scholarly journals ALTERACE DETRITICKÉHO TITANITU V KULMU DRAHANSKÉ VRCHOVINY

2016 ◽  
Vol 22 (1-2) ◽  
Author(s):  
Aleš Novotný ◽  
Renata Čopjaková
Keyword(s):  
Sedimentary Rocks ◽  
Accessory Mineral ◽  
Authigenic Minerals ◽  
Magmatic Rocks ◽  
Deep Burial ◽  
Clastic Sediments ◽  
Diagenetic Fluids ◽  
Maximum Temperatures ◽  
Diagenetic Fluid ◽  
Detrital Mineral

Titanite is a common accessory mineral of magmatic rocks, low- and medium-grade metamorphic rocks and it occurs as a detrital mineral in clastic sediments. Our paper deals with titanite alterations as a result of interaction of diagenetic fluids with detrital titanite during deep burial of sedimentary rocks of Drahany Upland, Protivanov Formation. Detrital titanites and their alteration products were examined by electron microprobe. Titanite dissolution was observed from the rim and along the cracks, accompanied by the formation of an authigenic calcite, TiO2 phase, synchysite-(Ce), and rarely chlorite. With an increasing degree of alteration, detrital titanite occurs as small irregular relics inside a mixture of authigenic minerals. Based on the composition of authigenic minerals, we can suppose diagenetic fluid rich in CO2, F and Ca responsible for alteration of detrital titanite. The maximum temperatures in this area during deep burial of sedimentary rocks reached 250–300 °C, corresponding to the conditions of very low-grademetamorphism. Contents of REE (0.67–3.55 wt. % REE2O3) in detrital titanite are rather high and vary significantly. Authigenic synchysite-(Ce) compared with detrital titanite strongly prefers LREE over HREE, indicating that LREE released during dissolution of detrital titanite were preferentially incorporated into the structure of synchysite-(Ce), whereas HREE were mobilized and removed away by diagenetic fluids.

Authigenic Minerals in Carboniferous Sediments from Central Vestspitsbergen

1962 ◽  
Vol 99 (1) ◽  
pp. 63-68 ◽  
Author(s):  
Philip F. Hutchins
Keyword(s):  
Low Temperature ◽  
Sedimentary Rocks ◽  
Authigenic Minerals

AbstractPostdepositional low-temperature mineralogical changes in Carboniferous sedimentary rocks from Vestspitsbergen are described. These include the crystallization of apatite, quartz, and feldspar, and the replacement of feldspar and quartz by calcite and dolomite. Minerals of the chalcedonite–lutecime–quartzine group also occur.

Granite genesis related to geodynamics from Hf—Y in zircon

2000 ◽  
Vol 91 (1-2) ◽  
pp. 245-256 ◽  
Author(s):  
Jean-Pierre Pupin
Keyword(s):  
Phase 1 ◽  
Morphological Variability ◽  
Space Distribution ◽  
Accessory Mineral ◽  
Magmatic Zircon ◽  
Phase 2 ◽  
Genetic Groups ◽  
Magmatic Rocks ◽  
Chemical Variability ◽  
Definition Of

