Apatite inclusions hosted by zircon offer a means to probe the magmatic history of granitic rocks and better constrain the volatile budgets of crystallising granitic melts. Building on recently ...developed F–Cl–OH partitioning models for apatite and coexisting melt, we outline an approach for estimating the melt concentrations of F and Cl from the composition of apatite inclusions in zircon, constrained by Ti-in-zircon crystallisation temperatures. The melts in equilibrium with apatite inclusions in zircon for the ‘I-type’ Jindabyne, Why Worry and Cobargo granitic suites of the Lachlan Orogen (eastern Australia), have Cl concentrations of 20–2880 ppm and F concentrations of 65–575 ppm. Variations in melt Cl and F concentrations between the granitic suites is attributed to differences in source compositions, specifically the relative contribution of F-rich turbiditic sediments and Cl-rich juvenile arc magmas. Within individual granitic suites, the calculated melt F and Cl concentrations decrease with magmatic differentiation and falling melt temperatures, and this appears to reflect the partitioning of Cl and F into biotite and hornblende, and into exsolving aqueous fluids. This study demonstrates that apatite-melt exchange coefficients for F, Cl and OH can be applied to apatite inclusions in zircon to quantify the F and Cl content of the melt, without additional context from the host rock samples.
•Summary of U–Pb geochronology of the Precambrian shield in Madagascar.•Nullification of the “Betsimisaraka Suture”.•The Greater Dharwar Craton and its southern Paleoproterozoic continent ...(SMIWH).•Review of Stenian–Tonian and Cryogenian- Ediacaran igneous rocks in Madagascar.•Ediacaran- Early Cambrian orogenic history of Madagascar and Gondwana.
Available U–Pb geochronology of the Precambrian shield of Madagascar is summarized and integrated into a synthesis of the region’s geological history. The shield is described in terms of six geodynamic domains, from northeast to southwest, the Bemarivo, Antongil–Masora, Antananarivo, Ikalamavony, Androyan–Anosyan, and Vohibory domains. Each domain is defined by distinctive suites of metaigneous rocks and metasedimentary groups, and a unique history of Archean (∼2.5Ga) and Proterozoic (∼1.0Ga, ∼0.80Ga, and ∼0.55Ga) reworking. Superimposed within and across these domains are scores of Neoproterozoic granitic stocks and batholiths as well as kilometer long zones of steeply dipping, highly strained rocks that record the effects of Gondwana’s amalgamation and shortening in latest Neoproterozoic time (0.560–0.520Ga).
The present-day shield of Madagascar is best viewed as part of the Greater Dharwar Craton, of Archean age, to which three exotic terranes were added in Proterozoic time. The domains in Madagascar representing the Greater Dharwar Craton include the Antongil–Masora domain, a fragment of the Western Dharwar of India, and the Neoarchean Antananarivo domain (with its Tsaratanana Complex) which is broadly analogous to the Eastern Dharwar of India. In its reconstructed position, the Greater Dharwar Craton consists of a central nucleus of Paleo-Mesoarchean age (>3.1Ga), the combined Western Dharwar and Antongil–Masora domain, flanked by mostly juvenile “granite–greenstone belts” of Neoarchean age (2.70–2.56Ga). The age of the accretionary event that formed this craton is approximately 2.5–2.45Ga. The three domains in Madagascar exotic to the Greater Dharwar Craton are the Androyan–Anosyan, Vohibory, and Bemarivo. The basement to the Androyan–Anosyan domain is a continental terrane of Paleoproterozoic age (2.0–1.78Ga) that was accreted to the southern margin (present-day direction) of the Greater Dharwar Craton in pre-Stratherian time (>1.6Ga), and rejuvenated at 1.03–0.93Ga with the creation of the Ikalamavony domain. The Vohibory domain, an oceanic terrane of Neoproterozoic age was accreted to the Androyan–Anosyan domain in Cryogenian time (∼0.63–0.60Ga). The Bemarivo domain of north Madagascar is a terrane of Cryogenian igneous rocks, with a cryptic Paleoproterozoic basement, that was accreted to the Greater Dharwar Craton in latest Ediacaran to earliest Cambrian time (0.53–0.51Ga).
