REE Minerals as Geochemical Proxies of Late-Tertiary Alkalic Silicate ± Carbonatite Intrusions Beneath Carpathian Back-Arc Basin

The accessory mineral assemblage (AMA) of igneous cumulate xenoliths in volcanoclastic deposits and lava flows in the Carpathian back-arc basin testifies to the composition of intrusive complexes sampled by Upper Miocene-Pliocene basalt volcanoes. The magmatic reservoir beneath Pinciná maar is composed of gabbro, moderately alkalic to alkali-calcic syenite, and calcic orthopyroxene granite (pincinite). The intrusive complex beneath the wider area around Fiľakovo and Hajnáčka maars contains mafic cumulates, alkalic syenite, carbonatite, and calc-alkalic granite. Both reservoirs originated during the basaltic magma underplating, differentiation, and interaction with the surrounding mantle and crust. The AMA of syenites is characterized by yttrialite-Y, britholite-Y, britholite-Ce, chevkinite-Ce, monazite-Ce, and rhabdophane(?). Baddeleyite and REE-zirconolite are typical of alkalic syenite associated with carbonatite. Pyrochlore, columbite-Mn, and Ca-niobates occur in calc-alkalic granites with strong peralkalic affinity. Nb-rutile, niobian ilmenite, and fergusonite-Y are crystallized from mildly alkalic syenite and calc-alkalic granite. Zircons with increased Hf/Zr and Th/U ratios occur in all felsic-to-intermediate rock-types. If rock fragments are absent in the volcanic ejecta, the composition of the sub-volcanic reservoir can be reconstructed from the specific AMA and zircon xenocrysts–xenolith relics disintegrated during the basaltic magma fragmentation and explosion.

Synneusis: does its preservation imply magma mixing?

The Ghansura Felsic Dome (GFD) occurring in the Bathani volcano-sedimentary sequence was intruded by mafic magma during its evolution leading to magma mixing. In addition to the mafic and felsic rocks, a porphyritic intermediate rock occurs in the GFD. The study of this rock may significantly contribute toward understanding the magmatic evolution of the Ghansura dome. The porphyritic rock preserves several textures indicating its hybrid nature, i.e. that it is a product of mafic-felsic magma mixing. Here, we aim to explain the origin of the intermediate rock with the help of textural features and mineral compositions. Monomineralic aggregates or glomerocrysts of plagioclase give the rock its characteristic porphyritic appearance. The fact that the plagioclase crystals constituting the glomerocrysts are joined along prominent euhedral crystal faces suggests the role of synneusis in the formation of the glomerocrysts. The compositions of the glomerocryst plagioclases are similar to those of plagioclases in the mafic rocks. The results from this study indicate that the porphyritic intermediate rock formed by the mixing of a crystal-rich mafic magma and a crystal-poor felsic melt.

Kelangsungan Hidup Bayi di Perkotaan dan Pedesaan Indonesia

Kelangsungan hidup bayi di Indonesia yang masih rendah terlihat pada angka kematian bayi (AKB) yang menempati posisi tertinggi di Asean, kondisi intermediate rock dan sangat bervariasi. Penelitian yang menggunakan sumber data sekunder SDKI 2002-2003 ini bertujuan mengetahui gambaran kelangsungan hidup bayi di wilayah perkotaan dan pedesaan di Indonesia serta berbagai faktor yang berpengaruh. Besar sampel yang digunakan adalah 11.588 terdiri dari 4.769 bayi di perko- taan dan 6.819 bayi di pedesaan. Metoda analisis yang digunakan meliputi metode life table dan regresi cox. Hasil penelitian memperlihatkan probabilitas kelangsungan hidup bayi di perkotaan (98,59%) lebih tinggi daripada bayi di pedesaan (97,54%) dan proporsi kematian bayi di pedesaan dua kali lebih besar daripada di perkotaan. Pada masa neonatal, kurva kelangsungan hidup bayi memperlihatkan kecenderungan yang menurun tajam dan post neonatal terlihat lebih landai. Penurunan probabilitas kelangsungan hidup bayi di wilayah perkotaan terlihat lebih landai daripada di wilayah pedesaan. Terdapat perbedaan faktor-faktor yang berhubungan dengan kelangsungan hidup bayi di perkotaan dan pedesaan. Di perkotaan, faktor-faktor yang berhubungan dengan kelangsungan hidup bayi meliputi berat badan lahir, waktu pemberian ASI dan penolong persalinan. Sedangkan di pedesaan, faktor tersebut adalah frekuensi pemeriksaan antenatal, berat badan lahir, penolong persalinan, nomor urut lahir, waktu pemberian ASI dan tempat persalinan. Keadaan saat lahir merupakan faktor penting yang berhubungan signifikan dengan kelangsungan hidup bayi, faktor waktu pemberian ASI pertama kali merupakan faktor dominan yang berhubungan dengan kelangsungan hidup bayi.Kata kunci : Kelangsungan hidup bayi, perkotaan dan pedesaan, analisis kesintasan.AbstractInfant’s survival in Indonesia is still low, as showed by the highest IMR level in ASEAN, intermediate rock condition and highly varied. This research’s aim is to des- cribe infant’s survival in Indonesia’s urban and rural area, also various factors related. This research is using SDKI 2002-2003 data. Sample’s amount 11.588 infant, consist of 4.769 infant in urban and 6.819 infant in rural. Method of analysis used in this study is life table and cox regression. This research found probability infant’s survival in urban (98, 59%) higher than in rural (97, 54%) and infant’s mortality proportion in rural is twice higher than in urban. On first month age (neonatal mortali- ty) infant’s survival time probability was decline, and for higher age infant’s survival time probability is still low, but not as low as the first month age. In urban area, infant’s survival time probability is even lower than in rural. There are determinant factors which are related to infant’s survival in rural and urban. In urban, factors which are related to infant’s survival are birth weight, breast feeding period and birth assistance. Meanwhile in rural area, the factors of are antenatal care, birth weight, birth assistance, birth queue number, breast feeding period and bearing place. Infant condition when the baby born is determinant factors which is related significantly with infant’s survival, first breast feeding period is dominant factor which is related with infant’s survival.Key words : Infant survival, rural and urban, survival analysis

Evidence of mingling between contrasting magmas in a deep plutonic environment: the example of Várzea Alegre, in the Ribeira Mobile Belt, Espírito Santo, Brazil

At the end of the geotectonic cycle that shaped the northern segment of the Ribeira Mobile Belt (Upper Proterozoic to Paleozoic age), a late to post-collisional set of plutonic complexes, consisting of a wide range of lithotypes, intruded all metamorphic units. The Várzea Alegre Intrusive Complex is a post-collisional complex. The younger intrusion consists of an inversely zoned multistage structure envolved by a large early emplaced ring of megaporphyritic charnoenderbitic rocks. The combination of field, petrographic and geochemical data reveals the presence of at least two different series of igneous rocks. The first originated from the partial melting of the mantle. This was previously enriched in incompatible elements, low and intermediate REE and some HFS-elements. A second enrichment in LREE and incompatible elements in this series was due to the mingling with a crustal granitic magma. This mingling process changed the composition of the original tholeiitic magma towards a medium-K calc-alkalic magma to produce a suite of basic to intermediate rock types. The granitic magma from the second high-K, calc-alkalic suite originated from the partial melting of the continental crust, but with strong influence of mantle-derived melts.