Neoproterozoic magmatic arc volcanism in the Borborema Province, NE Brazil: possible flare-ups and lulls and implications for western Gondwana assembly

2020 ◽  
Author(s):  
Fabrício Andrade Caxito ◽  
Camila Franco Basto ◽  
Lauro Cézar Montefalco de Lira Santos ◽  
Elton Luiz Dantas ◽  
Vladimir Cruz de Medeiros ◽  
...  
Keyword(s):  
Arc Volcanism ◽  
Magmatic Arc ◽  
Borborema Province ◽  
Western Gondwana Assembly ◽  
Neoproterozoic Magmatic Arc

scholarly journals Provenance and Sedimentary Context of Clay Mineralogy in an Evolving Forearc Basin, Upper Cretaceous-Paleogene and Eocene Mudstones, San Joaquin Valley, California

Minerals ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 71
Author(s):  
Andrew Hurst ◽  
Michael Wilson ◽  
Antonio Grippa ◽  
Lyudmyla Wilson ◽  
Giuseppe Palladino ◽  
...  
Keyword(s):  
Phase Transitions ◽  
Upper Cretaceous ◽  
Clay Fraction ◽  
Clay Mineralogy ◽  
Bulk Rock ◽  
X Ray Diffraction ◽  
Arc Volcanism ◽  
X Ray ◽  
Magmatic Arc ◽  
Tropical Weathering

Mudstone samples from the Moreno (Upper Cretaceous-Paleocene) and Kreyenhagen (Eocene) formations are analysed using X-ray diffraction (XRD) and X-ray fluorescence (XRF) to determine their mineralogy. Smectite (Reichweite R0) is the predominant phyllosilicate present, 48% to 71.7% bulk rock mineralogy (excluding carbonate cemented and highly bio siliceous samples) and 70% to 98% of the <2 μm clay fraction. Opal CT and less so cristobalite concentrations cause the main deviations from smectite dominance. Opal A is common only in the Upper Kreyenhagen. In the <2 μm fraction, the Moreno Fm is significantly more smectite-rich than the Kreyenhagen Fm. Smectite in the Moreno Fm was derived from the alteration of volcaniclastic debris from contemporaneous rhyolitic-dacitic magmatic arc volcanism. No tuff is preserved. Smectite in the Kreyenhagen Fm was derived from intense sub-tropical weathering of granitoid-dioritic terrane during the hypothermal period in the early to mid-Eocene; the derivation from local volcanism is unlikely. All samples had chemical indices of alteration (CIA) indicative of intense weathering of source terrane. Ferriferous enrichment and the occurrence of locally common kaolinite are contributory evidence for the intensity of weathering. Low concentration (max. 7.5%) of clinoptilolite in the Lower Kreyenhagen is possibly indicative of more open marine conditions than in the Upper Kreyenhagen. There is no evidence of volumetrically significant silicate diagenesis. The main diagenetic mineralisation is restricted to low-temperature silica phase transitions.

scholarly journals A preserved early Ediacaran magmatic arc at the northernmost portion of the Transversal Zone central subprovince of the Borborema Province, Northeastern South America

2016 ◽  
Vol 46 (4) ◽  
pp. 491-508 ◽  
Author(s):  
Benjamim Bley de Brito Neves ◽  
◽  
Edilton José dos Santos ◽  
Reinhardt Adolfo Fuck ◽  
Lauro César Montefalco Lira Santos ◽  
...  
Keyword(s):  
Granitic Rocks ◽  
Lower Plate ◽  
Low Grade ◽  
Northeast Brazil ◽  
The South ◽  
Magmatic Arc ◽  
Continental Plate ◽  
Borborema Province ◽  
Northern Portion ◽  
Fold Belts

ABSTRACT: Magmatic arcs are an essential part of crust-forming events in planet Earth evolution. The aim of this work was to describe an early Ediacaran magmatic arc (ca. 635-580 Ma) exposed in the northernmost portion of the Transversal Zone, central subprovince of Borborema Province, northeast Brazil. Our research took advantage of several syntheses by different authors, including theses and dissertations, carried out on magmatic rocks of the study area for the last 30 years. The ca. 750 km long and up to 140 km wide arc, trending ENE-WSW, is preserved to the south of the Patos Lineament, between 35º15' and 42º30'W and 7º15' and 8ºS. About 90 different stocks and batholiths of I-type granitic rocks were mapped along this orogenic zone, preferentially intruding low-grade schists of the Cryogenian-Ediacaran Piancó-Alto Brígida (SPAB) belt. Three igneous supersuites are recognized: a) epidote-bearing granodiorites and tonalites ("Conceição" type); b) high-K calc-alkaline granites ("Itaporanga" type); c) biotite granodiorites of trondhjemite affinity ("Serrita" type). A fourth group of peralkalic and shoshonitic rocks occurs to the south of the previous ones, reflecting special tectonic conditions. NNE-SSW trending Paleoproterozoic fold belts, surrounding Archean nuclei, characterize the continental part of the northern lower plate. The oceanic fraction of this lower plate was recycled by subduction and scarce remnants of which may be seen either within the enclosing low-grade schists or as xenoliths within the arc intrusions. The upper continental plate presents WSW-ENE structural trends and is composed of Neoproterozoic fold belts and Paleoproterozoic reworked basement inliers. Available data bear clear evidence of an Ediacaran magmatic arc built at the northern portion of the Transversal Zone in the Borborema Province, northeast Brazil.