El movimiento y la emoción son términos que guardan una profunda relación desde el punto de vista musical. El intérprete necesita del movimiento de su cuerpo para producir el sonido con su ...instrumento y además el gesto indica las intenciones que quiere transmitir el intérprete. Algunas piezas musicales tienen como finalidad transmitir un mensaje que influya en las emociones del oyente. La obra Suite of Movements (2017) para violoncelo solo de Castilla-Ávila se aleja de la suite tradicional y trata de expandir las posibilidades sonoras del instrumento. La obra reflexiona en torno a la relación del movimiento y la música a través de la improvisación, el intercambio de técnicas instrumentales y la búsqueda de nuevos recursos sonoros.
•Granitic Intrusions in the Brusque Group were emplaced between 615 and 585 Ma.•Relative field stratigraphy of the different suites is not reflected in U-Pb ages.•Inherited zircons and Lu-Hf isotopy ...indicate predominant crustal magma sources.•Intrusions represent progressive emplacement during regional heating.•Granite variety reflects local sources & emplacement in contrasting crustal levels.
The central Domain of the Neoproterozoic Dom Feliciano Belt in the Brazilian state of Santa Catarina is mainly composed of a metavolcano-sedimentary sequence, the Brusque Group, and its crystalline basement, such as the Camboriú Complex. This association was intruded in its late-deformational stage by voluminous granitic magmatism, related to the metamorphic climax of the area. The intrusions share a distinct crustal affinity and are divided into three suites, from oldest to youngest, as indicated by field criteria: São João Batista, Valsungana and Nova Trento. We present seven new LA-ICP-MS and two SHRIMP U-Pb zircon ages, coupled with in-situ analysis of Hf isotopes, and use them to discuss the magmatic sources and evolution of the intrusions, and propose an evolutionary model for this plutonic association. Intrusion mostly took place at 615–585 Ma, but the field stratigraphy is not necessarily reflected by U-Pb ages, which establish considerable overlaps between intrusions from different suites. Inherited zircon crystals are common, and reflect a long geological history that matches the geochronological record of the Brusque Group and the Camboriú Complex. Hf ratios are remarkably widespread, but strengthen the characteristic crustal signature of the magmatism, and partially overlap with whole-rock isotopic data for the same rocks. We propose that the intrusions were caused by a regional heating event within the central domain of the Dom Feliciano Belt in Santa Catarina, with limited direct mantellic contribution and more significant indirect thermal contribution through the voluminous magmatism of the recently juxtaposed Florianópolis Batholith. This triggered large-scale partial melting of the local continental crustal and formed the studied granites. The long-lasting magmatic event promoted the protracted generation and emplacement of numerous distinct intrusions synchronically, leading to contrasts between the field and U-Pb stratigraphy. The suites’ varied geochemical and isotopic characteristics probably reflect a combination of the heterogeneities of their source rocks with the impact of different magmatic processes during granitogenesis and emplacement. While the Valsungana and Nova Trento suites were probably generated within a deeper crustal level and underwent some degree of magmatic interaction, the peraluminous São João Batista Suite has an upper-crust signature that indicates the assimilation of metasedimentary rocks.
Magmatism during the maturation phase of Archean greenstone belts produced voluminous tonalite-trondhjemite-granodiorite (TTG) suites, as well as a lesser amount of tonalite-trondhjemite-diorite ...(TTD) suites. Such TTD suites have recently been recognized in the Archean Abitibi greenstone belt, on the southern flank of the Superior Craton, Canada, but their source(s), differentiation processes, and depths of emplacement remain poorly constrained. The Neoarchean Eau Jaune Complex lies in the northeastern corner of the Abitibi greenstone belt and represents one of the most voluminous tonalite-dominated and diorite-bearing intrusive suites of the Chibougamau region. This TTD suite comprises six intrusive phases with distinct petrology and chemistry. All units were emplaced as laccolith-like intrusions injected along discontinuities within the volcanic succession at ca. 2724 Ma (U-Pb zircon dating), during the synvolcanic interval (i.e., construction and maturation phase), at a depth of approximately 7-8 km. The most heavy rare-earth element (HREE)-depleted phases (granodiorite, tonalite, and trondhjemite) correspond to magmas that fractionated amphibole and were likely produced by partial melting of a garnet- and titanate-bearing amphibolite, akin to TTG magmas. The least HREE-depleted phases are dioritic in composition and correspond to mantle-derived magmas that may have interacted with TTG melts. This indicates interaction between coeval mantle-derived and crustal melts during the maturation phase of the Abitibi greenstone belt. Models formulated to address the geodynamic evolution of greenstone belts must account for the coeval production of basalt-derived (TTG suites) and mantle-derived (tholeiitic magmatism) melts occasionally interacting to form TTD suites.