Zircon is a very interesting accessory mineral, a kind of ‘crustal diamond’, easily recycled and recording through large morphological variability the main rock-forming events. Since 1985, a systematic study of chemical variability of zircon in magmatic rocks has led to the definition of three main generations in zircon populations: inherited phase 1, magmatic phase 2 and late magmatic phase 3. Hafnium and yttrium appear to be the most useful for source characterisation, especially if using phase 2 data. As a consequence, a new diagram of HfO2versus Y2O3is proposed, divided into domains la to 6b to describe the distribution of the genetic groups and the specific domains for anorogenic and orogenic rocks. Zircon in anorogenic granitoids: tholeiitic plagiogranites (high Y, low Hf), hypersolvus (medium to low Y, low Hf) and subsolvus (medium to high Y and Hf) alkaline granites/rhyolites, has separate mean distributions. Genetic relations existing between rocks with obvious textural differences (granites, microgranites, rhyolites) are also recognised. Zircon in orogenic granitoids is Y-poor and shows a very limited distribution, but the minimal average values in magmatic zircon vary from 11 000 wt ppm HfO2in the calc-alkaline suite, to 12 000 ppm in the peraluminous porphyritic granites and to 13 500 ppm in entirely crustal anatectic granites and migmatites. Mixing-mingling processes are proposed to explain the intermediate characteristics of zircons and rocks in the peraluminous porphyritic and K-subalkaline granites. This is consistent with the time emplacement and space distribution of these two orogenic members, but leads to a new proposal of emplacement of some alkaline subsolvus magmas during orogenic cycles.

scholarly journals AUTHIGENIC MINERALS OF VOLCANOGENIC-SEDIMENTARY ROCKS OF THE PALEOZOIC–CENOZOIC AGE OF THE SOUTHERN PRIMORYE

2021 ◽  
Vol 40 (6) ◽  
pp. 100-110
Author(s):  
A.V. Mozherovsky ◽  
Keyword(s):  
Mixed Layer ◽  
Continental Margin ◽  
Sedimentary Rocks ◽  
Sedimentary Basins ◽  
Crustal Extension ◽  
Southern Primorye ◽  
Frequent Change ◽  
Authigenic Minerals ◽  
Volcanic Material ◽  
Sedimentation Basins

Authigenic minerals in volcanogenic-sedimentary and sedimentary rocks of Southern Primorye from Permian to Miocene time have been studied. Corrensite, rectorite, highly ordered mixed-layer differences of the chlorite-smectite (corrensite-like) and mica-smectite (rectorite-like) types, mica, vermiculite-like differences (?), chlorite, defective chlorite, kaolinite, smectite, calcite, and zeolites were found. Such a set of minerals indicates that the sedimentary layer in the studied sedimentary basins could be three to five kilometer thick, and the temperature of their formation is more than 150°C. The formation of the Lower Cretaceous and Paleocene sedimentary strata has similar features, and probably proceeded first in a shallow sea basin setting of the continental margin (rift stage), sometimes under conditions close to evaporitic (presence of corrensite?), with a frequent change of the facial situation from shallow to deep sedimentation, episodic supplies of volcanic material, and gradual deepening of sedimentation basins. It can be assumed that in Early Cretaceous and Paleogene times, a series of discrete sedimentation basins along the northeastern Asia continental margin developed in a single mineralogical, tectonic, and sedimentological regime of crustal extension: minerals accumulated in the sediments, which in the process of epigenesis transformed in the following directions: a) smectite-rectorite-mica; and b) smectite (palygorskite, sepiolite?) - corrensite-chlorite. In the studied sedimentary complexes three mineralogical «layers» are distinguished: 1) chlorite-mica – mica-chlorite (Permian - Cretaceous); 2) transitional from chlorite and mica to smectite - developed are corrensite, rectorite and highly ordered mixed-layer corrensite-like and rectorite-like minerals (Cretaceous - Paleocene-Eocene), and 3) smectite (from Oligocene to the present).

HRTEM Study of Zircon from Eliseev Anorthosite Complex, Antarctica

1996 ◽  
Vol 54 ◽  
pp. 668-669
Author(s):  
R. Wirth ◽  
H. Kämpf ◽  
A. Höhndorf
Keyword(s):  
Sedimentary Rocks ◽  
Age Determination ◽  
Radioactive Decay ◽  
Granulite Facies ◽  
Radioactive Isotopes ◽  
Accessory Mineral ◽  
Granulite Facies Metamorphism ◽  
Facies Metamorphism ◽  
Thorium Content ◽  
Anorthosite Complex

