The 114 metabasites contain euhedral lawsonite laths in a matrix of foliated sodic amphibole with 115 variable amounts of phengite and chlorite. Calculated p t pseudosections show that the assemblage glaucophane pumpellyite chlorite occurs only in a restrictedfield along the lower p t limit of the blueschist facies. These sessions, entitled facies models revisited, were intended to capture the state of the art with respect to facies modeling in several key depositional environments. Pdf eclogite, amphibolite and blueschistfacies rocks from diego. Metamorphism and preservation of lawsonite eclogite, sivrihisar. Uncovering and quantifying the subduction zone sulfur. Temperatures of approximately 400 to 500 c 750 to 930 f and depths of about 8 to 50 kilometres 5 to 31 miles are the typical envelope of greenschist facies rocks. Just in case you forgot them over the last week, you can get a list by clicking here. Purple jade finelycrystalline jadeitekfeldsparlawsoniteaegerine metamorphite 10. Formation and subduction p12 5 p12 volume n 3 from do1 to p mesozoic ophiolites, showing peak blueschist metamorphic assemblages related to the alpine subduction. If your web browser has the proper plugin installed, clicking on the pdf will bring the file into your web browser from which you can then print the notes. Blueschisttogreenschist transition and the pt path of.
Such a lowp event caused a metamorphic zonation, with lower t. Geochemical and isotopic characteristics of blueschist facies. Rocks resulting from thermal contact metamorphism will. If the plugins are not installed, your web browser will either attempt to download the pdf files or offer to send you to the adobe web site to download the plugins for your browser. Bethghinivert, blueschist facies, calcschists, deformationmetamorphism. We present the first data on bulkrock major and trace element compositions for a suite of eclogite and blueschist facies rocks from the bantimala complex, indonesia, with the aim of better constraining the protolith origins and nature of the subducted c. Presentation mode open print download current view. It plays key roles in, for example, the redox evolution of the subarc mantle 1,2, the formation of ore deposits 2, and the composition of the. These two foliations were further folded by large folding during the mesoalpine event e. The protolith may be an aplite replaced by highpressure fluid of eclogite facies.
The path ebs to gs conditions followed under nearly isothermal uplift. In the catalina schist terrane, a nappe of blueschist facies melange is overlain by one of isoclinallyfolded greenschist facies rocks. Eclogiteblueschist relationships as evidenced by mineral. The pt history of the blueschistfacies metapelites is estimated using a simplified. The northern part of the cycladic island of sifnos greece is formed by a coherent sequence of interlayered acid and basic metavolcanic rocks and me. Blueschist facies article about blueschist facies by the. This study confirms the excellent work done by previous researchers e. Data sources and analytical methods many of the data presented here were obtained as part of a study of terrane correlations. Protolith 25 the blueschist facies is a metamorphic realm. After stacking and recrystallization under fairly comparable blueschistfacies conditions, the different sesia subunits underwent a lowp event of probable latealpine age.
Petrologic and geochemical comparison of the blueschist and. High pt sanbagawa or franciscan facies series facies series. Lawsonite, blueschist and eclogite formation in the southern. Metamorphic style and development of the blueschist. This unit is dominated by volcanoclastic sequences rich in mafic material with subordinate interbedding of metasediments, characterized by very fresh lawsonite blueschistfacies assemblages.
Lawsoniteomphacitebearing metabasites of the pam peninsula. Pdf hydrothermal blueschist facies zircons from the. Pdf ptt evolution of eclogiteblueschist facies metamorphism in. Structural context and variation of ocean plate stratigraphy, franciscan complex, california. The blueschist unit contains metagraywacke, metashale, metaconglomerate, greenstone, quartz schist, blueschist, and eclogite blocks in a finegrained, schistose matrix which probably recrystallized from a mixture of ultramafic and clayrich, quartzose detritus. Volcanic landforms and surface features pdf free download. Ductile thrusting recorded by the garnet isograd from blueschist. Felsic rocks and pelitic sediments which are subjected to blueschist facies conditions will form different mineral assemblages than metamorphosed basalt. Nine samples of blueschist facies metabasic rocks and four samples of associated metasedimentary lithologies were analysed for ree contents and nd isotopic composition.
