Samarium-neodymium isotopic data on whole rocks and minerals of the Sudbury Complex in Canada gave an igneous crystallization age of 1840 +/- 21 x 10(6) years. The initial epsilon neodymium values for 15 whole rocks are similar to those for average upper continental crust, falling on the crustal trend of neodymium isotopic evolution as defined by shales. The rare earth element concentration pat...

A geophysical transect across the central Gulf of Mexico coastal plain shows that the early Paleozoic continental margin of southern Laurentia is preserved in a nearly pristine state beneath younger strata that were emplaced during the late Paleozoic Ouachita orogeny and formation of the modern Gulf of Mexico coastal plain. The thickness of the crystalline crust decreases abruptly across the ma...

Trace elements (elements that constitute less than 0.1 wt.% of the analyzed sample) are important tracers for a great variety of processes in many research areas, such as biochemistry, medicine, semi-conductor and nano-technology, environmental science and geosciences (e.g., Anitha et al. [2002]; Becker et al. [2004]; Barbante et al. [2004]; Tibi and Heumann [2003]). Accordingly, much scientifi...

A review of continental growth models leaves open the possibilities that Earth during the Hadean Eon (∼4.5–4.0 Ga) was characterized by massive early crust or essentially none at all. Without support from the rock record, our understanding of pre-Archean continental crust must largely come from investigating Hadean detrital zircons. We know that these ancient zircons yield relatively low crysta...

The relationship between the compositions of the Earth and chondritic meteorites is at the center of many important debates. A basic assumption in most models for the Earth's composition is that the refractory elements are present in chondritic proportions relative to each other. This assumption is now challenged by recent (142)Nd/(144)Nd ratio studies suggesting that the bulk silicate Earth (B...

Large igneous provinces (LIPs) are a continuum of voluminous iron and magnesium rich rock emplacements which include continental flood basalts and associated intrusive rocks, volcanic passive margins, oceanic plateaus, submarine ridges, seamount groups, and ocean basin flood basalts. Such provinces do not originate at "normal" seafloor spreading centers. We compile all known in situ LIPs younge...

Rhyolite lavas and xenoliths from the Salton Sea geothermal field (Southern California) provide insights into crustal compositions and processes during continental rupture and incipient formation of oceanic crust. Salton Buttes rhyolite lavas contain xenoliths that include granophyres, fine-grained altered rhyolites (“felsite”), and amphibole-bearing basalts. Zircon is present in lavas and xeno...

Continents ride high above the ocean floor because they are underlain by thick, low-density, Si-rich, and Mg-poor crust. However, the parental magmas of continents were basaltic, which means they must have lost Mg relative to Si during their maturation into continents. Igneous differentiation followed by lower crustal delamination and chemical weathering followed by subduction recycling are pos...

The relationship between the compositions of the Earth and chondritic meteorites is at the center of many important debates. A basic assumption in most models for the Earth’s composition is that the refractory elements are present in chondritic proportions relative to each other. This assumption is now challenged by recent Nd/Nd ratio studies suggesting that the bulk silicate Earth (BSE) might ...

The behavior of the solid Earth system is often overlooked when the causes of major Neoproteozoic (1000–542 Ma) climate and biosphere events are discussed although ∼20% of the present continental crust formed or was remobilized during this time. Processes responsible for forming and deforming the continental crust during Neoproterozoic time were similar to those of the modern Earth and took pla...