Zircon is a common accessory mineral in magmatic, metamorphic and sedimentary rocks. The crystal structure is tetragonal with space group I41/amd. Zircon contains minor amounts of U and Th and can be dated by a variety of techniques yielding ages of crystallization, cooling, and redistribution of radioactive isotopes and their daughter products. The precision of the radiogenic age determination strongly depends on the ability of zircon to retain the daughter products which were produced by the radiogenic decay of U and Th.Zircon-bearing rocks of this study are metamorphic oxide-apatite gabbronorites (OAGN) from the Eliseev Anorthosite Complex, Wohlthat-Massif, East Antarctica (Kampf et al., 1995). These unusual rocks are strongly enriched in accessory minerals (apatite: < 10 vol.%; zircon: < 1 vol.%, Owens & Dymek, 1992). Three steps in the evolution of these rocks are distinguished: a magmatic formation, followed by a granulite facies metamorphism and finally a tectonomagmatic overprint. The zircon crystals of this study are brown colored, up to 12 mm in length and up to 3 mm wide (Fig.1). Petrological investigations show that zircon has formed during the granulite facies event. Optical microscopy and cathodoluminiscence microscopy reveal a rhythmic zoning and many microcracks. The concentrations of uranium and thorium are low (U: 34-89 ppm and Th: 3-9 ppm). The radiation damage by radioactive decay of U and Th is expected to be minor due to the low uranium and thorium content.

Early Cenozoic partial melting of meta-sedimentary rocks of the eastern Gangdese arc, southern Tibet, and its contribution to syn-collisional magmatism

2021 ◽  
Author(s):  
Yuan-Yuan Jiang ◽  
Ze-Ming Zhang ◽  
Richard M. Palin ◽  
Hui-Xia Ding ◽  
Xuan-Xue Mo
Keyword(s):  
Partial Melting ◽  
Lower Crust ◽  
Sedimentary Rocks ◽  
Late Carboniferous ◽  
Southern Tibet ◽  
Magmatic Arc ◽  
Magmatic Rocks ◽  
Deep Crust ◽  
Juvenile Crust ◽  
Early Cenozoic

Continental magmatic arcs are characterized by the accretion of voluminous mantle-derived magmatic rocks and the growth of juvenile crust. However, significant volumes of meta-sedimentary rocks occur in the middle and lower arc crust, and the contributions of these rocks to the evolution of arc crust remain unclear. In this paper, we conduct a systematic study of petrology, geochronology, and geochemistry of migmatitic paragneisses from the eastern Gangdese magmatic arc, southern Tibet. The results show that the paragneisses were derived from late Carboniferous greywacke, and underwent an early Cenozoic (69−41 Ma) upper amphibolite-facies metamorphism and partial melting at pressure-temperature conditions of ∼11 kbar and ∼740 °C, and generated granitic melts with enriched Hf isotopic compositions (anatectic zircon εHf(t) = −10.57 to +0.78). Combined with the existing results, we conclude that the widely distributed meta-sedimentary rocks in the eastern Gangdese arc deep crust have the same protolith ages of late Carboniferous, and record northwestward-decreasing metamorphic conditions. We consider that the deeply buried sedimentary rocks resulted in the compositional change of juvenile lower crust from mafic to felsic and the formation of syn-collisional S-type granitoids. The mixing of melts derived from mantle, juvenile lower crust, and ancient crustal materials resulted in the isotopic enrichment of the syn-collisional arc-type magmatic rocks of the Gangdese arc. We suggest that crustal shortening and underthrusting, and the accretion of mantle-derived magma during the Indo-Asian collision transported the supracrustal rocks to the deep crust of the Gangdese arc.

scholarly journals Geochemistry, mineral chemistry and P-T evaluation of metasediments of Bahram-Gur complex, ES Sanandaj-Sirjan zone, Iran

