Titanium abundance data

In some cases, thermal neutrons can also be used to measure the absolute abundances of other elements. Transforming the neutron spectrum into elemental abundances can be quite involved. For example, to determine the titanium abundances in lunar spectra, Elphic et at. (2002) first had to obtain FeO estimates from Clementine spectral reflectances and Th abundances from gamma-ray data, and then estimate the abundances of the rare earth elements gadolinium and samarium from their correlations with thorium. They then estimated the absorption of neutrons by major elements using the FeO data and further absorption effects by gadolinium and samarium, which have particularly large neutron cross-sections. After making these corrections, the residual neutron absorptions were inferred to be due to titanium alone. 

New phosphoms and titanium XRF data for Cl chondrites were reported by Wolf and Palme (2001). The change in phosphorus is significant. The new Cl abundance is 926 ppm, which is much lower than the values in the older compilations, 1,105 ppm in Palme and Beer (1993) and 1,200 ppm in Anders and Grevesse (1989), respectively. The new phosphorus contents are considered to be more reliable. The changes in titanium are small. Wolf and Palme (2001) also reported major element concentrations of Cl meteorites and other carbonaceous chondrites. Their magnesium and silicon contents were almost identical to those given by Palme and Beer (1993) 10.69% versus 10.68% (for silicon) in Palme and Beer (1993) and 9.60% versus 9.61 % (for magnesium) in Palme and Beer (1993). The aluminum, calcium, and iron concentrations... 

Figure 10 Chondrite-normalized REE concentrations in mare basalts, KREEP, and a representative ferroan anorthosite. Data for mare basalt t)fpes are from Table 2, with two deliberate omissions the NWA773 cumulate, an individual rock presumably unrepresentative of its parent magma, and the Apollo 14 t)fpe, which is a suite with notoriously diverse REE abundances, although the patterns are generally parallel to KREEP (which is plotted). Individual mare basalt types are not labeled, but symbols on some of the patterns denote relatively titanium-rich varieties the most titanium-rich basalts (largest symbols) tend to have the lowest (often subchondritic) La/Sm ratios. Data for high-K KREEP and ferroan anorthosite 15295c41 are from Table 5 and Warren et al. (1990), respectively.

Figure 13 Trace-element ratios in IDPs. Data from synehrotron X-ray fluoreseenee analyses are plotted on three element diagrams. Element ratios are normalized to bulk Cl abundances (element/Fe)sampie/(element/Fe)ci also denoted element/Fe/CL Cl eomposition lies at the point element/Fe/CI = 1 on eaeh plot. Averages, assuming data are normally distributed (open squares) and assuming the data are log normally distributed (open diamonds), are also shown. Plots (a)-(c) exhibit the behavior of some more refractory elements chromium, calcium, and titanium with respect to nickel, while (d) and (e) show the behavior of zine (relatively volatile) with respect to nickel (relatively refractory) and selenium (relatively volatile) (source Kehm et aL, 2002).

Figure 11 Average primitive mantle normalized trace-element abundances for alkali basalts. Normalization values from Sun and McDonough (1989) (a) high-titanium alkali basalts, including sodic basalts worldwide and potassic basalts from the western branch of the East African Rift (b) low-titanium potassic alkali basalts and (c) small volume tholeiitic basalts. N-MORB data from Sun and McDonough (1989) (data from sources given in Table 2).

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