Relative Contributions of Precambrian Metamorphic Rocks and Cretaceous-Tertiary Igneous Rocks to Oligocene and Holocene Fluvial Sands and the Unroofing of a Magmatic Arc

AAPG Bulletin ◽  
1991 ◽  
Vol 75 ◽  
Author(s):  
MOLINAROLI, EMANUELA, and ABHIJIT B
Keyword(s):  
Igneous Rocks ◽  
Metamorphic Rocks ◽  
Magmatic Arc

Revised stratigraphy of the Mesozoic rocks of southern Cyprus

1980 ◽  
Vol 117 (6) ◽  
pp. 547-563 ◽  
Author(s):  
R. E. Swarbrick ◽  
A. H. F. Robertson
Keyword(s):  
Oceanic Crust ◽  
Continental Margin ◽  
Late Cretaceous ◽  
Sedimentary Cover ◽  
Igneous Rocks ◽  
Late Triassic ◽  
Metamorphic Rocks ◽  
Southern Cyprus

SummaryRecent resurgence of interest in the Mesozoic rocks of SW and southern Cyprus necessitates redefinition of the Mesozoic sedimentary and igneous rocks in line with modern stratigraphical convention. Two fundamentally different rocks associations are present, the Troodos Complex, not redefined, a portion of late Cretaceous oceanic crust, and the Mamonia Complex, the tectonically dismembered remnants of a Mesozoic continental margin. Based on earlier work, the Mamonia Complex is divided into two groups, each subdivided into a number of subsidiary formations and members. The Ayios Photios Group is wholly sedimentary, and records the evolution of a late Triassic to Cretaceous inactive continental margin. The Dhiarizos Group represents Triassic alkalic volcanism and sedimentation adjacent to a continental margin. Several other formations not included in the two groups comprise sedimentary mélange and metamorphic rocks. The Troodos Complex possesses an in situ late Cretaceous sedimentary cover which includes two formations of ferromanganiferous pelagic sediments, radiolarites and volcaniclastic sandstones. The overlying Cainozoic calcareous units are not redefined here.

Lower Palaeozoic and Precambrian igneous rocks from eastern England, and their bearing on late Ordovician closure of the Tornquist Sea: constraints from U-Pb and Nd isotopes

1993 ◽  
Vol 130 (6) ◽  
pp. 835-846 ◽  
Author(s):  
S. R. Noble ◽  
R. D. Tucker ◽  
T. C. Pharaoh
Keyword(s):  
Volcanic Rocks ◽  
Igneous Rocks ◽  
Calc Alkaline ◽  
Nd Isotopes ◽  
Nd Isotope ◽  
Magmatic Arc ◽  
The North ◽  
Basement Rocks ◽  
Continental Arc ◽  
Lower Palaeozoic

AbstractThe U-Pb isotope ages and Nd isotope characteristics of asuite of igneous rocks from the basement of eastern England show that Ordovician calc-alkaline igneous rocks are tectonically interleaved with late Precambrian volcanic rocks distinct from Precambrian rocks exposed in southern Britain. New U-Pb ages for the North Creake tuff (zircon, 449±13 Ma), Moorby Microgranite (zircon, 457 ± 20 Ma), and the Nuneaton lamprophyre (zircon and baddeleyite, 442 ± 3 Ma) confirm the presence ofan Ordovician magmatic arc. Tectonically interleaved Precambrian volcanic rocks within this arc are verified by new U-Pb zircon ages for tuffs at Glinton (612 ± 21 Ma) and Orton (616 ± 6 Ma). Initial εNd values for these basement rocks range from +4 to - 6, consistent with generation of both c. 615 Ma and c. 450 Ma groups of rocksin continental arc settings. The U-Pb and Sm-Nd isotope data support arguments for an Ordovician fold/thrust belt extending from England to Belgium, and that the Ordovician calc-alkaline rocks formed in response to subductionof Tornquist Sea oceanic crust beneath Avalonia.

Gneiss, marbres, prasinites en coussins et polymetamorphisme dans la partie sud-occidentale du massif Dora-Maira (Alpes cottiennes piemontaises)

1961 ◽  
Vol S7-III (4) ◽  
pp. 345-354
Author(s):  
Andre Michard ◽  
P. Vialon
Keyword(s):  
White Mica ◽  
Igneous Rocks ◽  
Metamorphic Rocks ◽  
Retrograde Metamorphism ◽  
Po River ◽  
Alpine Metamorphism

Abstract Igneous rocks of the Dora-Maira massif in the Po river headwater region in the Cottian Alps of Piedmont, Italy, are surrounded, and in many places surmounted, by gneiss, marble, and other associated metamorphic rocks of controversial age. The evidence is considered conclusive that the age of the rocks ranges from Permo-Carboniferous to Triassic. Criteria for discrimination of successive periods of metamorphism, including retrograde metamorphism, are reviewed. Carbonatized rocks and phengitic conglomeratic quartzite serve as "metamorphic thermometers" useful locally for discriminating successive periods of metamorphism. Cataclastic effects are also useful for determining time relationships, as are also optical peculiarities of quartz, feldspar, white mica, and biotite in various rocks. It is concluded that the region has been subjected to two major periods of metamorphism, and that the Alpine metamorphism in general was less intensive, and in certain aspects was retrograde compared with the pre-Alpine metamorphism.