Mineralogia ◽  
2019 ◽  
Vol 50 (1-4) ◽  
pp. 34-68
Author(s):  
Hadiseh Rahimi Sadegh ◽  
Hesam Moeinzadeh ◽  
Kazu Nakashima
Keyword(s):  
Continental Crust ◽  
Sedimentary Rocks ◽  
Mineral Chemistry ◽  
Amphibolite Facies ◽  
Southeastern Part ◽  
Metasedimentary Rocks ◽  
Magmatic Rocks ◽  
Sanandaj Sirjan Zone ◽  
Metamorphic Zone ◽  
Depositional Setting

AbstractThe Bahram-Gur area in the southeastern part of the Sanandaj – Sirjan metamorphic zone, contains metabasites and metasediments. The metasedimentary rocks are mainly garnet schists and garnet-staurolite schists that were metamorphosed under amphibolite facies conditions. The rocks consist of garnet ± staurolite, biotite, muscovite, chlorite and quartz. The geochemistry of the Bahram-Gur metasediments classifies them as quartziferous sedimentary rocks. The protoliths of the metasedimentary rocks were close to greywackes from an ensialic arc basin depositional setting, with a source comprising mostly mixture of acid and intermediate magmatic rocks in the upper continental crust. The metamorphic conditions of formation of the Bahram-Gur metasedimentary are investigated by geothermobarometric methods. The results show that the metasedimentary rocks formed at temperatures of 600-750°C and pressures of 5-7.5 kbar.

scholarly journals PŘIROZENÁ RADIOAKTIVITA KULMSKÝCH SEDIMENTŮ NA VÝCHODNÍM OKRAJI ČESKÉHO MASIVU

2012 ◽  
Vol 19 (1-2) ◽  
Author(s):  
Jiří Zimák
Keyword(s):  
Significant Contribution ◽  
Gamma Ray ◽  
Source Zone ◽  
Lower Carboniferous ◽  
Gamma Ray Spectrometer ◽  
Clay Shales ◽  
Magmatic Rocks ◽  
Clastic Sediments ◽  
Siliciclastic Sediments ◽  
High Radioactivity

Contents of potassium, uranium and thorium were measured using a laboratory gamma–ray spectrometer in more then two thousand samples of Upper Devonian to Lower Carboniferous siliciclastic flysch sediments outcropping on the easternmost margin of the Bohemian Massif (mainly in the Drahany Mts. and Nízký Jeseník Mts.). Studied rocks belong to eight formations: Protivanov Fm., Rozstání Fm., Myslejovice Fm., Mohelnice Fm., Andělská Hora Fm., Horní Benešov Fm., Moravice Fm. and Hradec–Kyjovice Fm. Conglomerates (incl. gravelites), various types of psammites (mainly graywackes), siltstones, silty shales and clay shales occur in all mentioned formations. Quartzites and phyllites dominated in the source zone of clastic sediments of Mohelnice Fm. and Andělská Hora Fm., therefore K, U and Th contents in siliciclastic sediments of the both formations are correspondingly low. Relatively high radioactivity of sediments belonging to remaining six formations suggests a significant contribution of acid or intermediate magmatic rocks in the source zone of clastic material.

scholarly journals Petrochemical study of Middle-Late Paleozoic sedimentary and metamorphic rocks near the great meandering of Tuul River, Central Mongolia

2019 ◽  
pp. 3-16
Author(s):  
Sodnom Khishigsuren ◽  
Nuramkhaan Manchuk ◽  
Ser-Od Tseden-Ish ◽  
Bayarmaa Batsaikhan
Keyword(s):  
Sedimentary Rocks ◽  
Major Elements ◽  
Orogenic Belt ◽  
Metamorphic Rocks ◽  
Education Development ◽  
X Ray ◽  
Central Mongolia ◽  
Magmatic Rocks ◽  
Upper Paleozoic ◽  
Continental Area

