STABLE ISOTOPES, RARE EARTH ELEMENTS AND PETROGRAPHIC ANALYSIS OF VERTEBRATE FOSSILS FROM SOLIMÕES FORMATION (UPPER MIOCENE, ACRE BASIN, BRAZIL): EXPECTED INSIGHTS ON PALEOECOLOGY, PALEOENVIRONMENT AND TAPHONOMY

2017 ◽  
Author(s):  
Marcos Cesar Bissaro ◽  
◽  
Annie Schmaltz Hsiou ◽  
Renato Pirani Ghilardi ◽  
Jonas Pereira Souza Filho ◽  
...  
Keyword(s):  
Stable Isotopes ◽  
Rare Earth ◽  
Rare Earth Elements ◽  
Petrographic Analysis ◽  
Upper Miocene

scholarly journals Geochemistry and Fuid-Inclusion Microthermometry of the Farsesh Barite Deposit, Iran

Geologos ◽  
2014 ◽  
Vol 20 (3) ◽  
pp. 201-214 ◽  
Author(s):  
Alireza Zarasvandi ◽  
Nazanin Zaheri ◽  
Houshang Pourkaseb ◽  
Abbas Chrachi ◽  
Hashem Bagheri
Keyword(s):  
Rare Earth ◽  
Rare Earth Elements ◽  
Open Space ◽  
Sea Water ◽  
Shear Zones ◽  
Major And Trace Elements ◽  
Petrographic Analysis ◽  
Two Phase ◽  
Moderate Salinity ◽  
Scatter Plots

Abstract The Permian carbonate-hosted Farsesh barite deposit is located southeast of the City of Aligudarz in the province of Lorestan, Iran. Structurally, this deposit lies in the Zagros metallogenic belt and the Sanandaj-Sirjan Zone. Barite mineralisations occur as open-space flling veins, and as massive and replacement ores along fractures, faults and shear zones of the Permian carbonate host rocks. In order to determine the structure, in addition to pe-trographic and fuid-inclusions studies, an ICP-MS analysis was carried out in order to measure the major as well as the trace and rare earth elements. The Farsesh barite deposit has a simple mineralogy, of which barite is the main mineral, followed by calcite, dolomite, quartz, and opaque minerals such as Fe-oxides. Replacement of bar-ite by calcite is common and is more frequent than space-flling mineralisation. Sulphide minerals are minor and mainly consist of chalcopyrite and pyrite, which are altered by weathering to covellite, malachite and azurite. Petrographic analysis and micro-thermometry were carried out on the two-phase liquid/vapour inclusions in ellipsoidal or irregularly shaped minerals ranging in size from 5–10 µm. The measurements were conducted on fuid inclusions during the heating and subsequent homogenisation in the liquid phase. The low homogenisation temperatures (200–125°C) and low to moderate salinity (4.2–20 eq wt% NaCl) indicate that the barite had precipitated from hydrothermal basinal water with low to moderate salinity. It appears from the major and trace elements that geochemical features such as Ba and Sr enrichment in the barite samples was accompanied by depletion of Pb, Zn, Hg, Cu and Sb. The geochemistry of the rare earth elements, such as low σREE concentrations, LREE-enrichment chondrite-normalised REE patterns, the negative Ce and positive Eu anomalies, the low Ce/La ratio and the positive La and Gd anomalies, suggest that the Farsesh barite was deposited from hydrothermally infuenced sea water. The Farsesh deposit contains low-temperature hydrothermal barite. The scatter plots of the barite (close to sea water) in different areas on the CeN/SmN versus CeN/YbN diagram support the possibility that the barite was formed from seawater-bearing hydrothermal fuids.

scholarly journals Provenance Studies of Sandstone Facies Exposed Near Igbile Southwestern Nigeria: Petrographic and Geochemical Approach

2014 ◽  
Vol 6 (2) ◽  
pp. 47 ◽  
Author(s):  
Ikhane P. R. ◽  
Akintola A. I. ◽  
Bankole S. I. ◽  
Oyinboade Y. T.
Keyword(s):  
Rare Earth ◽  
Rare Earth Elements ◽  
Inductively Coupled Plasma ◽  
Tectonic Setting ◽  
Source Area ◽  
Rock Fragment ◽  
Petrographic Analysis ◽  
Humid Climate ◽  
Southwestern Nigeria ◽  
Plagioclase Feldspar

