In the Himalayan region of Sikkim, well-developed inverted metamorphic sequence Main Central Thrust (MCT) zone is folded, thus exposing several transects through structure that reached similar grades at different times. In-situ LA-ICP-MS U–Th–Pb monazite ages, linked to pressure–temperature conditions via trace-element reaction fingerprints, allow key aspects evolution thrust be understood for first time. The ages show peak were earliest in structurally highest part sequence, Greater...

Geochemical and geochronological analyses provide quantitative evidence about the origin, development motion along ductile faults, where kinematic structures have been overprinted. The Main Central Thrust is a key structure in Himalaya that accommodated substantial amounts of India–Asia convergence. This juxtaposes two isotopically distinct rock packages across zone deformation. Structural analysis, whole-rock Nd isotopes, U–Pb zircon geochronology reveal hanging wall characterized by...

The metamorphic core of the Himalaya is composed Indian cratonic rocks with two distinct crustal affinities that are defined by radiogenic isotopic geochemistry and detrital zircon age spectra. One derived predominantly from Paleoproterozoic Archean interior either represented as metamorphosed sedimentary Lesser Himalayan Sequence (LHS) or slices distal margin. other Greater (GHS) whose provenance less clear has an enigmatic affinity. Here we present new Hf analyses LHS GHS samples spanning...

Quantitative constraints on the rates of tectonic processes underpin our understanding mechanisms that form mountains.In Sikkim Himalaya, late structural doming has revealed time-transgressive evidence metamorphism and thrusting permit calculation minimum rate movement a major ductile fault zone, Main Central Thrust (MCT), by novel methodology.U-Th-Pb monazite ages, compositions, metamorphic pressure-temperature determinations from rocks directly beneath MCT reveal samples ~50 km along...

Abstract The timing of slip on brittle faults in Earth’s upper crust is difficult to constrain, and direct radiometric dating fault-generated materials the most explicit approach. Here we make a comparison between K-Ar fault gouge clay (authigenic illite) U-Pb carbonate slickenfibers veins from same fault. We have dated generated Big Creek fault, northwest-striking, dextral strike-slip system Yukon Territory, Canadian Cordillera. Both methods yielded dates at ca. 73 Ma 60–57 Ma, representing...

Abstract The growth and dissolution behaviour of accessory phases (and especially those geochronological interest) in metamorphosed pelites depends on, among others, the bulk composition, prograde metamorphic evolution cooling path. Monazite zircon are arguably most commonly used geochronometers for dating felsic rocks, yet crystal mechanisms as a function rock pressure temperature still incompletely understood. Ages different zones monazite garnet‐bearing anatectic metapelite from Greater...

40Ar/39Ar dating of metamorphic rocks sometimes yields complicated datasets which are difficult to interpret in terms timescales the cycle. Single-grain fusion and step-heating data were obtained for sampled through a major thrust-sense shear zone (the Main Central Thrust) associated inverted Sikkim region eastern Himalaya. This transect provides natural laboratory explore factors influencing apparent ages similar lithologies at variety pressure temperature (P–T) conditions. The dataset...

The Bristol Channel Basin is a Mesozoic continental rift basin. basin an important analogue for offshore reservoirs. Relative cross-cutting relationships and correlation with adjacent sedimentary basins have previously been used to constrain the timing of development. In situ U–Pb carbonate geochronology has date calcite slickenfibre development in cores normal, thrust strike-slip faults East Quantoxhead Kilve region Somerset first time. Protracted north–south extension from c. 150 120 Ma...

Present-day along-strike heterogeneities within the Himalayan orogen are seen at many scales, from variations deep architecture of lithospheric mantle, to differences in geomorphologic surface processes. Here, we present an internally consistent petrochronologic dataset metamorphic core (HMC), order document and investigate causes its Oligocene–Miocene tectonic history. Laser ablation split-stream analysis was used date characterise geochemistry titanite 47 calc-silicate rocks across >2000...

Abstract Key metals important for the green energy transition concentrate during magmatic-hydrothermal processes. In porphyry deposits, epithermal mineralization can overprint earlier higher-temperature systems. It is not well understood whether occurs in a single evolving system or forms pulsed, episodic overprinting events. The timing and duration of fluid flow therefore remain key data gaps deposit models, but they are essential factors understanding metal (re)mobilization concentration...

The oldest record of a dortokid turtle (Testudines, Pan-Pleurodira) and the first occurrence group in UK is reported. This find corresponds to pan-pleurodiran country, only one from Mesozoic UK. new specimen, Lower Cretaceous (Barremian) Wessex Formation Isle Wight, comprises relatively complete shell with post cranial elements within calcite-filled vacuity. Micro CT scanning has revealed these tiny bones include cervical, dorsal caudal vertebrae, scapulae, pelvic girdle appendicular...

The Bristol Channel Basin (BCB) is a small continental rift basin that developed along the eastern margin of North-Atlantic during Mesozoic. Relatively minor inversion occurred Cenozoic. It has been extensively studied due to exceptional exposure faults both margins basin. Widespread calcite mineralisation overprinting fracture networks documents fluid partitioning these structures over time. However, temporal evolution deformation constrained solely from relative timing in field and through...

Faults act as sites for preferential failure in the continental crust when it is subjected to sequential tectonic events. To do so, they will typically have favourable orientation, geometry and/or be weaker than adjacent and are therefore prone slip. However, fluid flow that focussed along faults has a role modifying their mechanical strength, especially where different fluids, resulting mineralisation, partitioned particular structures. The East-Quantoxhead Fault (EQHF) Bristol Channel...

<p>Table S1 contains a summary of sample textures, grain size, associated minerals, and ages. Table S2 U-Pb data table. Supplemental material includes S1: Sample locations; S2: Analytical methods; S3: detailed descriptions data; S4: supplementary references for Figure 1. </p>

<p>Table S1 contains a summary of sample textures, grain size, associated minerals, and ages. Table S2 U-Pb data table. Supplemental material includes S1: Sample locations; S2: Analytical methods; S3: detailed descriptions data; S4: supplementary references for Figure 1. </p>

Monazite, (Ce,REE)PO4, is a common accessory mineral used to quantify the timing and duration of tectono-metamorphic processes in (poly)metamorphosed orogenic terranes. As monazite frequently yields spread ages, there can be ambiguity linking age domains specific metamorphic reactions and/or deformation events. This study aims to: (1) discerning effect on crystal structure; (2) understand how dynamic recrystallisation dissolution-precipitation mechanisms are recorded by distribution...

ABSTRACT Eclogite‐facies rocks provide important constraints on the behaviour of convergent plate boundaries and geometries tectonic reconstructions due to high ultrahigh pressure conditions at which they form. Many eclogite occurrences are documented near suture zone active collisional settings where interpreted mark approximate location former ocean basin subduction. Such observations influence interpretations for older eclogites within more deeply eroded and/or less well‐exposed terranes....