Variety and genesis of the pyroxene-bearing S- and I-type granitoids from the Hidaka Metamorphic Belt, Hokkaido, northern Japan

2004 ◽  
Vol 95 (1-2) ◽  
pp. 161-179 ◽  
Author(s):  
Toshiaki Shimura ◽  
Masaaki Owada ◽  
Yasuhito Osanai ◽  
Masayuki Komatsu ◽  
Hiroo Kagami
Keyword(s):  
Partial Melting ◽  
Granulite Facies ◽  
Mafic Granulite ◽  
Granitic Rocks ◽  
Metamorphic Rocks ◽  
Metamorphic Belt ◽  
Model Calculations ◽  
Magmatic Arc ◽  
River Region ◽  
Northern Japan

ABSTRACTThe high-dT/dP-type Hidaka Metamorphic Belt in Hokkaido, northern Japan, represents a tilted crustal section of a magmatic arc of Tertiary age. The highest metamorphic grades reached are granulite facies, and the syn-metamorphic granitic rocks are widely distributed in this metamorphic terrane. The granitic rocks are mainly tonalitic and granodioritic in composition, and are classified into peraluminous (S-type) and metaluminous (I-type) granitoids. A large amount of pyroxene-bearing S-type tonalites (garnet-orthopyroxene tonalite) is distributed in the Niikappu river region in the northern part of the Hidaka Metamorphic Belt. Pyroxene-bearing I-type tonalite (two-pyroxene hornblende tonalite) bodies are also distributed in this area.The pyroxene-bearing tonalites are classified into several sub-types on the basis of their field occurrence, texture, mineral assemblage and geochemical features. Homogeneous IH- and SH-type tonalite are thought to represent original magmas, i.e. those which have been generated by partial melting of mafic metamorphic rocks and pelitic-psammitic metamorphic rocks, respectively. Model calculations assuming batch partial melting indicate that possible restites are garnet-two-pyroxene mafic granulite for IH-type and garnet-orthopyroxene aluminous granulite for SH-type. The unexposed lowermost crust of the ‘Hidaka crust’ is thought to be composed of garnet-two-pyroxene mafic granulite, garnet-orthopyroxene aluminous granulite and metagabbros.

Significance of “gneissic” rocks in the Liscomb Complex, Nova Scotia

2010 ◽  
Vol 47 (6) ◽  
pp. 927-940 ◽  
Author(s):  
J. V. Owen ◽  
R. Corney ◽  
J. Dostal ◽  
A. Vaughan
Keyword(s):  
Igneous Rocks ◽  
Metamorphic Rocks ◽  
Low Grade ◽  
High Grade ◽  
Peraluminous Granite ◽  
Isotopic Signatures ◽  
Conventional View ◽  
Basement Rocks ◽  
Mineral Assemblages ◽  
Intrusive Rocks

The Liscomb Complex comprises Late Devonian intrusive rocks (principally peraluminous granite) and medium- to high-grade metamorphic rocks (“gneisses”) that collectively are hosted by low-grade (greenschist facies) metasediments of the Cambro-Ordovician Meguma Group. The conventional view that these “gneisses” contain high-grade mineral assemblages and represent basement rocks has recently been challenged, and indeed, some of the rocks previously mapped as gneisses, particularly metapelites, have isotopic compositions resembling the Meguma Group. Amphibole-bearing enclaves in the Liscomb plutons, however, are isotopically distinct and in this regard resemble xenoliths of basement gneisses in the Popes Harbour lamprophyre dyke, south of the Liscomb area. Metasedimentary enclaves with Meguma isotopic signatures can contain garnets with unzoned cores (implying high temperatures) that host high-grade minerals (prismatic sillimanite, spinel, and (or) corundum) and are enclosed by retrograde-zoned rims. These features are interpreted here as having formed during and following the attainment of peak temperatures related to Liscomb magmatism. The amphibole-bearing meta-igneous rocks described here contain cummingtonite or hornblendic amphibole and occur as enclaves in granodioritic to tonalitic plutons. They are mineralogically, texturally, and isotopically distinct from Meguma metasediments and at least some of the plutonic rocks that enclose them, so remain the most likely candidate for basement rocks in the Liscomb Complex.

scholarly journals APATITE-ALBITE METASOMATITES (ACEITES) OF THE EASTERN ALDAN-STANOVOY SHIELD

2021 ◽  
Vol 40 (5) ◽  
pp. 59-73
Author(s):  
V.E. Kirillov ◽  
Keyword(s):  
Rare Earth ◽  
Structural Control ◽  
Earth Element ◽  
Rare Metal ◽  
Igneous Rocks ◽  
Metamorphic Rocks ◽  
Intrusive Rocks ◽  
Characteristic Features ◽  
Metasomatic Zoning ◽  
Geochemical Specialization