The petrography, as well as the major, trace and rare earth element compositions of ten (10) sandstone samples of Maastrichtian Afowo Formation exposed near Igbile, Southwestern Nigeria, have been investigated to determine their provenance, source area weathering conditions, paleoclimate and tectonic setting using petrographic analysis and Inductively Coupled Plasma - Mass Spectrometry (ICP-MS). Results of the petrographic analysis revealed that quartz is the most dominant detrital mineral with (86%) followed by weathered plagioclase feldspar (5.10%) and rock fragments (10.9%). The quartz grain is sub-angular to sub-rounded in shape and the sandstones were classified as quartz arenites, sublitharenites and subarkoses based on framework composition of quartz, feldspar and rock fragment plots. This suggests a recycled orogen source for the sandstones and deposition in a humid climate, evidenced by the weathered feldspars. Eleven (11) major, seventeen (17) trace and fourteen (14) rare earth elements were obtained from the geochemical analysis. The major elements values range in concentration from 0.01%–81.39% with SiO2 being the dominant oxide followed by Al2O3 and Fe2O3 constituting over 95% of the major oxides; K2O, TiO2, Na2O, CaO, MgO and P2O5 made up the remaining 5%. The average ratio of SiO2/Al2O3 valued 4.31 for the sandstone is appreciably high indicating that it has been heavily weathered. The trace elements range in concentration from 0.2 ppm–1651.2 ppm with Zr being the most dominant element an indication of orogenic recycling. The rare earth elements range in concentration from 0.01 ppm–163.7 ppm with Ce having the highest concentration, depicting that the sandstones were deposited in an oxidizing environment. Also, the trace element relationship illustrated from the spider plot shows chemical coherence and uniformity of the sandstones. The chondrite normalized rare earth elements (REE) plot shows enrichment in the Light REE over the heavy REE for the sediment with strong negative Eu anomaly values between (0.57–0.69) suggesting a felsic provenance derived from upper continental crust for the sandstones.

scholarly journals Proses Pembentukan dan Asal Material Formasi Kayasa di Halmahera Berdasarkan Unsur Jejak dan Unsur Tanah Jarang

EKSPLORIUM ◽  
2019 ◽  
Vol 40 (1) ◽  
pp. 19
Author(s):  
Ronaldo Irzon
Keyword(s):  
Mass Spectrometry ◽  
Rare Earth ◽  
Rare Earth Elements ◽  
Inductively Coupled Plasma ◽  
Petrographic Analysis ◽  
Material Source ◽  
Inductively Coupled ◽  
Rare Elements ◽  
Plasma Mass Spectrometry ◽  
Ree Patterns

ABSTRAKKerumitan pembentukan batuan di Pulau Halmahera dipengaruhi konvergensi setidaknya tiga lempeng besar dan posisinya yang berada dalam kolisi aktif dua busur. Formasi Kayasa adalah salah satu dari empat satuan batuan gunung api di Pulau Halmahera. Analisis petrografi, unsur jarang, dan unsur tanah jarang (UTJ) dimanfaatkan untuk mempelajari proses pembentukan maupun asal materi batuan Formasi Kayasa. Mikroskop bipolar dimanfaatkan pada studi petrografi sedangkan Inductively Coupled Plasma-Mass Spectrometry digunakan untuk analisis kandungan unsur jejak dan unsur tanah jarang terhadap tujuh sampel segar dan empat batuan teralterasi maupun lapuk pada domain Formasi Kayasa. Seluruh sampel segar diklasifikasikan sebagai andesit-basalt berdasarkan perbandingan komposisi kuarsa, K-felspar, dan plagioklas. Kristalisasi fraksional plagioklas diduga berperan penting dalam proses pembentukan Formasi Kayasa. Batuan segar pada studi ini diperkirakan terkristalisasi pada kondisi oksidatif dalam lingkungan laut sedangkan batuan teralterasi atau lapuk terbentuk pada lingkungan reduktif di atas permukaan laut. Berdasarkan pengamatan megaskopis dan pola diagram laba-laba UTJ, material pembentukan Formasi Kayasa sangat mungkin berasal dari lempeng samudera.ABSTRACTThe complexity of rock formation on Halmahera Island is influenced by convergences of at least three main plates and is located in the active collision of two arcs. The Kayasa Formation is one of four volcanic rock units on Halmahera Island. Petrographic analysis, rare elements, and rare earth elements (REE) are applied in studying the rock emplacement process and the material source of Kayasa Formation. Bipolar microscopy is utilized in petrographic studies while Inductively Coupled Plasma-Mass Spectrometry is used for measuring the trace and rare earth elements compositions in seven fresh samples and four altered/weathered rocks in Kayasa Formation’s domain. The fresh samples are classified as andesite-basalt based on quartz, K-feldspar, and plagioclase modal composition. Plagioclase fractional crystallization is thought to play an important role in the crystallization of Kayasa Formations. Fresh rocks in this study tend to crystallize under oxidative conditions in the marine environment, whilst altered or weathered ones formed in a reductive environment above sea level. Based on megascopic observations and REE patterns, the material of Kayasa Formation is very likely derived from the ocean plate.

Sign in / Sign up

Export Citation Format

Share Document