Metamorphic development of cordierite-bearing layered schist and mica schist in the vicinity of Savonranta, eastern Finland

Halden, Norman M.; Bowes, D. R.

doi:10.17741/bgsf/56.1-2.001

Cited by 9 publications

(3 citation statements)

References 16 publications

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“…Both the ultramafic and pelite-based zones are sharply discordant with respect to the regional structural pattern. This fits well with the evidence for a late "static" culmination of the metamorphism evident from microstructures in both the metasedimentary and meta-ultramafic rocks (e.g., Koistinen, 1981;Treloar et al, 1981;Halden and Bowes, 1984; this study).…”

Section: Regional Mineral Assemblage Zones and Timing Of The Peak-metsupporting

confidence: 89%

Metamorphism and Chromite in Serpentinized and Carbonate-Silica-Altered Peridotites of the Paleoproterozoic Outokumpu-Jormua Ophiolite Belt, eastern Finland

Säntti

Kontinen

Sorjonen-Ward

et al. 2006

International Geology Review

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The 1.95 Ga Outokumpu-Jormua ophiolite belt of eastern Finland contains numerous mafic-ultramafic, predominantly peridotitic bodies which, despite amphibolite-facies metamorphism and pervasive deformation, retain compelling evidence of a residual mantle origin. These rocks therefore currently represent the oldest documented examples of exhumed mantle lithosphere, so information concerning their primary igneous mineral assemblages and textures and chemical and isotopic characteristics is of considerable scientific value. Although several earlier studies have argued for the preservation of primary mineral assemblages, field and petrographic evidence presented here show that the protolith peridotites had already experienced pervasive low-T serpentinization prior to Svecofennian orogenic deformation, during which they were progressively deserpentinized via antigorite metaserpentinites to olivine-talc-anthophyllite-enstatite-bearing metaperidotites. Evidence is also presented to show that the premetamorphic serpentinization event was closely followed by extensive low-T (< 250°C) metasomatic alteration of the marginal parts of the ultramafic bodies to carbonate-silica rocks which, during the subsequent prograde metamorphism, were converted to the distinctive chromite-bearing carbonate-skarn-quartz rocks comprising the Outokumpu rock assemblage. Because these quartz rocks are intimately associated with the Outokumpu Cu-Co-Zn-Ni deposits and have generally been regarded as metamorphosed siliceous seafloor exhalative deposits, the revised interpretation presented here has important implications for ore formation as well. Equilibrium mineral assemblages in the interior parts of the ultramafic bodies (low XCO 2 ) define four regional metamorphic zones, expressed as an east to west increase in the peak dehydration temperatures from 500° to 775ºC, at 3-5 kbar. Large ultramafic bodies commonly show core to margin zoning from talc via anthophyllite-to enstatite-bearing assemblages, reflecting synmetamorphic core-margin gradients in XCO 2 , attributed to infiltration of CO 2 released by decarbonation reactions in previously formed talc-carbonate and carbonate-silica alteration zones.The only primary igneous phase identified in this study was chromite, which occurs as scattered relict cores within large altered grains. These are relatively common in metaserpentinites, but also occur in metaperidotites and even in carbonate-skarn-quartz rocks. Even though Mg, Fe 2+ , and Zn abundances in these relict chromites may have been somewhat modified, absolute concentrations and ratios of Cr and Al appear to be essentially unmodified. The lobate to amoeboid morphology and observed Cr# range (0.41-0.67) of the best-preserved grains are more consistent with residual depleted lherzolite to harzburgite textures than a cumulate origin. However, during regional metamorphism, most mantle chromites were either pervasively altered to ferrian chromites and Cr-magnetites or (where CO 2 and S fugacities were high, such as within smaller ultramafic bod...

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Section: Regional Mineral Assemblage Zones and Timing Of The Peak-metsupporting

confidence: 89%

Metamorphism and Chromite in Serpentinized and Carbonate-Silica-Altered Peridotites of the Paleoproterozoic Outokumpu-Jormua Ophiolite Belt, eastern Finland

Säntti

Kontinen

Sorjonen-Ward

et al. 2006

International Geology Review

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“…Thus, as we see it, the pressure obtained, 4-5 kbar, is really lithostatic, and it is even possible that fluid pressure followed its own path at lower pressure. This interpretation is supported by metamorphic assemblages suggesting corresponding crystallization pressures in the neighbouring Palaeoproterozoic North Karelia Schist Belt (Koistinen 1981, Treloar et al 1981, Halden & Bowes 1984 and Kainuu Schist Belt (Tuisku & Laajoki 1990, Tuisku 1991. Because all the reactions described (e.g.…”

Section: Late-stage P-t Conditionsmentioning

confidence: 79%

Palaeoproterozoic prograde metasomatic-metamorphic overprint zones in Archean tonalitic gneisses, eastern Finland

