The Evolution of Limestone and Dolomite. I
metamorphism of limestones after their emergence from the sea. Fineness of grain peculiar to some dolomites, probably indicative of very little metamorphism since deposition. Many …
اقرأ أكثر
3.8: Metamorphic Rocks
High-grade regional metamorphism of quartzofeldspathic rocks produces gneisses containing feldspar, quartz, biotite, and possibly hornblende. ... marble—marble is a metamorphic rock made up almost entirely of either calcite or dolomite, for which the protolith was either limestone or dolostone, respectively. Marbles may have bands of ...
اقرأ أكثر
Formation of Forsterite by Silicification of Dolomite during …
Four samples that experienced the infiltration-driven reaction 2 dolomiteþ SiO2(aq)1⁄4 forsteriteþ 2 calciteþ 2 CO2 exhibit correlations among forsterite crystal morphology, size, number density (number of Fo crystals per cm Fo), and oxygen isotope ratio (dO).The dO of coexisting forsterite, calcite, and dolomite were determined by in situ ion microprobe analysis …
اقرأ أكثر
Regional, Contact Metamorphism, and Autometamorphism of …
A terrane collage north of the Orso Zone revealed two stages of regional metamorphism: early-stage granulite metamorphism (Т = 750–900°С, Р = 8–9 kbar, around 500 Ma) and late-stage ...
اقرأ أكثر
(PDF) Very low- and low-grade Alpine regional metamorphism …
geo sync li ne-li ke anc hi-, epizonal fo rma ti ons m etamorphosed i n t he Hercyni an (Bret onian, Sud et an) te ct onophase s ( Szád ecz ky -K ardo ss et a h, 1969; N ag y a n d S zep eshá zy ...
اقرأ أكثر
10.4: Types of Metamorphism and Where They Occur
Regional metamorphism also takes place in this setting, and because of the extra heat associated with the magmatic activity, the geothermal gradient is typically steeper in these settings (between ~40 and 50 °C/km). Under these conditions, higher grades of metamorphism can take place closer to surface than is the case in other areas.
اقرأ أكثر
Calc-silicate marble
Impure dolomitic and calcitic limestone sediments may be metamorphosed by regional metamorphism; the regional metamorphism of such impure calcitic and dolomitic limestones produces a variety of silicate minerals. Dolomite limestones The P-T-X relationships of dolomite-rich marbles in orogenic belts are shown in Fig.1.
اقرأ أكثر
Resetting of Mg isotopes between calcite and dolomite …
The influences of diagenesis and burial metamorphism on dolomite rocks have been documented by Fantle and Higgins (2014) and Geske et al. (2012). The impact of diagenetic alteration on Mg isotope compositions of biogenic low-Mg calcite in brachiopod shell has been studied by Rollion-Bard et al. (2016) and Riechelmann et al. (2016) in detail ...
اقرأ أكثر
(PDF) Calcite-dolomite geothermometry applied to …
The calculated average temperature of the regional Alpine metamorphism in the carbonates reached 361 °C and 395-403 °C according to various calibrations, respectively. Discover the world's ...
اقرأ أكثر
Petrogenesis of Metamorphic Rocks
Preface This new edition of "Petrogenesis of Metamorphic Rocks" has several completely revised chapters and all chapters have updated references and redrawn figures.
اقرأ أكثر
Chapter 6 Metamorphism of Dolomites and Limestones
Metamorphism of Dolomites and Limestones 6.1 Introduction 6.1.1 Rocks Sedimentary carbonate rocks consist predominantly of carbonate minerals (as the ... stones. The first is modally dominated by dolomite (CaMg(CO 3) 2), the second by calcite (CaCO 3) and there is a complete gradation between the pure dolomite and limestone"end members ...
اقرأ أكثر
Calc-silicate marble
Impure dolomitic and calcitic limestone sediments may be metamorphosed by regional metamorphism; the regional metamorphism of such impure calcitic and dolomitic limestones produces a variety of silicate minerals. The P-T-X …
اقرأ أكثر
Con/regional and Metasomatic Rocks
CONTACT/REGIONAL AND METASOMATIC ROCKS Marble, Quartzite, and Serpentinite Marble is a metamorphic rock consisting of fine to coarse-grained recrystallized calcite and/or dolomite. It is often formed by metamorphosis of limestone and may be either contact or regional metamorphic rock intermediate in grad e between slate and mica schist. The ...
اقرأ أكثر
Metamorphism of Dolomites and Limestones | Request PDF
The paper aims to understand the effect of light-burned dolomite powders (LBD) on ordinary Portland cement (OPC) and evaluate the influence of LBD dosages and fineness …
اقرأ أكثر
Regional metamorphism and tectonic evolution of the …
The early Palaeozoic metamorphism occurred in two stages: (1) subduction zone metamorphism resulted in paired metamorphic belts in the Ondor Sum ophiolite and Bainaimiao island arc complex; and (2 ...