Upper Cretaceous Stratigraphy and Volcanism in the İğneada region, Pontides, NW Turkey

2020 ◽  
Author(s):  
Ezgi Sağlam ◽  
Turgut Duzman ◽  
Aral I. Okay
Keyword(s):  
Upper Cretaceous ◽  
Planktonic Foraminifera ◽  
Lava Flows ◽  
Arc Volcanism ◽  
Magmatic Arc ◽  
Andesitic Lava ◽  
Black Sea Coast ◽  
Nw Turkey ◽  
Sandy Limestone ◽  
Volcaniclastic Rocks

&lt;p&gt;The Pontide Upper Cretaceous magmatic arc can be traced for over 1000 km along the southern Black Sea coast from Georgia to Bulgaria. &amp;#160;The arc extrusive sequence is well-exposed in the &amp;#304;&amp;#287;neada region in Thrace close to the Bulgarian border. The Upper Cretaceous sequence in &amp;#304;&amp;#287;neada region overlies the schists and phyllites of Strandja Massif with an unconformity. It &amp;#160;has a thickness of over 700 meters and consists at the base of Cenomanian shallow marine sandy limestone, which pass up into pelagic limestone, marn and volcanogenic siltstone with Turonian planktonic foraminifera, including &lt;em&gt;Marginotruncana pseudolinneana&lt;/em&gt;, &lt;em&gt;Marginotruncana marginata&lt;/em&gt;, &lt;em&gt;Whitenella&lt;/em&gt; sp., &lt;em&gt;Whitenella praehelvetica&lt;/em&gt;, &lt;em&gt;Muricohedbergella&lt;/em&gt; sp.&amp;#160; This indicates that the arc volcanism in the region started in the Turonian. The pelagic limestone, marl, and calcareous siltstone series passes up into a volcanic-volcaniclastic sequence of andesitic tuff, lapillistone, agglomerate, andesitic and basaltic-andesitic lava flows. The volcaniclastic rocks are intercalated with lava flows and with rare pelagic limestone and shale beds. Although it is disrupted by several faults, the volcanic sequence can be traced from older to younger along the coast of &amp;#304;&amp;#287;neada. The sequence starts with andesitic volcaniclastic rocks and lava flows, and changes to basaltic-andesitic and then, again to andesitic rocks. The ocean floor alteration, which is found in all volcaniclastic and volcanic rock samples, and the intercalated pelagic limestones show that the rocks were deposited in deep submarine conditions in an intra-arc to fore-arc environment. Campanian (80.6 &amp;#177;1.5 Ma) U-Pb zircon ages, which are obtained from the andesitic tuffs at the base of the volcanic-volcaniclastic sequence, indicate a continued magmatism from Turonian to Campanian.&lt;/p&gt;

U–Pb age of the coesite-bearing eclogite from NW Borborema Province, NE Brazil: Implications for western Gondwana assembly

2015 ◽  
Vol 28 (3) ◽  
pp. 1183-1196 ◽  
Author(s):  
Ticiano José Saraiva dos Santos ◽  
Wagner da Silva Amaral ◽  
Matheus Fernando Ancelmi ◽  
Michele Zorzetti Pitarello ◽  
Reinhardt Adolfo Fuck ◽  
...  
Keyword(s):  
Borborema Province ◽  
Western Gondwana Assembly

scholarly journals C- and Sr-isotope stratigraphy of the São Caetano complex, Northeastern Brazil: a contribution to the study of the Meso-Neoproterozoic seawater geochemistry

2005 ◽  
Vol 77 (1) ◽  
pp. 137-155 ◽  
Author(s):  
Juan C. Silva ◽  
Alcides N. Sial ◽  
Valderez P. Ferreira ◽  
Márcio M. Pimentel
Keyword(s):  
Isotope Composition ◽  
Northeastern Brazil ◽  
Sr Isotope ◽  
Magmatic Arc ◽  
Tectonic Events ◽  
Borborema Province ◽  
Rodinia Supercontinent ◽  
Depositional Age ◽  
Continental Magmatic Arc ◽  
Stage 1

C-isotope and 87Sr/86Sr values for five carbonate successions from the São Caetano Complex, northeastern Brazil, were used to constrain their depositional age and to determine large variations in the C- and Sr-isotopic composition of seawater under the framework of global tectonic events. Three C-isotope stages were identified from base to top in a composed chemostratigraphic section: (1) stage in which delta13C values vary from +2 to +3.7‰ PDB and average 3‰ PDB, (2) stage with delta13C values displaying stronger oscillations (from -2‰ to +‰ PDB), and (3) stage with an isotopic plateau with values around +3.7‰ PDB. Constant 87Sr/86Sr values (~ 0.70600) characterize C-isotope stage 1, whereas slightly fluctuating values (from 0.70600 to 0.70700) characterize C-isotope stage 2. Finally, 87Sr/86Sr values averaging 0.70600 characterize C-isotope stage 3. The C- and Sr- chemostratigraphic pathways permit to state: (a) the C- and Sr-isotope secular curves registered primary fluctuations of the isotope composition of seawater during late Mesoproterozoic- early Neoproterozoic transition in the Borborema Province, and (b) onset of the Cariris Velhos/Greenville cycle, widespread oceanic rifting, continental magmatic arc formation and onset of the agglutination of Rodinia supercontinent, mostly controlled the C- and Sr-isotope composition of seawater during the C-isotope stages 1, 2 and 3.

Neoproterozoic magmatic arc systems of the central Ribeira belt, SE-Brazil, in the context of the West-Gondwana pre-collisional history: A review

2020 ◽  
Vol 103 ◽  
pp. 102710 ◽  
Author(s):  
Monica Heilbron ◽  
Claudio de Morisson Valeriano ◽  
Caroline Peixoto ◽  
Miguel Tupinambá ◽  
Franz Neubauer ◽  
...  
Keyword(s):  
The West ◽  
Magmatic Arc ◽  
West Gondwana ◽  
Se Brazil ◽  
Neoproterozoic Magmatic Arc
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