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The SNO+ detector, a new kiloton scale liquid scintillator detector capable of recording geoneutrino events, will define the strength of the Earth radiogenic heat. A detailed 3-D model of the regional crust, centered at SNO+ and based on compiled geological, geophysical and geochemical information, was used to characterize the physical and chemical attributes of crust and assign uncertainties to its structure. Monte Carlo simulations were used to predict the U and Th abundances and uncertainties in crustal lithologies and to model the regional crustal geoneutrino signal originating from the at SNO+.

The recent geoneutrino experimental results from KamLAND and Borexino detectors reveal the usefulness of analyzing the Earth geoneutrino flux, as it provides a constraint on the strength of the radiogenic heat power and this, in turn, provides a test of compositional models of the bulk silicate Earth (BSE). This flux is dependent on the amount and distribution of heat producing elements (HPEs: U, Th and K) in the Earth interior. We have developed a geophysically-based, three-dimensional global reference model for the abundances and distributions of HPEs in the BSE. The structure and composition of the outermost portion of the Earth, the crust and underlying lithospheric mantle, is detailed in the reference model, this portion of the Earth has the greatest influence on the geoneutrino fluxes. The reference model combines three existing geophysical models of the global crust and yields an average crustal thickness of 34.4+-4.1 km in the continents and 8.0+-2.7 km in the oceans. In situ seismic velocity provided by CRUST 2.0 allows us to estimate the average composition of the deep continental crust by using new and updated compositional databases for amphibolite and granulite facies rocks in combination with laboratory ultrasonic velocities measurements. An updated xenolithic peridotite database is used to represent the average composition of continental lithospheric mantle. Monte Carlo simulation is used to predict the geoneutrino flux at 16 selected locations and to track the asymmetrical uncertainties of radiogenic heat power due to the log-normal distributions of HPE concentrations in crustal rocks., Comment: 58 pages, 8 tables, 10 figures

One of the largest uncertainties in crustal composition and growth models is the nature of the lower continental crust. Specifically, by what processes is it formed and modified, and when is it formed, particularly in reference to the upper crust? The main reason for this lack of information is the scarcity of lower crustal rock samples. These are restricted to two types: rocks which outcrop in granulite facies terrains and granulite facies xenoliths which are transported to the earth's surface by young volcanics. The important conclusions arising from the xenolith studies are: the majority of mafic lower crustal xenoliths formed through cumulate process, resitic xenoliths are rare; and formation and metamorphism of the deep crust is intimately linked to igneous activity and/or orogeny which are manifest in one form or another at the earth's surface. Therefore, estimates of crustal growth based on surface exposures is representative, although the proportion of remobilized pre-existing crust may be significantly greater at the surface than in the deep crust.

REE data on metasedimentary rocks from two different types of high-grade Archean terrains are presented and analyzed. The value of REEs as indicators of crustal evolution is explained; the three geologic settings (in North America, Southern Africa, and Australia) from which the samples were obtained are described; and the data are presented in extensive tables and graphs and discussed in terms of metamorphic effects, the role of accessory phases, provenance, and tectonic implications (recycling, the previous extent of high-grade terrains, and a model of Archean crustal growth). The diversity of REE patterns in shallow-shelf metasediments is attributed to local provenance, while the Eu-depleted post-Archean patterns are associated with K-rich plutons from small, stable early Archean terrains.