•The Rudall Province is the sole Proterozoic exposure between the North and West Australian Cratons.•We present new zircon U-Pb, Lu-Hf and O isotope date from the Rudall Province.•We favour a ...Mesoproterozoic assembly of the North and West Australian Cratons.
The Proterozoic assembly of Australia involved the convergence of three main Archean cratonic entities: the North, West and South Australian Cratons, and is recorded in the Proterozoic orogenic belts surrounding these continental nuclei. The Rudall Province of northern Western Australia is the sole exposure of a Paleo- to Mesoproterozoic orogen lying between the North and West Australian Cratons, and may record the effects of their amalgamation. We present new zircon O, U–Pb and Lu–Hf isotope data from magmatic rocks across the Rudall Province, to which we add existing isotope data to yield a crustal evolution overview. Hf evolution trends for the ca. 1804–1762 Ma Kalkan Supersuite, the ca. 1589–1549 Ma Krackatinny Supersuite and the ca. 1310–1286 Ma Camel Suite, indicate a significant input of Archean East Pilbara Basement material, albeit as a mix with more juvenile material, including a possible ca. 1900 Ma component. Zircon δ18O data suggest a contribution from supracrustal material into the magmatic source of the Kalkan Supersuite, which may have been emplaced in an extensional setting. In contrast, the Krackatinny Supersuite and Camel Suite have mantle-like δ18O which may reflect partial melting of deeper Archean sources. Geochemical data for the Krackatinny Supersuite shows geochemical trends implying that melting of thickened mafic crust progressed from deeper to shallower levels, possibly in a rift setting. Camel Suite K-rich leucogranites may also have been emplaced in an extensional setting towards the end of high-P metamorphism. All terranes of the Rudall Province are para-autochthonous with respect to the Pilbara Craton, with no requirement for arc-related magmatism. We outline two potential scenarios for the Paleo- to Mesoproterozoic geodynamic evolution of the Rudall Province: an early cratonic amalgamation between the West and North Australian Cratons ca. 1680 Ma followed by Mesoproterozoic intraplate events; or a later assembly ca. 1377–1275 Ma. We lean towards this later amalgamation scenario.
In this paper we present U–Pb age data of detrital and magmatic zircons from sedimentary and volcanic rocks in the Zhangguangcailing Group (ZG), NE China, to constrain the tectonic evolution of the ...region as a whole. The ZG consists of slightly metamorphosed volcanic and sedimentary rocks, and from bottom to top is divided into the Zhenggou, Hongguang, and Xinxing suites. Zircons from three schists in the Zhenggou suite give 12 main groups of age populations (from 226 to 861Ma), whereas zircons from a basaltic andesite give a Late Triassic age (211±2Ma). In the Hongguang suite, zircons from two schists and a greywacke give 6 main groups, 5 main groups, and 3 main groups of age populations (from 262 to 916Ma), respectively, whereas zircons from a gabbro–diorite and two volcanic rocks give ages of 259, 219, and 317Ma, respectively. Zircons from a schist in the Xinxing suite give 12 main groups of age populations (from 284 to 1837Ma). These results, together with the field relationships of the rocks, indicate (1) that the sedimentary and volcanic rocks of the ZG have diverse ages (from Early Paleozoic to Early Mesozoic), (2) that the rocks do not lie in a logical stratigraphic sequence, and (3) that the rocks represent a tectonic mélange. Based on the youngest age (211Ma) for volcanic rocks within the ZG, and the age of deformation (174–184Ma) of the Heilongjiang Complex, we propose that the tectonic mélange formed during the Late Triassic–Early Jurassic. Furthermore, the occurrence of detrital zircons with ages of 0.8–0.9, 1.8, and 2.4–2.5Ga implies the existence of Neoproterozoic magmatism and the remnants of a Precambrian basement in the Songnen–Zhangguangcai Range Massif, NE China.