Process of mineralogical and structural textural changes of rocks in the. The cenozoic tectonic history of the calabrian orogen. Blueschist metamorphism in an active subduction zone nature. Metamorphic style and development of the blueschist to. Conference of the canadian society of petroleum geologists and in dallas in 2004 annual conference of the american association of petroleum geologists. Blueschist facies metamorphism is important in subduction zones, where highpressure, relatively lowtemperature mineral assemblages form. If the file has been modified from its original state, some details such as the timestamp may not fully reflect those of the original file.
In the western himalaya, the best occurrence of blueschist is that of the sapishergol ophiolitic melange in ladakh. Whereas blueschist epidotes show very high fe content 79. Geochemistry of eclogite and blueschistfacies rocks from the bantimala complex, south. Miyashiro 1961 proposed five facies series simplified to. White mica, chlorite and quartz predominate in the phyllites in variable proportions, but na amphibole, epidote, albite and titanite may also be important. The development of a pervasive blueschistfacies d2foliation is in contrast with the eclogitic dominant fabric generally recorded in the emc. This difference suggests that fe and mt are potentially responsible for kmscale heterogeneities in the tectonometamorphic record. Facies represent specific temperature pressure regimes. Use these facies if clearly associated with a pluton. Announcements look here during the semester for announcements concerning this course. Eclogiteblueschistfacies rocks from spouthern sifnos.
Blueschist facies an overview sciencedirect topics. More recently the term blueschist facies has been preferred because glaucophane is not always developed in many important rock types, for example, graywacke sandstones, which may contain other minerals that are characteristic of high pressure and low temperature such as. A maximum depositional age of 6 ma demonstrates that the liberty creek schist was deposited long after the jurassic cooling ages 196185 ma. Correlation of the klamath mountains and sierra nevada.
Named for equivalent mafic rock type at those conditions. Each of these units bears the imprint of blueschist facies metamorphism, indicating that it has been subducted to. Klippen of analogous blueschist terrains cravascovoltaggiomontenotte units also overlie the eclogitic. Hydrothermal blueschist facies zircons from the franciscan complex, california. Geochemistry of eclogite and blueschistfacies rocks from. Blueschist accessscience from mcgrawhill education. Implications for the early exhumation of highpressure rocks.
A link within the document will lead you to a pdf file geared for printing this list. Protolith 25 the blueschist facies is a metamorphic realm of. A greenschist protolith for blueschist in anglesey, u. Yes, you will have to know the chemical formulae for the common minerals again this semester. Petrology of blueschist from the western himalaya ladakh, nw. Condie, in earth as an evolving planetary system, 2005. This report graphically portrays the broadly parallel tectonic development of the klamath mountains and sierra nevada from early paleozoic to early cretaceous time. Thereby, these rocks do not appear blue overall in color. Sulfur is one of the most common volatiles on earth. Epidotes in both greenschist and blueschist show fedepleted rims. Rocks which contain certain minerals can therefore be linked to certain tectonic settings.
The calculated pt conditions of the eclogite facies metamorphism are t500c and. These rocks were affected by a widespread blueschistfacies metamorphic event, presumably of triassic age. Graduate thesis or dissertation structure and petrography. Correlation of the klamath mountains and sierra nevada usgs. The cenozoic accretionary wedge of calabria, southern italy, consists of several units of continental and oceanic affinity accreted beneath the former continental margin of the sardiniacorsica block. Metamorphic rocks formed by regional metamorphism in the following condition. Eclogite facies metamorphism in sugozu nappe, which consists of. In glaucophanites synd1 and synd2 parageneses, associated with s1 and s2 schistosities, indicate epidote blueschist facies conditions. Distribution of metamorphic rocks subjected to blueschist facies regional metamorphism described in this site. Blueschist blocks within the schistose matrix reveal six deformation events, d1d6. Analysis of fabric evolution and metamorphic reaction. Blueschist facies is determined by the particular temperature and pressure conditions required to metamorphose basalt to form blueschist. Cordilleran section 109th annual meeting 2022 may 20. Good exposures of the blockinmatrix fabric of the fjt exist in the soap creek valley, just west of yreka.
