Halogen-bearing metasomatizing melt preserved in high-pressure (HP) eclogites of Pfaffenberg, Bohemian Massif

Primary granitic melt inclusions are trapped in garnets of eclogites in the garnet peridotite body of Pfaffenberg, Granulitgebirge (Bohemian Massif, Germany). These polycrystalline inclusions, based on their nature and composition, can be called nanogranitoids and contain mainly phlogopite/biotite, kumdykolite, quartz/rare cristobalite, a phase with the main Raman peak at 412 cm−1, a phase with the main Raman peak at 430 cm−1, osumilite and plagioclase. The melt is hydrous, peraluminous and granitic and significantly enriched in large ion lithophile elements (LILE), Th, U, Li, B and Pb. The melt major element composition resembles that of melts produced by the partial melting of metasediments, as also supported by its trace element signature characterized by elements (LILE, Pb, Li and B) typical of the continental crust. These microstructural and geochemical features suggest that the investigated melt originated in the subducted continental crust and interacted with the mantle to produce the Pfaffenberg eclogite. Moreover, in situ analyses and calculations based on partition coefficients between apatite and melt show that the melt was also enriched in Cl and F, pointing toward the presence of a brine during melting. The melt preserved in inclusions can thus be regarded as an example of a metasomatizing agent present at depth and responsible for the interaction between the crust and the mantle. Chemical similarities between this melt and other metasomatizing melts measured in other eclogites from the Granulitgebirge and Erzgebirge, in addition to the overall similar enrichment in trace elements observed in other metasomatized mantle rocks from central Europe, suggest an extended crustal contamination of the mantle beneath the Bohemian Massif during the Variscan orogeny.</p

CHEMICAL TECHNOLOGY DIVISION, CHEMICAL DEVELOPMENT SECTION C PROGRESS REPORT FOR DECEMBER 1959 AND JANUARY 1960

The recovery of Th from Blind River ion exchange barrens with di(2- ethylhexyl)phosphoric acid was investigated. The recovery of Tc and Np from fluorination plant residues with tertiary amine was studied. The extraction of Np/sup 4+/ by quaternary ammonium nitrates is reported. A solvent recovery procedure involving successive use of Na/sub 2/CO/sub 3/washing and Al/sub 2/O/ sub 3/- adsorption was demonstrated in laboratory tests as a possible method for the purification and decontamaination of organophosphorus process solvents. The effect of nitrated fractions of Annsco 125-82 on Zr-Nb extractions by TBP was investigated. Treatnnent of TBPAmsco 125-82 solutions with 2 M HNO/sub 3/ at 60 ction prod- C for 1 to 48 hr showed that under these mild conditions the TBP degradation products were more important than those from Amsco as contributors to Zr-Nb extraction and as affecting efficiency of solvent clean-up. The interfacial tensions between benzene solutions of several amine salt and alkyl phosphate extractants and aqueous solutions were examined as functions of the solute concentrations. (For preceding period see CF-59-11-132.) (W.L.H.

Language continuity despite population replacement in Remote Oceania

Recent genomic analyses show that the earliest peoples reaching Remote Oceania—associated with Austronesian-speaking Lapita culture—were almost completely East Asian, without detectable Papuan ancestry. However, Papuan-related genetic ancestry is found across present-day Pacific populations, indicating that peoples from Near Oceania have played a significant, but largely unknown, ancestral role. Here, new genome-wide data from 19 ancient South Pacific individuals provide direct evidence of a so-far undescribed Papuan expansion into Remote Oceania starting ~2,500 yr BP, far earlier than previously estimated and supporting a model from historical linguistics. New genome-wide data from 27 contemporary ni-Vanuatu demonstrate a subsequent and almost complete replacement of Lapita-Austronesian by Near Oceanian ancestry. Despite this massive demographic change, incoming Papuan languages did not replace Austronesian languages. Population replacement with language continuity is extremely rare—if not unprecedented—in human history. Our analyses show that rather than one large-scale event, the process was incremental and complex, with repeated migrations and sex-biased admixture with peoples from the Bismarck Archipelago

Halogen-bearing metasomatizing melt preserved in high-pressure (HP) eclogites of Pfaffenberg, Bohemian Massif

