Plan uchastka kolfonda litera "I" Mikhaĭlovskogo raĭona Krivorogskogo okruga ploshchadiʻ︠u︡ 458 desi︠a︡tin

Digital image

HG 458.25-458.35

Dark brown sediment, with clasts ranging from small to large. The sample mainly contained smaller clasts. The clast shape ranges from sub-angular to sub-rounded. Lineations were common throughout the sample. It also contained areas with dark organic material, and a few faint water escape structures.

Ms.Ff.F.Stoltze 3. 458 - Brief von Friedrich Stoltze an Lyda Stoltze

Lindenfels, Felsberg, Frankfurter Latern, Johann Georg Zehfuß, Marie Geisselbrecht

Element abundances and Nd isotopic composition in boninite and tholeiite from DSDP Hole 60-458

Boninites are unusual high MgO-high SiO2 volcanic rocks found in several western Pacific island arcs. Their high Mg/(Mg + total Fe) (0.55-0.83) and compatible element contents (Ni = 70-450 ppm, Cr = 200-1800 ppm) indicate equilibration with mantle peridotite, but their low TiO2 contents (0.1-0.5%) indicate severe depletion of this source. K, Rb, Sr and Ba abundances in boninites are typical of primitive arc basalts, but ratios such as Ti/Zr and La/Yb are variable (Ti/Zr = 23-67, (La/Yb)e.f. = 0.6-4.7). Evidence for both enrichment and depletion of incompatible elements suggests that boninites are derived from refractory peridotite which has been metasomatically enriched in LREE, Zr, Sr, Ba and alkalis. Wide variations in 143Nd/144Nd (0.51262-0.51296) are correlated with La/Sm, Sm/Nd and Ti/Zr, which enables identification of components in the boninite source. Possible LREE depleted components have relative REE and Ti abundances like those in depleted peridotites and high 143Nd/144Nd ratios which reach MORB-like values. Possible LREE enriched components have relative REE abundances similar to those in metasomatized mantle peridotite nodules, and low 143Nd/144Nd ratios which indicate either sedimentary sources or mantle sources with recent to ancient LREE enrichment. Relative abundances of Ba and Sr in boninites decrease with increasing LREE enrichment and suggest a non-sedimentary source for the LREE enriched material. Enrichment in Ba, Sr and alkalis may result from a third component derived from subducted oceanic crust. Two models can account for the successive generation of boninites and arc tholeiites within a single area: 1) boninites can be derived from the peridotite residue of earlier arc tholeiite generation which is metasomatically enriched in LREE before boninite volcanism, or 2) arc tholeiites and boninites can be derived from a variably depleted peridotite source which has been pervasively enriched in LREE. Areas of fertile peridotite would yield tholeiites while refractory areas would yield boninites.

Origène, commentaire sur l´épitre aux Romains, tome 1 (Livres I-II). Texte critique établi par C.P. Hammond Bammel. Introduction par Michel Fédou, s.j.. Traduction, notes et index par Luc Brésard, o.c.s.o. (Sources Chrétiennes 532), Cerf, Paris, 2009; 458 pp. ISBN 978-2- 204-09164-0.

Fil: Peretó Rivas, Rubén.