اقرأ أكثر
Original paper Origin and metamorphic evolution of …
during Variscan regional metamorphism. These authors supposed transformation of magnesite into talc during Al-pine metamorphism. In contrast, talc formation by contact and metasomatic process was assumed by Malachovský et al. (1992), Kilik (1997) and Turanová et al. (1997). Dianiška (1983) described low-temperature hornfelses,
اقرأ أكثر
Chapter 17: metamorphic rocks Flashcards
Regional metamorphism: When rocks are subjected to high pressures and temperatures over a large area, usually due to tectonic activity, they can undergo regional metamorphism. ... Skarn: Skarn is a type of metamorphic rock that forms from the alteration of carbonate rocks such as limestone or dolomite during contact metamorphism. It is ...
اقرأ أكثر
Metamorphism of Dolomites and Limestones | Request PDF
Field settings and chemical characteristics of the regional marbles (Tables 1 and 2, Figures 8,9,and 10) clearly indicate that they have been derived from regional metamorphism of...
اقرأ أكثر
Metamorphism of Dolomites and Limestones
20 in prograde metamorphism. ~ - 700 f -::;, ~ 600 CD c. E CD 1- 500 0 5 tremolite quartz 0.2 0.4 10 9 "C 8 OJ tn tn 7 c -OJ :;II;" 6 0" -I» .... 5 4 0.6 0.8 1.0 X co 2 Fig. 6.2. P-T-X phase relationships in dolomite marbles containing excess dolomite and cal cite. The vertical axis represents an orogenic geotherm characteristic of regional ...
اقرأ أكثر
Metamorphism of Dolomites and Limestones
Dolomites and dolomitic limestones will fall into category 1, limestones into either category 1 or 2 depending on the Dol!Qtz ratio of the rock. The boundary that separates the two compositional …
اقرأ أكثر
Petrographic and trace-element distribution studies on the dolomite …
Petrographic and trace-element distribution studies on the dolomite-calcite in the regional metamorphic marble of the Griesscharte, Tyrol, Austria/Italy ... 1921) was the first to map and study 82 the petrography of this series. The regional metamorphism of these marbles, termed by him (Sander, 1911) as "Tauern-Kristallisation", is of Alpine ...
اقرأ أكثر
Progressive Regional Metamorphism of Limestones
metamorphism, however, calcite in limestone may be transformed into aragonite. If an original limestone contains calcite and dolomite but no quartz, metamorphism may decompose only the dolomite as follows: dolomite --+ calcite + periclase + CO 2, This decomposition could take place at temperatures several
اقرأ أكثر
Multi-stage emerald formation during Pan-African regional metamorphism
The genesis of gem-quality deep green emeralds of Zabara, Sikait and Umm Kabo (South Eastern Desert, Egypt) is to date a controversial topic. The emerald-bearing biotite schists and quartz lenses ...
اقرأ أكثر
(PDF) The poteintial of forming Cu-Pb-Zn deposits …
The poteintial of forming Cu-Pb-Zn deposits during regional metamorphism: thermodynamic modeling and a case study on the Langshan-Zhaertai metallogenic belt (in Chinese with English abstract)
اقرأ أكثر
On the significance of short-duration regional metamorphism
Short-duration regional metamorphism is a recently observed and poorly understood phenomenon in metamorphic geology. In this review, it is defined as metamorphism on time scales that limit length scales (of the associated thermal anomaly) to significantly less than the thickness of the orogenic crust (<10 myr) or subducted oceanic lithosphere (<5 myr).
اقرأ أكثر
Muztaghata Dome Miocene Eclogite Facies Metamorphism: A …
Timing of peak metamorphism in the Muztaghata gneiss dome was ~25–20 Ma Peak metamorphic conditions reach HP-eclogite facies in the Muztaghata dome Early Miocene Pamir crust was thicker than presen. ... Y. P. Li, [email protected] Search for more papers by this author. Alexander C ... possibly driven in part by regional lithospheric delamination.
اقرأ أكثر
Regional Metamorphism
Metamorphism along low geothermal gradients results in a series of rocks that pass through the Zeolite, Prehnite-Pumpellyite, Blueschist, and Eclogite Facies of Regional …
اقرأ أكثر
Progressive Metamorphism of Siliceous Limestone and Dolomite
The metamorphism of siliceous dolomitic limestone is considered with the aid of a composition tetrahedron which suggests that the changes may be referred to thirteen steps or grades of increasing decarbonation, taking place at successively higher temperatures at any given pressure. At the temperature appropriate to each step a certain phase assemblage becomes unstable …
اقرأ أكثر
Regional Metamorphism
Regional Metamorphism Regional metamorphism is metamorphism that occurs over broad areas of the crust. Most regionally metamorphosed rocks occur in areas that have undergone deformation during an orogenic event resulting in mountain belts that have since been eroded to expose the metamorphic rocks. Barrovian Facies Series
اقرأ أكثر
Regional Metamorphism: Diagrams, Rocks, …
Most regional metamorphism takes place within continental crust.While rocks can be metamorphosed at depth in most areas, the potential for metamorphism is greatest in the roots of mountain ranges where there is a strong likelihood for …
اقرأ أكثر