006; Richter et al. 2011; Zhang et al. 2021), and the K and Na equilibrium vapor pressures plotted in Figure 14 of Charnoz et al. (2021) are inconsistent with the thermodynamic data that accompany this figure.
Paper: The Extent, Nature, and Origin of K and Rb Depletions and Isotopic Fractionations in Earth, the Moon, and Other Planetary Bodies
Authors: Nicolas Dauphas, Nicole X. Nie, Marc Blanchard, Zhe J. Zhang, Hao Zeng, Justin Y. Hu, Merlin Meheut, Channon Visscher, Robin Canup, and Timo Hopp
Figure caption: Measured isotopic fractionations between the Moon and BSE in δ notation against predictions for fractional equilibrium condensation at 3500 K (Equation (35); Section 4.3). The model predictions correspond to what would be expected for the models of MVE depletion of Canup et al. (2015) and Lock et al. (2018), where MVE depletion happens very soon after the giant impact owing to incomplete condensation at high temperature and loss of MVEs to Earth.
Paper: The Extent, Nature, and Origin of K and Rb Depletions and Isotopic Fractionations in Earth, the Moon, and Other Planetary Bodies
Authors: Nicolas Dauphas, Nicole X. Nie, Marc Blanchard, Zhe J. Zhang, Hao Zeng, Justin Y. Hu, Merlin Meheut, Channon Visscher, Robin Canup, and Timo Hopp
Figure caption: Planetary depletions in K and Rb in planetary materials (see text and Table 1 for details). Because Sr and U are two refractory lithophile elements, K/U and Rb/Sr ratios normalized to CI (Ivuna-type) chondrite are direct measures of the depletions in MVEs K and Rb (Halliday & Porcelli 2001; Davis 2006). (a) K/U vs. Rb/Sr in the angrite parent body (APB), the Moon, Vesta (HED meteorites), Earth, Mercury, Mars (SNC meteorites), and CV, CO, CM, CI, LL, L, H, EL, and EH chondrites (listed from the most volatile-element-depleted to the most volatile-element-enriched objects). The diagonal line corresponds to equal depletions in K and Rb. (b) Relative volatilities of K and Rb. While to first order the two elements show similar depletions (panel (a)), in detail Rb appears to be more volatile than K such that the most volatile-element-depleted objects display K/Rb ratios that are higher than CI.
Paper: The Extent, Nature, and Origin of K and Rb Depletions and Isotopic Fractionations in Earth, the Moon, and Other Planetary Bodies
Authors: Nicolas Dauphas, Nicole X. Nie, Marc Blanchard, Zhe J. Zhang, Hao Zeng, Justin Y. Hu, Merlin Meheut, Channon Visscher, Robin Canup, and Timo Hopp
Figure caption: Estimates of the BSE K/U and Rb/Ba ratios. Three databases were used to estimate those ratios: mid-oceanic ridge basalts (MORB; Gale et al. 2013), Oceanic Islands (OI; PetDB query), and Continental Crust and a small proportion of modern Island Arc samples (CC+IA; Ptáček et al. 2020). We select from those databases the samples that contain concentration data for K, Rb, Ba, Th, U, Ta, Nb, and La. We then normalize the concentrations of refractory lithophile incompatible elements Ba, Th, U, and La to CI chondrite composition (Barrat et al. 2012) and calculate the relative standard deviation (RSD) of those four normalized concentrations. Samples containing Ba, Th, U, and La in near-CI proportions will have RSDs (Equation (1)) near zero (the incompatible element pattern is labeled as “flat” if the samples are among the 2.5% with the lowest RSD), while those with fractionated or imprecise concentrations will have high RSD. Refractory lithophile elements are expected to be in chondritic proportions in the BSE. Panels (a) and (b) show how K/U and Rb/Ba weight ratios converge to values of 9845 ± 2054 and 0.0787 ± 0.0157, respectively, as defined by the 2.5% samples with the lowest RSD (corresponding to a K/Rb ratio of 386 ± 109). Panels (c) and (d) show the joint distributions of K/U-La/U and Rb/Ba-Th/Ba (like U, La is often taken as a proxy to K during mantle melting; Th is highly incompatible like Ba and Rb). The red filled circles are the 2.5% samples with the lowest RSD, and the red filled diamond is our best estimate for the BSE. As shown, the CI-normalized La/U and Th/Ba ratios of the low-RSD samples are evenly distributed around unity, and no correlation is seen between K/U-La/U or Rb/Ba-Th/Ba, so there is no indication that our estimate could be biased. Panel (e) shows which samples belong to the group with flat incompatible Ba-Th-U-La pattern. Although we do not select against differentiated igneous rocks, almost all the samples in the “flat” subgroup are basalts. Panel (f) shows that the K/U and K/Rb ratios of samples with flat Ba-Th-U-La pattern correlate. The slightly lower K/Rb and K/U of OIBs might be due to recycling of altered oceanic crust.
