Rocks elemental abundances

Taken from W. S. Fyfe, Geochemistry, Oxford University Press, 1974, with some modifications and additions to incorporate later data. The detailed numbers are subject to various assumptions in the models of the global distribution of the various rock types within the crust, but they are broadly acceptable as an indication of elemental abundances. See also Table 1 in C. K. J0RGENSEN, Comments Astrophys. 17, 49-101 (1993). 

At the same time, the abundance ratios among the elements heavier than Al, at least through the Fe peak, do not show any detectable variation in any known GC (except, of course, iv Cen). The rock steady abundances for these elements requires explanation as well, and places important constraints on the formation mechanisms of GCs. 

The historical background is presented for the asteroid-impact theory that is based on the iridium anomaly found in rocks frm the Cretaceous-Tertiary boundary. Recent measurements of Ir, Pt, and Au abundances from such rocks in Denmark have shown that the element abundance ratios are different from mantle-derived sources and agree with values for chondritic meteorites within one standard deviation of the measurement errors (7-10%). Rare-earth patterns for these rocks are... 

KEYWORDS Elemental abundance, rocks, sediments, continental crust, China... 

Elemental abundances in various types of geological media such as rocks, sediments and soils of China have been studied since 1980s. These data were published in many literatures (Chi Yan 2007 Yan Chi 1997, 2005 Ren et al. 1998 Zhao Yan 1994 Zhu et al. 2006). To provide readers with a general overview and convenient use, the authors collected these published data and compiled a concise data set in this paper. 

Table 1. Elemental abundances of rocks, soils, sediments, and the continental crust in China...

The number of composite samples for analysis is indicated as N and the number of collected individual rock samples is indicated as n . The number of data without brackets is for major elements, while that with brackets is for trace elements and those without brackets for the both mean that they are the same. The data of element abundance with brackets in the table are for reference. 

Trace elements and rare-earth elements (REEs) of the same calcite samples used for the stable isotope analysis have significantly lower concentration of REE as well as most trace elements relative to typical carbonatites. The total REE contents of the Ulsan carbonates range from 3 to 17 ppm, which are much lower than any igneous rocks and even lower than those of some sedimentary rocks. REE and trace-element abundances may have changed sufficiently due to alteration, thus, affecting petrogenetic... 

Frey F. A. (1982). Rare earth element abundances in upper mantle rocks. In Rare Earth Element Geochemistry, R Henderson, ed. Elesevier, Amsterdam. 

The distributions of trace elements between minerals and within a suite of related rocks provide powerful tools for constraining the origin and history of rocks and meteorites. Trace-element abundances for rocks typically are part of the data set collected when determining bulk compositions. Trace element compositions of minerals require more powerful techniques such as the ion microprobe or the laser-ablation inductively coupled plasma mass spectrometer (ICPMS). 

In most respects, asteroid 4 Vesta is geochemically similar to the Moon. As judged from howardite-eucrite-diogenite (HED) meteorites (see Chapter 6), Vesta is an ancient, basalt-covered world (Keil, 2002). Its rocks are highly reduced, and its depletions in volatile and siderophile element abundances resemble those of lunar basalts. And like the Moon, Vesta is hypothesized to have had an early magma ocean. The exploration of Vesta is now in progress, and within a few years we may have enough data to discuss it in a similar way that we have considered the Moon. 

The Mars Pathfinder rover carried an Alpha Proton X-ray Spectrometer (APXS), and the two Mars Exploration Rovers (MER - Spirit and Opportunity) carried Alpha Particle X-ray Spectrometers (also called APXS, but in this case more precise versions of the Pathfinder instrument, though without the ability to monitor protons for light element analyses). These instruments contained radioactive curium sources (Fig. 13.16) whose decay produced a-particles, which irradiated target rocks and soils. The resulting characteristic X-rays provided measurements of major and minor element abundances. The MER rovers also carried Mossbauer spectrometers, which yielded information on iron oxidation state. 

The applications of activation analysis are almost innumerable. In the physical sciences, activation analysis is used in trace-element analysis of semiconductor materials, metals, meteorites, lunar samples, and terrestrial rocks. In most cases, the multielemental analysis feature of activation analysis is used to measure the concentrations of several trace-elements simultaneously. From these detailed studies of trace-element abundance patterns, one has been able to deduce information about the thermal and chemical history of the Earth, moon, Mars, and meteorites, as well as the source or age of an object. 

Mafic Plio-Quatemary rocks in Italy show very variable trace element and isotopic compositions. Incompatible2 trace element abundances and ratios are best illustrated by mantle-normalised diagrams (spiderdiagrams), where concentrations of single elements in the rocks are divided by the abundances of the same elements in the mantle (Wood 1979). 

The mafic rocks in Tuscany have highly variable compositions in terms of major elements, incompatible element abundances and isotopic signatures. 

The mafic nature of all the Monti Ernici rocks, and the large differences in incompatible element abundances and isotopic signatures between rock... 

The Emici and Roccamonfina magmas exhibit peculiar compositional characteristics in terms of their very variable geochemical and isotopic signatures for potassic to ultrapotassic mafic rocks. These are not encountered in other potassic volcanoes of central Italy (i.e. Roman and Campanian provinces, with the possible exception of Vico volcano), where coexisting KS and HKS rocks have different potassium and incompatible trace element abundances but exhibit similar incompatible element ratios and radiogenic isotope signatures (Peccerillo 1999, 2002). 

REE patterns are fractionated silicic rocks contain negative Eu anomalies (Fig. 7.14a), which are much smaller than observed for the Lipari and Vulcano rhyolites. Mantle normalised incompatible element patterns of mafic rocks show high LILE/HFSE ratios and a positive anomaly of Pb a small positive Sr spike is observed in the calc-alkaline basaltic andesites (Fig. 7.14b). HKCA and shoshonitic rocks have higher incompatible element abundances than the associated CA products. 

Trace element abundances of rocks dredged from the Sicily Channel seamounts are scarce (Beccaluva et al. 1981 Calanchi et al. 1989). They show variable concentrations, with incompatible element abundances increasing from tholeiitic to alkaline basalts and basanites (Fig. 8.17). Mantle normalised incompatible elements define bell-shaped patterns (not shown), which resemble those for the exposed rocks in the Sicily Channel. 

We summarize noble gas amounts in deep-sea and subaerial sediments in Figure 5.1. From the data displayed here, we calculated median values which are shown in Table 5.1. Both Figure 5.1 and Table 5.1 show that even though there is little difference in the lighter noble gas concentration between subaerial and deep-sea sediments (He, Ne, and Ar), heavier noble gases are much more abundant in subaerial sediments than in deep-sea sediments. As in volcanic rocks (cf. Section 6.6), most sediments, either deep-sea or subaerial, show fractionation toward the heavier ones relative to air noble gas, although the mechanism for the fractionation may be different. Figure 5.2 shows noble a gas elemental abundance pattern relative to the air abundance subaerial sediments show much more severe fractionation. 

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