Steven L. Goldstein

TL;DR: In this paper, the average ratio of Sm/Nd is about 0.19 in the upper continental crust, and has remained so since the early Archean, thereby precluding the likelihood of major mafic-to-felsic or felsicto-mafic trends in the overall composition of the sedimentary mass through earth history.

TL;DR: In this paper, a detailed isotope and trace element study of volcanic rocks from Umnak Island, Central Aleutian Arc is presented, where the data require the addition of three distinct subduction components to the subarc mantle, which are characterized and quantified: (1) a hydrous fluid from subducted oceanic crust, with mid-ocean ridge basalt (MORB)-like isotopic compositions but high Pb/Nd, and (2) a sediment partial melt, with sediment-like isotope compositions and high Th/N

TL;DR: In this paper, a mixture of material derived from the mantle at different times is used to estimate the average time that the material in the sample has been resident in the continental crust, which can be interpreted as the time of crust-mantle segregation only if supported by other geologic and geochronological information.

TL;DR: Observations of the Gakkel ridge demonstrate that the extent of mantle melting is not a simple function of spreading rate: mantle temperatures at depth or mantle chemistry (or both) must vary significantly along-axis.

TL;DR: A detailed study of volcanic rocks from the Aleutian island arc shows that this enrichment is a continuing process, and results from the efficient non-magmatic transfer of mantle-derived lead into the source of convergent-margin magmas.