Paper: The Extent, Nature, and Origin of K and Rb Depletions and Isotopic Fractionations in Earth, the Moon, and Other Planetary Bodies
Authors: Nicolas Dauphas, Nicole X. Nie, Marc Blanchard, Zhe J. Zhang, Hao Zeng, Justin Y. Hu, Merlin Meheut, Channon Visscher, Robin Canup, and Timo Hopp
Figure caption: Comparison between this study (Table 1; red filled circles with error bars) and literature estimates of K/U and Rb/Sr ratios in the BSE and bulk silicate Moon. Our estimates rely on geochemical similarities between Rb-Ba-Th and K-U-La by focusing on samples that have near-chondritic proportions of refractory lithophile elements Ba-Th-U-La (low-RSD samples; Figures 2, 4) or for the Moon by interpolating Rb/Ba-Th/Ba and K/U-La/U correlations to chondritic Th/Ba and La/U ratios (Figure 4). (a) K/U ratio of BSE; mostly estimated assuming constant K/U or K/La ratios (Gast 1960; Heier & Rogers 1963; Wasserburg et al. 1964; Hurley 1968; Larimer 1971; Shaw 1972; Ganapathy & Anders 1974; Smith 1977; O’Nions et al. 1978; Jacobsen & Wasserburg 1979; Jagoutz et al. 1979; Armstrong 1981; Sun 1982; Anderson 1983; Jochum et al. 1983; McDonough & Sun 1995; Allègre et al. 2001; Lassiter 2004; Lyubetskaya & Korenaga 2007; Arevalo et al. 2009; Palme & O’Neill 2014; Farcy et al. 2020; O’Neill et al. 2020). (b) K/U ratio of the bulk Moon; mostly estimated assuming constant K/U or K/La ratios (LSPET 1969; Tera et al. 1970; Larimer 1971; Ganapathy & Anders 1974; Morgan et al. 1978; Wänke 1981; Taylor 1982; O’Neill 1991; McDonough et al. 1992; Warren 2005; Taylor & Wieczorek 2014; Albarède et al. 2015). (c) Rb/Sr ratio of BSE; after 1976 often estimated from 87Sr-143Nd systematics (Gast 1960; Hurley 1968; Larimer 1971; Shaw 1972; Ganapathy & Anders 1974; DePaolo & Wasserburg 1976; Jahn & Nyquist 1976; O’Nions et al. 1977; Smith 1977; O’Nions et al. 1978; Allègre et al. 1979; Jacobsen & Wasserburg 1979; Jagoutz et al. 1979; Armstrong 1981; Sun 1982; Anderson 1983; Hofmann & White 1983; McDonough et al. 1992; McDonough & Sun 1995; Allègre et al. 2001; Lyubetskaya & Korenaga 2007; McDonough & Arevalo 2008; Palme & O’Neill 2014). (d) Rb/Sr ratio of bulk silicate Moon; mostly estimated assuming constant Rb/Ba ratio (Larimer 1971; Ganapathy & Anders 1974; Morgan et al. 1978; Taylor 1982; O’Neill 1991; McDonough et al. 1992; Taylor & Wieczorek 2014; Albarède et al. 2015).