► U–Pb ages of detrital and magmatic zircons from the Zhangguangcailing Group are presented. ► The formation ages of these rocks range from Early Paleozoic to Early Mesozoic. ► The so-called Zhangguangcailing Group is actually a tectonic mélange. ► The formation of this mélange took place during the Early–Middle Jurassic.
Real-world optimization problems have been comparatively difficult to solve due to the complex nature of the objective function with a substantial number of constraints. To deal with such problems, ...several metaheuristics as well as constraint handling approaches have been suggested. To validate the effectiveness and strength, performance of a newly designed approach should be benchmarked by using some complex real-world problems, instead of only the toy problems with synthetic objective functions, mostly arising from the area of numerical analysis. A list of standard real-life problems appears to be the need of the time for benchmarking new algorithms in an efficient and unbiased manner. In this study, a set of 57 real-world Constrained Optimization Problems (COPs) are described and presented as a benchmark suite to validate the COPs. These problems are shown to capture a wide range of difficulties and challenges that arise from the real life optimization scenarios. Three state-of-the-art constrained optimization methods are exhaustively tested on these problems to analyze their hardness. The experimental outcomes reveal that the selected problems are indeed challenging to these algorithms, which have been shown to solve many synthetic benchmark problems easily.
Silurian plutonic suites in the Newfoundland Appalachians include abundant gabbro, monzogabbro and granite to granodiorite and lesser quartz diorite and tonalite. Most are medium- to high-K, but ...included are some low-K and shoshonitic mafic compositions. Felsic rocks are of both alkaline (A-type or within-plate granite (WPG)) and calc-alkaline volcanic arc granite (VAG) affinity. Mafic rocks include both arc-like (Nb/Th
<
3) calc-alkaline and non-arc-like (Nb/Th
>
3) transitional calc-alkaline basalt to continental tholeiitic affinity compositions.
ε
Nd(
T) values range from −
9.6 to +
5.4 and
δ
18O (VSMOW) values range from +
3.1 to +
13.2‰.
A rapid progression from exclusively arc-type to non-arc-like mafic and then contemporaneous WPG plus VAG magmatism has been documented using precise U–Pb zircon dating. Earlier arc-like plutonism indicates subduction, while asthenosphere-derived mafic magmas support slab break-off, due to subduction of a young, warm back-arc basin. Contemporaneous mafic magmas with arc and non-arc geochemical signatures may reflect tapping of asthenospheric and subcontinental lithospheric mantle (SCLM) sources and/or contamination of asthenosphere-derived magmas by SCLM or crust.
The brevity (<
5 Ma) of the mafic magmatic pulse agrees with the transient nature of magmatism associated with slab break-off. The subsequent ca. 1 to 2 m.y. period of voluminous WPG and VAG plutonism likely reflects mafic magma-driven partial melting of both SCLM and crustal sources, respectively. Continuation of VAG-like magmatism for an additional 2 to 5 m.y. may reflect lower solidus temperatures of crustal materials, enabling anatexis to continue after mantle melting ceased. East to west spatial variation of
ε
Nd and (La/Yb)
CN in Silurian plutons suggests a transition from shallow melting of juvenile sources proximal to the collision zone to deeper melting of old source materials in the garnet-stability field further inboard.
Previous work has demonstrated that geochemical discriminaton of post-collisional granitoid magmatism (PCGM) is difficult in the absence of other constraints. Our example should contribute to the understanding and identification of PCGM if it can be employed as a ‘fingerprint’ for slab break-off-related PCGM within the Paleozoic geological record.
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