Pasir besi atau titanomagnetit ditemukan di wilayah pesisir pantai Indonesia yang tersebar dari Aceh hingga utara Papua. Kandungan logam berharga seperti besi, titanium, dan vanadium belum dimanfaatkan dengan baik karena saat ini ada pabrik pengolahan pemurnian (smelter) dalam negeri mampu mengolah pasir menjadi produk akhir nilai tambah tinggi. Perusahaan hanya konsentrat. Ulasan literatur dis...

Abstract Geochemical and isotopic data are presented for ~ 32 Ma-old high-K andesites dacites from the Alpine Chain. The samples consist of plagioclase, amphibole, titanomagnetite rare biotite quartz. isotope indicate that slab-derived fluids, sediment melts presumably AFC processes involving continental crust played a key role in petrogenesis rocks. A contribution fluids is suggested based on ...

Low-temperature aqueous processes have been implicated in the generation of jarosite and hematite on the martian surface, but little is known regarding the role that high-temperature magmatic fluids may have played in producing similar assemblages on Mars. We have identified jarosite and hematite in a clinopyroxene-hosted melt inclusion in martian meteorite MIL 03346 that shows evidence of havi...

We report paleomagnetic results from four overlapping stratigraphic sections (55 flows) through the lava pile in Tjörnes peninsula (North Iceland). The initial aim of our study was to check the existence of intermediate directions previously interpreted as belonging to the Matuyama-Brunhes geomagnetic reversal (MBR), and complete this record with ThellierThellier paleointensity determinations a...

Introduction: In order to unravel the thermal history of the Martian meteorites Nakhla and Y000593 we applied several geo-thermometers including single and two pyroxene thermometry, the Fe, Ti-thermometer / oxybarometer and TEM microstructures. Application of the Fe,Ti-thermometer/oxyba-rometer: The presence of Fe,Ti-oxide phases enable the application of the Fe,Ti-thermometer /oxybaro-meter [1...

T w o series of pyroxenes have been found in a layered teschenite sill, 22 m thick, emplaced in Late Permian coal measures in the Sydney Basin, New South Wales, Australia. The sill consists of 12 m of homogeneous teschenite, overlain by 6 m of picrite, then by 4 m of a layered sequence. The layering unit of this sequence is teschenite, a pyroxene-rich layer and a narrow leucocratic band. A whol...

Abstract We present a detailed petrologic study of rhyolites from seven eruptions spanning the full (?190 ky) history rhyolitic volcanism at Krafla volcano, northeast Iceland. The vary widely in size and style, but all are crystal-poor (<6 modal%: plagioclase + augite ± pigeonite orthopyroxene titanomagnetite fayalite) have similar evolved compositions (73.7–75.8 wt% normalized whole-roc...

Abstract The Bishop Tuff (BT), erupted from the Long Valley caldera in California, displays two types of geochemical gradients with temperature: one is related to magma mixing, whereas other found high-SiO2 rhyolite portion and characterized by twofold or lower concentration variations minor trace elements that are strongly correlated temperature. It proposed latter zonation, which preceded phe...

Abstract Eastern Australia encompasses the longest track (~2000 km) of age-progressive continental volcanoes on Earth. These so-called ‘central volcanoes’ are shield considered as surficial expressions Cenozoic mantle plume activity under northward moving Australian continent. Here, we investigate three central located in southern, younger part volcanic (Ebor, Nandewar, and Canobolas) with aim ...