Paper: The Extent, Nature, and Origin of K and Rb Depletions and Isotopic Fractionations in Earth, the Moon, and Other Planetary Bodies
Authors: Nicolas Dauphas, Nicole X. Nie, Marc Blanchard, Zhe J. Zhang, Hao Zeng, Justin Y. Hu, Merlin Meheut, Channon Visscher, Robin Canup, and Timo Hopp
Figure caption: Correlations between K/U-La/U, Rb/Ba-Th/Ba, and K/Rb-U/Ba in lunar basalts (blue circles) and KREEP-rich soils and breccias from Apollo 14 (yellow circles). All these elements (K, Rb, Ba, Th, U, and La) are highly incompatible during partial melting and magmatic differentiation. The purple diamonds are calculated compositions for a model of LMO crystallization corresponding to (1) the KREEP liquid after 95% LMO crystallization and (2) a mixture of 98% mafic cumulate+1% plagioclase+1% KREEP liquid that would be representative of the source of mare basalts (Snyder et al. 1992; see text for details). As shown, the calculated KREEP and mare basalt compositions fall within the range of compositions measured in lunar samples, supporting the view that the trends depicted in this diagram reflect LMO differentiation and more specifically plagioclase flotation. Ba, Th, La, and U are highly refractory elements, and the La/U, Th/Ba, and U/Ba ratios are expected to be approximately chondritic (CI-like) in bulk planetary objects. Extrapolating the K/U vs. La/U relationship (a) to a CI-like La/U ratio yields a bulk lunar K/U weight ratio of 2448 ± 140 g g−1. Similarly, extrapolating the Rb/Ba vs. Th/Ba relationship (b) to a CI-like Th/Ba ratio yields a bulk lunar Rb/Ba weight ratio of 0.0167 ± 0.0018 g g−1. Combining the bulk Moon K/U and Rb/Ba ratios yields a bulk Moon K/Rb ratio of 459 ± 56 g g−1, consistent with the values measured in lunar samples with U/Ba ratios close to the CI value. The estimated bulk lunar weight ratios are displayed as red squares. Another approach to estimating bulk Moon K/U, Rb/Ba, and K/Rb ratios is to focus on samples that have Ba, Th, U, and La in near-chondritic proportions. The degree to which the samples depart from CI proportions is quantified using the RSD of the CI-normalized abundances of these elements (100 RSD; Equation (1); the samples highlighted with thick contours are the 25% with the lowest RSD). As shown, the samples with low RSD have K/U (D), Rb/Ba (E), and K/Rb (F) ratios that are scattered around the bulk Moon values inferred from the regressions depicted in panels (a) and (b). The data were compiled from the LSC (Meyer 2012). The mare basalt samples are all those for which K, Rb, Ba, La, and U data are reported in the compendium (n = 113). The Apollo 14 KREEP-rich samples are those used by Warren & Wasson (1979) to define the KREEP end-member composition and for which bulk K, Rb, Ba, and U data are reported in the compendium (n = 8; samples 14148–14149–14156, 14163, 14006, 14141, 14305, 14301, 14303, 14321).
