ABSTRACT Massif-type anorthosite complexes constitute a distinct component of the Proterozoic Eas... more ABSTRACT Massif-type anorthosite complexes constitute a distinct component of the Proterozoic Eastern Ghats Province in India. They intruded the poly-deformed and poly-metamorphic granulite facies terrane near its western and northern tectonic contacts with the Archaean Bastar and Singhbhum cratons, respectively. Following their emplacement, the complexes were variously affected by high-grade metamorphism and deformation. The Turkel Anorthosite Complex comprises an anorthosite-leuconorite diapir encircled by voluminous crust-derived quartz-monzonite intrusions hosted within an expansive batholithic complex of megacrystic K-feldspar granite and remnants of an older gneissic unit. This contribution evaluates the pressure-temperature history of the anorthosite complex based on textural relations, paragenetic characteristics, and mineral chemistry, and provides for the first time, constraints on the timing of emplacement and subsequent metamorphism of the rocks through in-situ U-Pb dating of zircon from several members of the suite. Emplacement of the Turkel Anorthosite Complex occurred after the fabric-defining late-Mesoproterozoic deformation (D1-D3) and high-grade metamorphism of the country rocks and was shortly preceded by the surrounding expansive intrusion of the megacrystic K-feldspar granite. The leuconorite-anorthosite suite crystallized at 980 ± 8 Ma while the other components including the monzonite, quartz monzonite, and ferrodiorite were emplaced later between 956 ± 6 and 945 ± 5Ma. The post-intrusion evolution of the complex is characterized by partial re-equilibration of the igneous parageneses and textures during an initial episode of cooling and decompression from the magmatic crystallization stage (1100-950 °C, 12-7 kbar) towards the ambient thermobaric regime, and following prolonged slow cooling by an episode of renewed compressional deformation (late-D3; ca. 750 °C, 6.5-7.0 kbar) that caused the thorough high-grade recrystallization of the rocks and produced the monophase planar fabric of the complex. U-Pb spot ages from metamorphic domains of zircon grains constrain the age of this metamorphism to 901-879 Ma. The complex was moderately affected by the late Neoproterozoic to early Palaeozoic Pan-African tectonothermal event which led to internal tectonic segmentation and westward thrusting of the Khariar and Rampur domains of the northern Eastern Ghats Province onto the Bastar craton.
Peptidic supramolecular hydrogels and aggregates are a current hot topic because of their multipl... more Peptidic supramolecular hydrogels and aggregates are a current hot topic because of their multiple properties and applications. In particular, the enhancement of the catalytic properties due to the aggregation has been studied in detail in our group leading to remarkable results in this field. 1 Furthermore, self-replicating systems are of paramount relevance for the studies of the origin of life. 2 In this kind of systems the reaction product act as an specific catalyst for its own synthesis by recognizing and promoting coupling of reactants due to supramolecular interactions. Considering this two relevant topics we aim to develop a new system which combines both properties. The main goal of the project is to create a catalytic self-replicating system that is able not only to catalyze its own formation but also to act as a self-assembled catalyst for an external chemical reaction. Here preliminary results will be presented. Figure 1: Schematic representation of a self-replicating a...
Naphthalenediimide appended peptide based self-assembly was studied. Interestingly, an aggregatio... more Naphthalenediimide appended peptide based self-assembly was studied. Interestingly, an aggregation induced drastic change in the fluorescence property and gel formation were observed depending on the solvent composition (chloroform : methylcyclohexane) at a fixed concentration of 1.6 mM at room temperature.
The pH-induced self-assembly of three synthetic tripeptides in water medium is used to immobilize... more The pH-induced self-assembly of three synthetic tripeptides in water medium is used to immobilize luminescent CdS nanoparticles. These peptides form a nanofibrillar network structure upon gelation in aqueous medium at basic pH values (pH 11.0–13.0), and the fabrication of CdS nanoparticles on the gel nanofiber confers the luminescent property to these gels. Atomic force microscopy, field-emission scanning electron microscopy, and high-resolution transmission electron microscopy clearly reveal the presence of CdS nanoparticles in a well-defined array on the gel nanofibers. This is a convenient way to make organic nanofiber–inorganic nanoparticle hybrid nanocomposite systems. The size of the CdS nanoparticles remains almost same before and after deposition on the gel nanofiber. Photoluminescence (PL) measurement of the CdS nanoparticles upon deposition on the gel nanofibers shows a significant blue shift in the emission spectrum of the nanoparticles, and there is a considerable change in the PL gap energy of the CdS nanoparticles after immobilization on different gel nanofibrils. This finding suggests that the optoelectronic properties of CdS nanoparticles can be tuned upon deposition on gel nanofibers without changing the size of the nanoparticles.
