Ferropigeonite quartz dacites from Chichi-jima, Bonin Islands: Latest differentiates from boninite-forming magma

Geochemical and isotopic study of a plutonic suite and related early volcanic sequences in the southern Mariana forearc

“…The abundance of plagioclase in the RD63 plutonic suite contrasts with the typical characteristics of boninite volcanics, where plagioclase is rarely an abundant mineral except at extreme SiO 2 enrichment (i.e., perlitic dacite and rhyolite from Chichijima) [ Kuroda et al ., ]. Possibly, in the case of the RD63 plutonic rocks, the ascent of boninitic magma was stalled in the midcrust to upper crust, allowing magma degassing and extended low‐pressure crystallization, both of which favor plagioclase stability.…”

A Geochemical Study of Crustal Plutonic Rocks from the Southern Mariana Trench Forearc: Relationship to Volcanic Rocks Erupted during Subduction Initiation

“…The abundance of plagioclase in the RD63 plutonic suite contrasts with the typical characteristics of boninite volcanic rocks, where plagioclase is rarely an abundant mineral except at extreme SiO 2 enrichment (i.e., perlitic dacite and rhyolite from Chichijima, Kuroda, et al, [1988]). Possibly, in the case of the RD63 plutonic rocks, the ascent of boninitic magma was stalled in the mid-to upper crust, allowing magma degassing and extended low-pressure crystallization, both of which favor plagioclase stability.…”

“…RD64 rocks are slightly higher but still low compared with FABs, typical IBM arc lavas and MORBs [Hickey-Vargas, 1989;Ishizuka et al, 2006;Meijer, 1980;Sun and McDonough, 1989;Taylor et al, 1994]. Compared [2010]) and boninite differentiates (blue and yellow square symbols) such as andesites, dacites and rhyolites from Chichijima [Kuroda et al, 1988;Taylor et al, 1994] and bronzite andesites from DSDP Site 458 and 786 [Pearce et al, 1999]. The blue field is boninites from Guam, the southern Mariana forearc and Chichijima ("Bon") [HickeyVargas and Reagan, 1987;Pearce et al, 1999;Reagan et al, 2010;Taylor et al, 1994].…”

“…Potential differentiation pathways for boninite magma can be inferred from differentiated boninite volcanic suites [Hickey-Vargas, 1989;Ishizuka et al, 2006;Kuroda et al, 1988;Kushiro, 1981;Natland and Tarney, 1981;Taylor and Nesbitt, 1995;Taylor et al, 2003;Taylor et al, 1994;Umino, 1985] and observed boninite mineralogy. The abundance of plagioclase in the RD63 plutonic suite contrasts with the typical characteristics of boninite volcanic rocks, where plagioclase is rarely an abundant mineral except at extreme SiO 2 enrichment (i.e., perlitic dacite and rhyolite from Chichijima, Kuroda, et al, [1988]).…”

“…(C) Dacite: lo-Ca pyx [Nagasawa and Schnetzler, 1971], amphibole [Sisson, 1994], apatite [Fujimaki, 1986]. (D) Rhyolite: cpx [Bacon and Druitt, 1988], lo-Ca pyx [Sisson, 1991], amphibole min and max [Sisson, 1994] Reagan et al [2010]) and boninite differentiates (blue and yellow square symbols) such as andesites, dacites and rhyolites from Chichijima [Kuroda et al, 1988;Taylor et al, 1994] and bronzite andesites from DSDP Site 458 and 786 [Pearce et al, 1999]. The blue field is boninites from Guam, the southern Mariana forearc and Chichijima (Bon) [Hickey-Vargas and Reagan, 1987;Pearce et al, 1999;Reagan et al, 2010;Taylor et al, 1994].…”