Petrographic and isotopic characteristics of hornblende-bearing cumulates and pyroxene granulite xenoliths from Kampu volcano, Oga peninsula, Northeast Japan Arc: High-pressure crystallization of hornblende and metasomatism of lower crustal material

Some (ultra)high-pressure metamorphic rocks that formed during continental collision preserve relict minerals, indicating a two-stage evolution: first, subduction to mantle depths and exhumation to the lower-crustal level (with simultaneous cooling), followed by intensive heating that can be characterized by a β-shaped pressure–temperature–time (P–T–t) path. Based on a two-dimensional (2D) coupled petrological–thermomechanical tectono-magmatic numerical model, we propose a possible sequence of tectonic stages that could lead to these overprinting metamorphic events along an orogenic β-shaped P–T–t path: the subduction and exhumation of continental crust, followed by slab retreat that leads to extension and subsequent asthenospheric upwelling. During the last stage, the exhumed crustal material at the crust–mantle boundary undergoes heating from the underlying hot asthenospheric mantle. This slab rollback scenario is further compared numerically with the classical continental collision scenario associated with slab breakoff, which is often used to explain the late heating impulse in the collisional orogens. The mantle upwelling occurring in the experiments with slab breakoff, which is responsible for the heating of the exhumed crustal material, is not related to the slab breakoff but can be caused either by slab bending before slab breakoff or by post-breakoff exhumation of the subducted crust. Our numerical modeling predictions align well with a variety of orogenic P–T–t paths that have been reported from many Phanerozoic collisional orogens, such as the Variscan Bohemian Massif, the Triassic Dabie Shan, the Cenozoic Northwest Himalaya, and some metamorphic complexes in the Alps.

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Up the down escalator: the exhumation of (ultra)-high pressure terranes during on-going subduction

Solid Earth Discussions ◽

10.5194/sed-4-745-2012 ◽

2012 ◽

Vol 4 (1) ◽

pp. 745-781 ◽

Cited By ~ 5

Author(s):

C. J. Warren

Keyword(s):

High Pressure ◽

Subduction Zone ◽

Continental Crust ◽

Subduction Zones ◽

Crustal Material ◽

Time And Space ◽

Ultra High Pressure ◽

Tectonic Environment ◽

Tectonic Style ◽

Weak Material

Abstract. The exhumation of high and ultra-high pressure rocks is ubiquitous in Phanerozoic orogens created during continental collisions, and is common in many ocean-ocean and ocean-continent subduction zone environments. Three different tectonic environments have previously been reported, which exhume deeply buried material by different mechanisms and at different rates. However it is becoming increasingly clear that no single mechanism dominates in any particular tectonic environment, and the mechanism may change in time and space within the same subduction zone. In order for buoyant continental crust to subduct, it must remain attached to a stronger and denser substrate, but in order to exhume, it must detach (and therefore at least locally weaken) and be initially buoyant. Denser oceanic crust subducts more readily than more buoyant continental crust but exhumation must be assisted by entrainment within more buoyant and weak material such as serpentinite or driven by the exhumation of structurally lower continental crustal material. Weakening mechanisms responsible for the detachment of crust at depth include strain, hydration, melting, grain size reduction and the development of foliation. These may act locally or may act on the bulk of the subducted material. Metamorphic reactions, metastability and the composition of the subducted crust all affect buoyancy and overall strength. Subduction zones change in style both in time and space, and exhumation mechanisms change to reflect the tectonic style and overall force regime within the subduction zone. Exhumation events may be transient and occur only once in a particular subduction zone or orogen, or may be more continuous or occur multiple times.

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Preparation of silymarin nanocrystals using a novel high pressure crystallization technique and evaluation of its dissolution and absorption properties

Asian Journal of Pharmaceutical Sciences ◽

10.1016/j.ajps.2015.11.031 ◽

2016 ◽

Vol 11 (1) ◽

pp. 211-212 ◽

Cited By ~ 2

Author(s):

Risako Onodera ◽

Tomohiro Hayashi ◽

Tatsuo Nakamura ◽

Kaori Aibe ◽

Kohei Tahara ◽

...