ABSTRACT Massif-type anorthosite complexes constitute a distinct component of the Proterozoic Eas... more ABSTRACT Massif-type anorthosite complexes constitute a distinct component of the Proterozoic Eastern Ghats Province in India. They intruded the poly-deformed and poly-metamorphic granulite facies terrane near its western and northern tectonic contacts with the Archaean Bastar and Singhbhum cratons, respectively. Following their emplacement, the complexes were variously affected by high-grade metamorphism and deformation. The Turkel Anorthosite Complex comprises an anorthosite-leuconorite diapir encircled by voluminous crust-derived quartz-monzonite intrusions hosted within an expansive batholithic complex of megacrystic K-feldspar granite and remnants of an older gneissic unit. This contribution evaluates the pressure-temperature history of the anorthosite complex based on textural relations, paragenetic characteristics, and mineral chemistry, and provides for the first time, constraints on the timing of emplacement and subsequent metamorphism of the rocks through in-situ U-Pb dating of zircon from several members of the suite. Emplacement of the Turkel Anorthosite Complex occurred after the fabric-defining late-Mesoproterozoic deformation (D1-D3) and high-grade metamorphism of the country rocks and was shortly preceded by the surrounding expansive intrusion of the megacrystic K-feldspar granite. The leuconorite-anorthosite suite crystallized at 980 ± 8 Ma while the other components including the monzonite, quartz monzonite, and ferrodiorite were emplaced later between 956 ± 6 and 945 ± 5Ma. The post-intrusion evolution of the complex is characterized by partial re-equilibration of the igneous parageneses and textures during an initial episode of cooling and decompression from the magmatic crystallization stage (1100-950 °C, 12-7 kbar) towards the ambient thermobaric regime, and following prolonged slow cooling by an episode of renewed compressional deformation (late-D3; ca. 750 °C, 6.5-7.0 kbar) that caused the thorough high-grade recrystallization of the rocks and produced the monophase planar fabric of the complex. U-Pb spot ages from metamorphic domains of zircon grains constrain the age of this metamorphism to 901-879 Ma. The complex was moderately affected by the late Neoproterozoic to early Palaeozoic Pan-African tectonothermal event which led to internal tectonic segmentation and westward thrusting of the Khariar and Rampur domains of the northern Eastern Ghats Province onto the Bastar craton.
Peptidic supramolecular hydrogels and aggregates are a current hot topic because of their multipl... more Peptidic supramolecular hydrogels and aggregates are a current hot topic because of their multiple properties and applications. In particular, the enhancement of the catalytic properties due to the aggregation has been studied in detail in our group leading to remarkable results in this field. 1 Furthermore, self-replicating systems are of paramount relevance for the studies of the origin of life. 2 In this kind of systems the reaction product act as an specific catalyst for its own synthesis by recognizing and promoting coupling of reactants due to supramolecular interactions. Considering this two relevant topics we aim to develop a new system which combines both properties. The main goal of the project is to create a catalytic self-replicating system that is able not only to catalyze its own formation but also to act as a self-assembled catalyst for an external chemical reaction. Here preliminary results will be presented. Figure 1: Schematic representation of a self-replicating a...
Naphthalenediimide appended peptide based self-assembly was studied. Interestingly, an aggregatio... more Naphthalenediimide appended peptide based self-assembly was studied. Interestingly, an aggregation induced drastic change in the fluorescence property and gel formation were observed depending on the solvent composition (chloroform : methylcyclohexane) at a fixed concentration of 1.6 mM at room temperature.
The pH-induced self-assembly of three synthetic tripeptides in water medium is used to immobilize... more The pH-induced self-assembly of three synthetic tripeptides in water medium is used to immobilize luminescent CdS nanoparticles. These peptides form a nanofibrillar network structure upon gelation in aqueous medium at basic pH values (pH 11.0–13.0), and the fabrication of CdS nanoparticles on the gel nanofiber confers the luminescent property to these gels. Atomic force microscopy, field-emission scanning electron microscopy, and high-resolution transmission electron microscopy clearly reveal the presence of CdS nanoparticles in a well-defined array on the gel nanofibers. This is a convenient way to make organic nanofiber–inorganic nanoparticle hybrid nanocomposite systems. The size of the CdS nanoparticles remains almost same before and after deposition on the gel nanofiber. Photoluminescence (PL) measurement of the CdS nanoparticles upon deposition on the gel nanofibers shows a significant blue shift in the emission spectrum of the nanoparticles, and there is a considerable change in the PL gap energy of the CdS nanoparticles after immobilization on different gel nanofibrils. This finding suggests that the optoelectronic properties of CdS nanoparticles can be tuned upon deposition on gel nanofibers without changing the size of the nanoparticles.
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