Paper: The Extent, Nature, and Origin of K and Rb Depletions and Isotopic Fractionations in Earth, the Moon, and Other Planetary Bodies
Authors: Nicolas Dauphas, Nicole X. Nie, Marc Blanchard, Zhe J. Zhang, Hao Zeng, Justin Y. Hu, Merlin Meheut, Channon Visscher, Robin Canup, and Timo Hopp
Figure caption: Comparison between La-U-Th-Ba-Rb data from the LSC (Meyer 2012) and high-precision ICPMS data from Neal (2001). There are 120 entries in our mare basalt+KREEP compilation from the LSC that were measured by a variety of techniques (e.g., OES, NAA, IDMS, XRF, radiation counting, ICPMS, wet chemical analysis, AAS), including some that have relatively low precision and high detection limit. Neal (2001) reported analyses of the compositions of 65 mare basalts by the technique of ICPMS, which has high precision and low detection limit. K2O was not measured in Neal (2001), and the values used here are all averages from the LSC. Panels (a)–(c) are like panels (a)–(c) from Figure 4, but using only the ICPMS data from Neal (2001). The red lines are the regressions through the whole LSC data set, and the red squares are our best estimates of bulk silicate Moon values (Figures 4(a)–(c)). As shown, the data from Neal (2001) are consistent with the LSC compilation, and data scatter is not improved by using only ICPMS data. Panels (d)–(i) compare elemental ratios obtained by ICPMS from single aliquots (Neal 2001) (x-axis) with ratios for the same rocks calculated by taking averages of concentrations reported in various studies compiled in the LSC (obvious outliers were excluded from sample averages) but excluding ICPMS data from Neal (2001) (y-axis). The dashed lines are 1:1. As shown, non-ICPMS data compiled from the LSC agree with ICPMS data from Neal (2001).
Paper: The Extent, Nature, and Origin of K and Rb Depletions and Isotopic Fractionations in Earth, the Moon, and Other Planetary Bodies
Authors: Nicolas Dauphas, Nicole X. Nie, Marc Blanchard, Zhe J. Zhang, Hao Zeng, Justin Y. Hu, Merlin Meheut, Channon Visscher, Robin Canup, and Timo Hopp
Figure caption: Maps of K/Th ratio normalized to the BSE value (top panel) and K concentration normalized to the maximum value (bottom panel). Far-side K/Th values show more noise owing to lower K and Th concentrations, but the K/Th ratio is the same on the near and far sides. K depletion is a global feature of the Moon. Data from Lunar Prospector (Feldman et al. 1998; Lawrence et al. 1998).
Paper: The Extent, Nature, and Origin of K and Rb Depletions and Isotopic Fractionations in Earth, the Moon, and Other Planetary Bodies
Authors: Nicolas Dauphas, Nicole X. Nie, Marc Blanchard, Zhe J. Zhang, Hao Zeng, Justin Y. Hu, Merlin Meheut, Channon Visscher, Robin Canup, and Timo Hopp
Figure caption: Potassium depletion at the lunar surface. (a) K/Th ratio as a function of great-circle distance from the center of the Procellarum basin (data from Lunar Prospector; Lawrence et al. 1998; Feldman et al. 1998). As shown, the depletion in K (normalized to refractory lithophile incompatible element Th) is uniform across the lunar surface. (b) K concentration as a function of great-circle distance from the center of the Procellarum basin. The KREEP region and its antipode in the South Pole–Aitken basin show less dispersion owing to higher K and Th concentrations (Figure 6 bottom panel). (c) K/U vs. La/U ratio diagram for lunar meteorites, which sample a more representative area of the Moon, including the far side (data compiled from the lunar meteorite compendium). Lunar meteorites show the same level of K depletion as what is seen in Apollo mare basalts, demonstrating that the latter are not biased by their belonging to the Procellarum basin.
Paper: The Extent, Nature, and Origin of K and Rb Depletions and Isotopic Fractionations in Earth, the Moon, and Other Planetary Bodies
Authors: Nicolas Dauphas, Nicole X. Nie, Marc Blanchard, Zhe J. Zhang, Hao Zeng, Justin Y. Hu, Merlin Meheut, Channon Visscher, Robin Canup, and Timo Hopp
Figure caption: Evaluation of the degree of K and Rb depletions in Mars. The data points represent the compositions of SNC meteorites (Lodders 1998). The K/U and Rb/Ba ratios of Mars are calculated (red squares) by interpolating the data to CI chondrite La/U (panel (a)) and Th/Ba (panel (b)) ratios. The K/Rb ratio calculated from those interpolations and assuming a CI U/Ba ratio is consistent with the K/Rb ratio measured in SNC meteorites (panel (c)).