Primary granitic melt inclusions are trapped in garnets of eclogites in the garnet peridotite body of Pfaffenberg, Granulitgebirge (Bohemian Massif, Germany). These polycrystalline inclusions, based on their nature and composition, can be called nanogranitoids and contain mainly phlogopite/biotite, kumdykolite, quartz/rare cristobalite, a phase with the main Raman peak at 412cm-1, a phase with the main Raman peak at 430cm-1, osumilite and plagioclase. The melt is hydrous, peraluminous and granitic and significantly enriched in large ion lithophile elements (LILE), Th, U, Li, B and Pb. The melt major element composition resembles that of melts produced by the partial melting of metasediments, as also supported by its trace element signature characterized by elements (LILE, Pb, Li and B) typical of the continental crust. These microstructural and geochemical features suggest that the investigated melt originated in the subducted continental crust and interacted with the mantle to produce the Pfaffenberg eclogite. Moreover, in situ analyses and calculations based on partition coefficients between apatite and melt show that the melt was also enriched in Cl and F, pointing toward the presence of a brine during melting. The melt preserved in inclusions can thus be regarded as an example of a metasomatizing agent present at depth and responsible for the interaction between the crust and the mantle. Chemical similarities between this melt and other metasomatizing melts measured in other eclogites from the Granulitgebirge and Erzgebirge, in addition to the overall similar enrichment in trace elements observed in other metasomatized mantle rocks from central Europe, suggest an extended crustal contamination of the mantle beneath the Bohemian Massif during the Variscan orogeny.ISSN:0935-1221ISSN:1617-401

COMPARISON OF DIALKYL PHENYLPHOSPHONATES WITH TRI-n-BUTYL PHOSPHATE IN NITRATE SYSTEMS: EXTRACTION PROPERTIES, STABILITY, AND EFFECT OF DILUENT ON THE RECOVERY OF URANIUM AND THORIUM FROM SPENT FUELS

Di-n-butyl phenylphosphonate (DBPP) and di-sec-butyl phenylphosphonate (DSBPP) were investigated as possible substitutes for tri-n-butyl phosphate (TBP), the reagent presently employed in the reprocessing of uranium and thorium nuclear reactor fuels. The phenylphosphonates form complexes with uranium and thorium that are mostly insoluble in the aliphatic solvents commonly used as diluerts for TBP but that are soluble in other diluert type, for example, aromatics and CCl/sub 4/. Therefore, the phosphonates were diluted with aromatics and the TBP was diluted with both aliphatic and aromatic diluents. DSBPParomatic solutions showed advantages over TBP-aromatic solutions during batch contact with nitric acid systems in the following respects: higher uranium extractability (1.2 to 1.8 times higher); better stability to radiation and chemical degradation (1.3 times better); higher separation of uranium from thorium (U/Th, 10 times higher) and from flssion products (U/gross BETA , about 2.4 times higher; U/ gross gamma , about 1.4 times higher). Plutonium extractiong with DSBPP and with TBP were nearly identical. The TBP-aromatic solvent combination also showed advantages over the TBP-aliphatic solvert combination in regard to radiation stability (2.4 times better), uranium extractability (1.5 times better), plutonium(IV) extractabtlity (twice as good), U/gross gamma separation (3.1 times higher) and U/ gross BETA separation (2.4 times higher). The comparison of the DSBPP-- aromatic solvent combination with TBP in the usual aliphatic diluent was consequently much more favorable to DSBPP than comparison with the TBParomatic. DBPP-aromatic solutions extracted uranium, thorium, plutonium, and fission products better than did TBP in either diluert system, The uranium--thorium separability was between those of the two TBP systems, and the urarium-gross BETA - gamma separability was about the same as for the TBP-aromatic but better than the TBPaliphatic combination. Under irradiation the DBPParomatic was slightiy more stable than the TBP-aliphatic, but not as stable as the TBP-aromatic. Countercurrert batch testing with simulated Purex feeds verified the single-batch contact data pertaining to uranium extractions with each reagent system and also verified the differences between TBP-aliphatic and TBP-aromatic systems. The higher uranium extractability ahown by DSBPP and by BBPP in comparison with TBP suggests their use to permit lower aqueous nitric acid or nitrate salting concertrations in a urarium recovery operation, for example, to effect reduction in chemical costs and/or to alleviate problems in nitric acid evaporation and recovery from high-level radioactive waste solutions. Since use of aromatic instead of aliphatic diluents with TBP improves its uranium extractability and fission product separabtlity, such dtluents can be considered where the performance of the TBP-aliphatic combination is marginal. (auth