Pajunen¹,

Poutiainen²

1999

Bull Geol Soc Finland

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Several occurrences of coarse-grained kyanite rocks are exposed in the Archaean area of eastern Finland in zones trending predominantly northwest-southeast that crosscut all the Archaean structures and, locally, the Palaeoproterozoic metadiabase dykes, too. Their metamorphic history illustrates vividly Palaeoproterozoic reactivation of the Archaean craton. The early-stage kyanite rocks were formed within the framework of ductile shearing or by penetrative metasomatism in zones of mobile brecciation. Static-state coarse-grained mineral growth during the ongoing fluid activity covered the early foliated fabrics, and metasomatic zoning developed. The early-stage metasomatism was characterized by Si, Ca and alkali leaching. The late-stage structures are dilatational semi-brittle faults and fractures with unstrained, coarsegrained fabrics often formed by metasomatic reactions displaying Mg enrichment along grain boundaries. Metamorphism proceeded from the low-T earlystage Chl-Ms-Qtz, Ky/And-St, eventually leading to the high-T late-stage Crd-Sil assemblages. The thermal peak, at 600-620°C/4-5 kbar, of the process is dated to 1852+2 Ma (U-Pb) on xenotime. Al-silicate growth successions in different locations record small variations in the Palaeoproterozoic clockwise P-T paths. Pressure decreased by c. 1 kbar between the early and late stage, i.e. some exhumation had occurred. Fluid composition also changed during the progression, from saline H,0 to CO, rich. Weak retrograde features of high-T phases indicate a rapid cooling stage and termination of fluid activity. The early-stage Ky-St assemblages resemble those described from nearby Palaeoproterozoic metasediments in the Kainuu and North Karelia Schist Belts, where the metamorphic peak was achieved late with respect to Palaeoproterozoic structures. The static Ky-St metamorphism in kyanite rocks was generated by fluid-induced leaching processes at elevated T during the post-orogenic stage after collision of the Palaeoproterozoic island arc complex with the Archaean craton in Palaeoproterozoic and/or reactivated Neoarchaean zones of weakness. The distribution of late-stage Crd-Sil metasomatism-metamorphism indicates that the corresponding thermal event was widespread in the Nurmes-Sotkamo area. Isotopic studies on Archaean granitoids and greenstone belts also indicate such late heating. According to pressure determinations, the Archaean±Palaeoproterozoic crust has been uplifted and exhumed about 15-20 km since 1850 Ma. Contemporaneous magmatic activation occurred in the North Karelia Schist Belt, too. The seismic deep structure of the crust, particularly the thick high-velocity layer in the lower crust, postulates some kind of disturbance in the lower crust

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“…Sandstone is used in a variety of Table 5. Chemical compositions of the stones (Cressman, 1962;Flower, 1973;Halden & Bowes, 1984;Ghalamghash et al, 2009;Bertetto et al, 2014) Siltstone is often used as a building material because it is relatively durable and easy to work with. Limestone is a sedimentary rock that is composed primarily of calcium carbonate.…”

Section: Stonementioning

confidence: 99%

Structural Analysis of Steel Truss and Masonry Bridge Interaction: A Case of Ali Fuat Pasha Bridge in Sakarya, Türkiye

Akşar

Ozdemir

Tutar

et al. 2023

Iğdır Üniversitesi Fen Bilimleri Enstitüsü Dergisi

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Restoration of historical structures using new materials and techniques is widespread worldwide. In these applications, relatively new materials such as steel, concrete, reinforced concrete (RC), or composite are generally preferred. However, it is often ignored whether old materials and new materials work in compatibility. In this respect, Ali Fuat Pasha Bridge (or Bayezid II Bridge), which was built by Bayezid II in 1495 over the Sakarya River in Geyve-Sakarya, was examined. The bridge is 196.50 meters long and consists of 15 arches with different spans and three arches of the bridge were destroyed as a result of the earthquake. Then, the bridge has been restored by constructing a steel truss system in place of the destroyed arches. Within the scope of this study, the structural performance of the bridge, which is currently serving vehicle and pedestrian traffic, is examined by using finite element analyses (FEAs). Moreover, this research examines the combined behavior of steel and masonry materials and investigates the structural behavior of steel truss and masonry bridge interaction. According to the results of the analyses, there are significant behavioral differences between the masonry structure and the steel structure. The main cause for this disparity is thought to be the varying levels of stiffness and ductility in steel and masonry sections.

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Metamorphic development of cordierite-bearing layered schist and mica schist in the vicinity of Savonranta, eastern Finland

Cited by 9 publications

References 16 publications

Metamorphism and Chromite in Serpentinized and Carbonate-Silica-Altered Peridotites of the Paleoproterozoic Outokumpu-Jormua Ophiolite Belt, eastern Finland

Metamorphism and Chromite in Serpentinized and Carbonate-Silica-Altered Peridotites of the Paleoproterozoic Outokumpu-Jormua Ophiolite Belt, eastern Finland

Palaeoproterozoic prograde metasomatic-metamorphic overprint zones in Archean tonalitic gneisses, eastern Finland

Structural Analysis of Steel Truss and Masonry Bridge Interaction: A Case of Ali Fuat Pasha Bridge in Sakarya, Türkiye

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