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Archean rocks may provide a record of early Earth environments. However, such rocks have often been metamorphosed by high pressure and temperature, which can overprint the signatures of their original formation. Here, we show that the early Archean banded rocks from Isua, Akilia, and Innersuartuut, Greenland, are enriched in heavy iron isotopes by 0.1 to 0.5 per mil per atomic mass unit relative to igneous rocks worldwide. The observed enrichments are compatible with the transport, oxidation, and subsequent precipitation of ferrous iron emanating from hydrothermal vents and thus suggest that the original rocks were banded iron formations (BIFs). These variations therefore support a sedimentary origin for the Akilia banded rocks, which represent one of the oldest known occurrences of water-laid deposits on Earth.

Camiguin is a small volcanic island located 12 km north of Mindanao Island in southern Philippines. The island consists of four volcanic centers which have erupted basaltic to rhyolitic calcalkaline lavas during the last ∼400 ka. Major element, trace element and Sr, Nd and Pb isotopic data indicate that the volcanic centers have produced a single lava series from a common mantle source. Modeling results indicate that Camiguin lavas were produced by periodic injection of a parental magma into shallow magma chambers allowing assimilation and fractional crystallization (AFC) processes to take place. The chemical and isotopic composition of Camiguin lavas bears strong resemblance to the majority of lavas from the central Mindanao volcanic field confirming that Camiguin is an extension of the tectonically complex Central Mindanao Arc (CMA). The most likely source of Camiguin and most CMA magmas is the mantle wedge metasomatized by fluids dehydrated from a subducted slab. Some Camiguin high-silica lavas are similar to high-silica lavas from Mindanao, which have been identified as \"adakites\" derived from direct melting of a subducted basaltic crust. More detailed comparison of Camiguin and Mindanao adakites with silicic slab-derived melts and magnesian andesites from the western Aleutians, southernmost Chile and Batan Island in northern Philippines indicates that the Mindanao adakites are not pure slab melts. Rather, the CMA adakites are similar to Camiguin high-silica lavas which are products of an AFC process and have negligible connection to melting of subducted basaltic crust.

Abstract With exception of Maluma (1979) and Musambachime (2016, 2017), there have been no archaeometallurgical publications on the technology and culture of iron production in Zambia. This paper presents archaeological and archaeometallurgical evidence of a technology of iron production in Chongwe in terms of spatial organization, the process of metal production (either a three-stage process involving smelting in relatively tall furnaces, refining in miniature (vintengwe) furnaces, and smithing on a hearth or a two-stage process involving smelting and smithing), furnace air supply mechanisms, liquid slag handling techniques, variation in the geochemistry of ore and clay, and the nature of the final smelting products. Archaeological field data collection techniques included ethnoarchaeological interviews, (furnace) excavation, surface collections, and surface walkover surveys, while laboratory analytical techniques included optical microscopy (OM), scanning electron microscopy (SEM), and x-ray fluorescence (XRF). New field evidence indicates that iron production in Chongwe in the previous two centuries was secluded from respective pre-modern settlements for socio-cultural and technical reasons. There are no settlement remains in and around Chongwe smelting sites. Also, most of the archaeological data in Chongwe are supportive of the two-stage process that did not involve iron refining in vintengwe furnaces. There were no iron refining sites in Chongwe. Archaeological evidence also strongly points to the use of natural air supply mechanism for the smelting furnaces because proximal ends of tuyères inter alia were not trumpeted. All smelting sites were systematically located on termite mounds. There were three to four smelting furnaces located on the western side of a termite mound. The presence of tuyère mould slags and thin and elongated slag microstructures strongly indicates that liquid slag was tapped outside the furnace apparently through tuyères and was left to cool quickly. Presence of primary wüstite and iron particles in the slags strongly suggests the production of iron as the final smelting product in Chongwe. The results are compared with the archaeology, chemistry, and mineralogy of iron production from other parts of sub-Saharan Africa, particularly in the Lake Tanganyika-Nyasa Corridor. The presence of three to four smelting furnaces per termite mound makes iron production in Chongwe a unique technology in the Corridor.

The diamond potential of kimberlites is generally determined using indicator minerals (i.e., xenocrysts), entrained by the parent magma while ascending through the sub-continental lithospheric mantle (SCLM). It is becoming increasingly apparent that olivine can also be used to understand mantle sampling depth, using the Al-in-olivine thermometer, and to constrain the extent of diamond-destructive metasomatism in the SCLM. To further current understanding of vertical sampling and diamond preservation in the SCLM, we present geochemical results for kimberlitic olivine of the Koidu mine (Sierra Leone). We combine our olivine data with pressure-temperature estimates from available olivine diamond inclusions, clinopyroxene xenocrysts, and eclogite xenoliths to visualise the vertical distribution of lithologies in the SCLM beneath Koidu. In agreement with the absence of peridotitic olivine and low abundance of olivine diamond inclusions in the lower SCLM, megacrysts appear to dominate the material sampled from the lowermost lithosphere. At shallower levels a distinct eclogite-dominated region is observed (160-180 km) whereas the SCLM at depths of 110-150 km is heterogeneous comprising depleted harzburgite/dunite, lherzolite, and eclogite. Diamonds are predominantly eclogitic with pressure-temperature estimates for diamondiferous eclogites of 150-190 km within the eclogite-dominated region. The near absence of diamonds sampled from near the lithosphere-asthenosphere boundary is attributed to diamond destruction by extensive infiltration of proto-kimberlite melts leading to metasomatism of the eclogite and peridotite substrate and megacrysts formation. Widespread metasomatism of the deepest reaches of the SCLM sampled by kimberlites elsewhere suggests that Koidu does not represent an isolated case and the extent of diamond-destructive metasomatism can be constrained using olivine xenocrysts.

Collaborative teaming is the glue that holds an inclusive school together. But most educators don't get explicit training on teamwork skills—and that's why you need the new third edition of this popular how-to book. Packed with practical tips, tools, and vignettes, Collaborative Teaming shows your staff how to work together effectively to support students with disabilities in inclusive classrooms. Perfect for independent study, inservice training, or preservice study, this reader-friendly guide will get teachers on board with collaborative teaming and give them fresh ways to improve the academic progress and behavior of all students. LEARN HOW TO: * Master multiple types of teaming, from co-teaching to collaborative consultation * Clearly define a team's purpose and focus * Establish trust and consistent communication among team members * Schedule and facilitate productive team meetings * Make sound decisions by consensus * Solve problems and create action plans as a team * Use teamwork to increase the participation and learning of all students * Ensure positive interactions with families PRACTICAL MATERIALS: Activities that help teachers reflect on and apply the strategies; vignettes that show strategies in action; reproducible forms and checklists for conducting meetings, co-teaching effectively, and more. (For easy printing, full-size forms will now be available for download when you purchase the book.) WHAT'S NEW: * How teaming relates to schoolwide initiatives like PBIS and RTI * Expanded chapter on co-teaching * New chapter on collaborative consultation * More strategies for effective communication and conflict resolution * Insights on using today's technology to collaborate * New vignettes featuring diverse students with a wide range of disabilities * Helpful \"focusing questions\" in each chapter—perfect for use in courses and book clubs