The paper summarizes the findings of research on Riphean ore-bearing apatite-albite metasomatites (aceites) identified in metamorphic, volcanic and intrusive rocks in the eastern Aldan-Stanovoy shield. The characteristic features of lithological and structural control of aceites, their mineral and petrochemical composition, geochemical associations, ontogeny, metasomatic zoning, and geochemical specialization are outlined. Aceites in metamorphic rocks are assigned to the albite-chlorite-apatite facies and in igneous rocks to the albite-apatite facies. Apatite-albite metasomatites host mineralization of two types: uranium (in aceites after metamorphic rocks) and uranium – rare earth element – rare metal (in aceites after volcanic and intrusive rocks).

scholarly journals Pétrographie characterization of rocks from the Mirabello bay region, Crete, and its application to Minoan archaeology: the provenance of stone implements from Minoan sites

2007 ◽  
Vol 40 (4) ◽  
pp. 1768 ◽  
Author(s):  
H. M. Dierckx ◽  
B. Tsikouras
Keyword(s):  
Raw Materials ◽  
Igneous Rocks ◽  
Metamorphic Rocks ◽  
Rock Samples ◽  
Rock Types ◽  
Source Regions ◽  
Time Period

The Minoans of East Crete used a variety of igneous and metamorphic rocks as stone implements. These were probably procured in dry riverbeds and beaches located in a region along the Bay of Mirabello or from an onlap conglomerate, which geologically dominates that region and contains rock types of igneous, metamorphic and sedimentary origin. Several rock samples were collected for pétrographie investigation to examine and confirm the source for the igneous rocks. Detailed pétrographie description of natural samples provides the identification of the rocks employed by Minoans and confirms the source of their origin. Apparently the Minoans were able to evaluate the hardness of the stones procured according to the desirable usage and their expected fatigue, thus avoiding unnecessary timeconsuming treatment. The identification of the variable lithotypes used for these implements and the verification of their source regions reveal the time it took to procure the raw materials as well as the time period during which the rocks were employed.

scholarly journals Rock Types Classification and Distribution on Anabanua Village, Barru Regency, South Sulawesi

2020 ◽  
Vol 8 (1) ◽  
pp. 1-8
Author(s):  
Muhammad Resky Ariansyah ◽  
Muhammad Fawzy Ismullah Massinai ◽  
Muhammad Altin Massinai
Keyword(s):  
Sedimentary Rocks ◽  
Research Area ◽  
Igneous Rocks ◽  
The Other ◽  
Metamorphic Rocks ◽  
Geological Process ◽  
Rock Types ◽  
South Sulawesi ◽  
Geological Conditions ◽  
Limestone Sand

Anabanua Village, Barru Regency is one of the areas in South Sulawesi that has quite unique geological conditions. This condition inseparably comes from the complicated geological process that took place during the formation of the island, Sulawesi. In Anabanua Village, there are many types of rocks such as sedimentary rocks, metamorphic rocks and igneous rocks. This paper aims to map and classify the types of rock by taking samples on different places in the research area. Then we observe the samples physical properties. The results showed, from taking 10 rock samples in different places, they have various characteristics. 8 of them were sedimentary rocks, they are Limestone Quartz, Limestone Sand, Shale, Sandstone, Coal, Limestone Bioturbation, Breccia, and Chert Stone. The other 2 samples were metamorphic rocks, they are Greenschist and Quartzite.

scholarly journals Chemical Analyses of Igneous and Metamorphic Rocks of Denmark, the Faeroes and Greenland. (To and including 1940)

1942 ◽  
Vol 68 ◽  
pp. 1-105
Author(s):  
Sole Munck ◽  
Arne Noe-Nygaard
Keyword(s):  
Comparative Study ◽  
Igneous Rocks ◽  
Geological Survey ◽  
Metamorphic Rocks ◽  
Chemical Analyses ◽  
The Past ◽  
De Quervain ◽  
Set Up ◽  
The Comparative Study

The past ten years or so have seen the publication of collections of chemical rock analyses which, as a result of their clear form of set-up, in many ways faciliate the comparative study of the chemistry of the rocks and their mutual relationships. Among these publications there are: P. Niggli, F. De Quervain & R. U. Wintherthalter: Chemismus schweizerischer Gesteine. Bern 1930, and the analyses publish ed by the Geological Survey of Great Brita in: Chemical Analyses of Igneous Rocks, Metamorphic Rocks and Minerals. London 1931. Similar publications are available from two neighbouring countries, i.e. from Sweden: W. Larsson: Chemical Analyses of Swedish Rocks (Bull. Geol. Inst., Uppsala 1932) and from Finland : L. Lokka: Neuere Chemische Analysen von Finnisch en Gesteinen (Bull. Comm. Geol. de Finlande No. 105. Helsingfors 1934).

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