Geochemical trends across an arc-continent collision zone: magma sources and slab-wedge transfer processes below the Pantar Strait volcanoes, Indonesia

Late Cretaceous (ca. 90Ma) adakitic intrusive rocks in the Kelu area, Gangdese Belt (southern Tibet): Slab melting and implications for Cu–Au mineralization

“…On a plot of Th/Yb versus Th/Sm (Fig. 5b), the quartz monzonite samples exhibit a linear trend consistent with those of oceanic sediment melts (Elburg et al, 2002;Guo et al, 2007b). In addition, the Sr-Nd isotopic compositions of the Kelu adakitic rocks (Fig.…”

Petrogenesis of the post-collisional Eocene volcanic rocks from the Central Sakarya Zone (Northwestern Anatolia, Turkey): Implications for source characteristics, magma evolution, and tectonic setting

“…In the spider diagrams of the Bozaniç and İğdir lavas, the existence of LILE (K, Rb, and Th) enrichments and depletions related to the Nb, Ti, and Y are the typical indicators of the subduction-related volcanism (e.g., Pearce 1982;Thompson et al 1983;White and Patchett 1984;Wilson 1989;Elburg et al 2002). A large negative Nb anomaly is also a diagnostic feature for an arc environment, and the size of the negative anomaly is immensely important to distinguish between the arc and continental rift rocks (Verma 2009); quantitative values of such anomalies (Nb/Nb*) pm should be very small (0.06-0.30; Verma 2006).…”

Petrology and geochemistry of the Karaj Dam basement sill: Implications for geodynamic evolution of the Alborz magmatic belt

“…These together imply that the samples were not derived from a normal mid-ocean ridge basalt (N-MORB) or an ocean island basalt (OIB) source mantle, which typically display Nb/La 1 (Bradshaw and Smith, 1994;Smith et al, 1999) and positive Nb-Ti anomalies in primitive mantle-normalized trace element diagrams (e.g., Hofmann, 1997). Instead, they are thought to have been derived from a subcontinental lithospheric mantle source that has been enriched in LILEs over HFSEs by the metasomatic activity of fluids derived from the subducted slab or sediments (e.g., Pearce, 1983;Hawkesworth et al, 1997;Elburg et al, 2002;Cameron et al, 2003). On the basis of features of I Sr and Nd (37.2 Ma), it can be inferred that the source of the KDBS rocks is a chemically enriched lithospheric mantle resembling an EM2-type end-member, which is generally interpreted to be the recycled product of terrigeneous sediments from an earlier subduction (Zindler and Hart, 1986;Beccaluva et al, 2004).…”