The great meandering of Tuul River is located in the Khentii section of the Khangai-Khentii orogenic belt, Central Mongolia. At the study area, dominanty distributed sedimentary and metamorphic roks of venlok-lower Devonian Sugnugur Formation of Asralt Khairkhan terrane and Pensilvanian Altan-Ovoo Formation of Ulaanbaatar terrane. The source of sedimentary rock are important to understand the geology and tectonic evoluation of the region. Whole-rock major elements compositions of 15 sandstone and mudrocks (siltstone and mudstone) and shale from the Sugnugur and Altan-Ovoo Formations were determind by X-ray fluorescence spectrometry at Nagoya University, Japan. Shale protolith of Sugnugur and Altan-Ovoo formations are terrigenous sedimentary rocks. The sandstone and mudstone of Sugnugur and Altan-Ovoo formations are almost similar to petrochemical properties, mostly of greywacke composition. The source of sandstone and mudstone of Altan-Ovoo Formation are the only silicic magmatic rocks, while the rocks of Sugnugur Formation are silicic magmatic rocks, with a mixture of quartz-sedimentary rocks, intermediate to mafic magmatic rocks. Sandstone and mudstone of Altan-Ovoo and Sugnugur formations are deposited in the active continental area by their petrochemical properties. These results support the results of the previous research on the Middle to Upper Paleozoic sedimentary rocks of the previous researcher's Khangai-Khentii orogenic belt. This study curried out funding of “Higher Engineering Education Development (M-JEED ) Project” and Nagoya University of Japan. Төв Монгол, Туулын их тохойрол орчмын дунд-дээд палеозойн тунамал, хувирмал чулуулгийн петрохими  Хураангуй: Туулын их тохойрол нь Төв Монголын Хангай-Хэнтийн ороген тогтолцооны Хэнтийн хэсэгт байрлана. Судалгааны талбайд Асралт хайрханы террейний венлок-доод девоны Сөгнөгөр ба Улаанбаатар террейний пенсилванийн Алтан-Овоо формацын тунамал, хувирмал чулуулгууд зонхилон тархдаг. Тунамал хурдсын эх үүсвэр, тектоник орчны судалгаа нь уг бүс нутгийн геологи, тектоникийн хөгжлийн түүхийг ойлгоход чухал ач холбогдолтой. Судалгаанд Сөгнөгөр формацын 9 ш, Алтан-Овоо формацын 6 ш алевролит, элсэн, чулуу, занар хамрагдав. Гол элементийн геохимийн шинжилгээг Японы Нагоягийн Их сургуулийн Геохимийн лабораторид рентген флюоресценцийн (XRF) аргаар хийлээ. Сөгнөгөр ба Алтан-Овоо формацын занарын протолит нь терриген тунамал чулуулаг байна. Сөгнөгөр ба Алтан-Овоо формацын алевролит, элсэн чулуу петрохимийн шинжээрээ ойролцоо, голдуу грауваккын найрлагатай байна. Алтан-Овоо формацын аргиллит, элсэн чулууны эх үүсвэр дан ганц хүчиллэг магмын чулуулаг, харин Сөгнөгөр формацынх хүчиллэг магмын чулуулгаас гадна багаар кварцын тунамал чулуулаг, дундлаг ба суурилаг магмын чулуулаг бүхий холимог найрлагатай байна. Сөгнөгөр ба Алтан-Овоо формацын чулуулгууд петрохимийн шинжээрээ эх газрын идэвхтэй захад хуримтлагдсан байна. Эдгээр үр дүн нь өмнөх судлаачдын Хангай-Хэнтийн ороген тогтолцооны дунд-дээд палеозойн тунамал чулуулагт хийсэн судалгааны үр дүнг дэмжиж байна. Судалгааны ажил нь Япон-Монголын хамтарсан M-JEED “1000 инженер” инженер технологийн дээд боловсрол төслийн санхүүжилтээр хийгдэв. Түлхүүр үг: Төв Азийн ороген бүс, элсэн чулуу, Улаанбаатар террейн, Асралт хайрхан террейн

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