Metamorphic style and development of the blueschist to eclogitefacies rocks, cyclades, greece john c schumacher1, john b brady2, john t cheney3 1dept. Until now, however, the link between blueschist facies rocks and subduction zones has been indirect, relying on a spatial association of blueschists with old subduction complexes, and estimates of. Detrital zircon data are presented from the liberty creek blueschist in the central chugach mountains which indicate two distinct periods of the preservation of blueschist facies metamorphism along the southern alaskan margin. This file contains additional information such as exif metadata which may have been added by the digital camera, scanner, or software program used to create or digitize it.
Home anu research anu scholarly output anu research publications geochemistry of eclogite and blueschistfacies rocks from the bantimala complex, south sulawesi, indonesia. A curious, and confusing, feature is the inclusion of two maps for each of the california areas studied, one by the. Sampling includes the main rock types exposed on groix, concentrating on those metabasic rocks with least dispersed rbsr sys. Structural and geochronologic history of southern alaskan. Pseudosections also indicate that peak p t conditions for the blueschist samples studied here lie in the range 6. Petrologic and geochemical comparison of the blueschist. A pt path for the prasinites is presented indicating epidote blueschist facies at pt conditions of around 7. The posteclogitic t decrease inferred here for the southern em is less evident in more northerly parts of this subunit. Upb dating of zircon from the orthogneiss and a metavolcanic schist indicates a middle jurassic age helper and others, 1989.
Lawsonite, blueschist and eclogite formation in the. Condie, in earth as an evolving planetary system second edition, 2011. Amphibolite facies includes calcite marbles, biotite schists and amphibolites. These rocks tectonically overlie intact lower grade units including a blueschist facies unit with abundant metavolcanics mov and metachert s in addition. Early carboniferous blueschist facies metamorphism in. Geochemical and isotopic characteristics of blueschist. Read transitional blueschistepidote amphibolite facies metamorphism in the frankenberg massif, germany, and geotectonic implications, journal of metamorphic geology on deepdyve, the largest online rental service for scholarly research with thousands of academic publications available at your fingertips. Highpressure, lowtemperature metamorphism associated with subduction zones which produces a broad mineral association including glaucophane, actinolite. We present the first data on bulkrock major and trace element compositions for a suite of eclogite and blueschistfacies rocks from the bantimala complex, indonesia. Metamorphic evolution of blueschists, greenschists, and. Pdf geochemistry of eclogite and blueschistfacies rocks.
Pdf early carboniferous blueschist facies metamorphism in. Petrology of blueschist from the western himalaya ladakh. Eclogites and blueschist facies rocks are frequent in the eastern part of the island, whereas greenschist facies rocks are. Pdf few localities in the patagonian andes expose remnants of the mesozoic chilean paleoaccretionary complex. Permission is hereby granted to any individual scientist to download a single copy of this electronic file and reproduce up to. Lowtemperature blueschistfacies mafic blocks in the franciscan melange, san simeon, california. An oligocene extrusion wedge of blueschistfacies nappes on evia island, aegean sea, greece. Blueschist facies metamorphic rocks are in franciscantype highp metamorphic rocks. Until now, however, the link between blueschistfacies rocks and subduction zones has been indirect, relying on a spatial association of blueschists with. Metamorphic facies the metamorphic facies are groups of mineral compositions in metamorphic rocks, that are typical for a certain field in pressuretemperature space. I first used the term blueschist in 1961 and defined blueschist facies as including the rocks formed in the stability. A final reequilibration under greenschists facies conditions, locally associated to s3 crenulation cleavage and replacement of synd1 and synd2 assemblages, is recorded in all metabasites fig.
The white schist assemblage in the kyanite quartzite from the. This file may not be posted to any web site, but authors may post the abstracts only of their articles on their own or their organizations web site providing the posting includes a reference to the articles full citation. The groupii fluid inclusions formed at blueschistfacies conditions support the idea that aqueous fluids in the subduction channel have a salinity similar to. The blueschist metamorphic facies are characterized by the minerals jadeite, glaucophane. Stepheating 40ar39ar spectra were obtained for mica from several lenses of blueschists including greenschist facies rocks. Metamorphic conditions which create typical greenschist facies assemblages are called the barrovian facies sequence, and the lowerpressure abukuma facies series.
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