To first order, the Earth as well as other rocky planets in the Solar System and rocky exoplanets orbiting other stars, are refractory pieces of the stellar nebula out of which they formed. To estimate the chemical composition of rocky exoplanets based on their stellar hosts' elemental abundances, we need a better understanding of the devolatilization that produced the Earth. To quantify the chemical relationships between the Earth, the Sun and other bodies in the Solar System, the elemental abundances of the bulk Earth are required. The key to comparing Earth's composition with those of other objects is to have a determination of the bulk composition with an appropriate estimate of uncertainties. Here we present concordance estimates (with uncertainties) of the elemental abundances of the bulk Earth, which can be used in such studies. First we compile, combine and renormalize a large set of heterogeneous literature values of the primitive mantle (PM) and of the core. We then integrate standard radial density profiles of the Earth and renormalize them to the current best estimate for the mass of the Earth. Using estimates of the uncertainties in i) the density profiles, ii) the core-mantle boundary and iii) the inner core boundary, we employ standard error propagation to obtain a core mass fraction of 32.5 ± 0.3 wt%. Our bulk Earth abundances are the weighted sum of our concordance core abundances and concordance PM abundances. Unlike previous efforts, the uncertainty on the core mass fraction is propagated to the uncertainties on the bulk Earth elemental abundances. Our concordance estimates for the abundances of Mg, Sn, Br, B, Cd and Be are significantly lower than previous estimates of the bulk Earth. Our concordance estimates for the abundances of Na, K, Cl, Zn, Sr, F, Ga, Rb, Nb, Gd, Ta, He, Ar, and Kr are significantly higher. The uncertainties on our elemental abundances usefully calibrate the unresolved discrepancies between standard Earth models under various geochemical and geophysical assumptions.

Exoplanet interior modelling usually makes the assumption that the elemental abundances of a planet are identical to those of its host star. Host stellar abundances are good proxies of planetary abundances, but only for refractory elements. This is particularly true for terrestrial planets, as evidenced by the relative differences in bulk chemical composition between the Sun and the Earth and other inner solar system bodies. The elemental abundances of a planet host star must therefore be devolatilised in order to correctly represent the bulk chemical composition of its terrestrial planets. Furthermore, nickel and light elements make an important contribution alongside iron to the core of terrestrial planets. We therefore adopt an extended chemical network of the core, constrained by an Fe/Ni ratio of 18 ± 4 (by number). By applying these constraints to the Sun, our modelling reproduces the composition of the mantle and core, as well as the core mass fraction of the Earth. We also apply our modelling to four exoplanet host stars with precisely measured elemental abundances: Kepler-10, Kepler-20, Kepler-21 and Kepler-100. If these stars would also host terrestrial planets in their habitable zone, we find that such planets orbiting Kepler-21 would be the most Earth-like, while those orbiting Kepler-10 would be the least. To assess the similarity of a rocky exoplanet to the Earth in terms of interior composition and structure, highprecision host stellar abundances are critical. Our modelling implies that abundance uncertainties should be better than ∼ 0.04 dex for such an assessment to be made.

We present new estimates of protosolar elemental abundances based on an improved combination of solar photospheric abundances and CI chondritic abundances. These new estimates indicate CI chondrites and solar abundances are consistent for 60 elements. Our estimate of the protosolar "metallicity" (i.e. mass fraction of metals, Z) is 1.40%, which is consistent with a value of Z that has been decreasing steadily over the past three decades from ∼ 1.9%. We compare our new protosolar abundances with our recent estimates of bulk Earth composition (normalized to aluminium), thereby quantifying the devolatilization in going from the solar nebula to the formation of the Earth. The quantification yields a linear trend log( f ) = α log(T C ) + β, where f is the Earth-to-Sun abundance ratio and T C is the 50% condensation temperature of elements. The best fit coefficients are: α = 3.676 ± 0.142 and β = −11.556 ± 0.436. The quantification of these parameters constrains models of devolatilization processes. For example, the coefficients α and β determine a critical devolatilization temperature for the Earth T D (E) = 1391 ± 15 K. The terrestrial abundances of elements with T C < T D (E) are depleted compared with solar abundances, whereas the terrestrial abundances of elements with T C > T D (E) are indistinguishable from solar abundances. The abundances of noble gases and hydrogen are depleted more than a prediction based on the extrapolation of the best-fit volatility trend. The terrestrial abundance of Hg (T C = 252 K) appears anomalously high under the assumption that solar and CI chondrite Hg abundances are identical. To resolve this anomaly, we propose that CI chondrites have been depleted in Hg relative to the Sun by a factor of 13 ± 7. We use the best-fit volatility trend to derive the fractional distribution of carbon and oxygen between volatile and refractory components ( f vol , f ref ). For carbon we find (0.91 ± 0.08, 0.09 ± 0.08); for oxygen we find (0.80 ± 0.04, 0.20 ± 0.04). Our preliminary estimate gives CI chondrites a critical devolatilization temperature T D (CI) = 550 +20 −100 K.

We present a line-by-line differential analysis of a sample of 16 planet-hosting stars and 68 comparison stars using high-resolution, high signal-to-noise ratio spectra gathered using Keck. We obtained accurate stellar parameters and high-precision relative chemical abundances with average uncertainties in Teff, log g, [Fe/H], and [X/H] of 15 K, 0.034 cm s−2 , 0.012 dex, and 0.025 dex, respectively. For each planet host, we identify a set of comparison stars and examine the abundance differences (corrected for Galactic chemical evolution effect) as a function of the dust condensation temperature, Tcond, of the individual elements. While we confirm that the Sun exhibits a negative trend between abundance and Tcond, we also confirm that the remaining planet hosts exhibit a variety of abundance–Tcond trends with no clear dependence upon age, metallicity, or Teff. The diversity in the chemical compositions of planet-hosting stars relative to their comparison stars could reflect the range of possible planet-induced effects present in these planet hosts, from the sequestration of rocky material (refractory poor) to the possible ingestion of planets (refractory rich). Other possible explanations include differences in the time-scale, efficiency and degree of planet formation, or inhomogeneous chemical evolution. Although we do not find an unambiguous chemical signature of planet formation among our sample, the high-precision chemical abundances of the host stars are essential for constraining the composition and structure of their exoplanets.

The major storage space types in the carbonate reservoir in the Ordovician in the TZ45 area are secondary dissolution caves. For the prediction of caved carbonate reservoir, post-stack methods are commonly used in the oilfi eld at present since pre-stack inversion is always limited by poor seismic data quality and insuffi cient logging data. In this paper, based on amplitude preserved seismic data processing and rock-physics analysis, pre-stack inversion is employed to predict the caved carbonate reservoir in TZ45 area by seriously controlling the quality of inversion procedures. These procedures mainly include angle-gather conversion, partial stack, wavelet estimation, low-frequency model building and inversion residual analysis. The amplitude-preserved data processing method can achieve high quality data based on the principle that they are very consistent with the synthetics. Besides, the foundation of pre-stack inversion and reservoir prediction criterion can be established by the connection between reservoir property and seismic refl ection through rock-physics analysis. Finally, the inversion result is consistent with drilling wells in most cases. It is concluded that integrated with amplitude-preserved processing and rock-physics, pre-stack inversion can be effectively applied in the caved carbonate reservoir prediction.