Keyword(s):

High Pressure ◽

Absorption Properties ◽

Pressure Crystallization

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High-Pressure Crystallization and Structural Transformations in Compressed R,S-Ibuprofen

Crystal Growth & Design ◽

10.1021/cg5018888 ◽

2015 ◽

Vol 15 (3) ◽

pp. 1512-1517 ◽

Cited By ~ 15

Author(s):

Kinga Ostrowska ◽

Magdalena Kropidłowska ◽

Andrzej Katrusiak

Keyword(s):

High Pressure ◽

Structural Transformations ◽

Pressure Crystallization

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Under Pressure: High-Pressure Metamorphism in the Alps

Elements ◽

10.2138/gselements.17.1.17 ◽

2021 ◽

Vol 17 (1) ◽

pp. 17-22 ◽

Cited By ~ 1

Author(s):

Lucie Tajčmanová ◽

Paola Manzotti ◽

Matteo Alvaro

Keyword(s):

High Pressure ◽

Structural Data ◽

Metamorphic Rocks ◽

Lithostatic Pressure ◽

Mineral Inclusion ◽

Crustal Material ◽

Local Pressure ◽

Ultra High Pressure ◽

Mechanical Models ◽

The Alps

The mechanisms attending the burial of crustal material and its exhumation before and during the Alpine orogeny are controversial. New mechanical models propose local pressure perturbations deviating from lithostatic pressure as a possible mechanism for creating (ultra-)high-pressure rocks in the Alps. These models challenge the assumption that metamorphic pressure can be used as a measure of depth, in this case implying deep subduction of metamorphic rocks beneath the Alpine orogen. We summarize petro-logical, geochronological and structural data to assess two fundamentally distinct mechanisms of forming (ultra-)high-pressure rocks: deep subduction; or anomalous, non-lithostatic pressure variation. Furthermore, we explore mineral-inclusion barometry to assess the relationship between pressure and depth in metamorphic rocks.

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High-Pressure Crystallization of Binary Unsaturated Fatty Acids in Cylindrical Cell

Journal of Crystal Growth ◽

10.1016/j.jcrysgro.2021.126380 ◽

2021 ◽

pp. 126380

Author(s):

Kouji Maeda ◽

Yosuke Naito ◽

Hidetoshi Kuramochi ◽

Koji Arafun ◽

Kazuhiro Itoh ◽

...

Keyword(s):

Fatty Acids ◽

High Pressure ◽

Unsaturated Fatty Acids ◽

Cylindrical Cell ◽

Pressure Crystallization

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Geology, Geochronology and Geochemistry of Weilasituo Sn-Polymetallic Deposit in Inner Mongolia, China

Minerals ◽

10.3390/min9020104 ◽

2019 ◽

Vol 9 (2) ◽

pp. 104 ◽

Cited By ~ 5

Author(s):

Fan Yang ◽

Jinggui Sun ◽

Yan Wang ◽

Junyu Fu ◽

Fuchao Na ◽

...

Keyword(s):

Pacific Ocean ◽

Lower Crust ◽

Structural Evolution ◽

Magma Source ◽

Crustal Material ◽

Quartz Porphyry ◽

Polymetallic Deposit ◽

High Concentrations ◽

Great Xing’An Range ◽

Lower Crustal

The recently discovered Weilasituo Sn-polymetallic deposit in the Great Xing’an Range is an ultralarge porphyry-type deposit. The mineralization is closely associated with an Early Cretaceous quartz porphyry. Analysis of quartz porphyry samples, including zircon U-Pb dating and Hf isotopies, geochemical and molybdenite Re-Os isotopic testing, reveals a zircon U-Pb age of 138.6 ± 1.1 Ma and a molybdenite Re-Os isotopic age of 135 ± 7 Ma, suggesting the concurrence of the petrogenetic and metallogenic processes. The quartz porphyry has high concentrations of SiO2 (71.57 wt %–78.60 wt %), Al2O3 (12.69 wt %–16.32 wt %), and K2O + Na2O (8.85 wt %–10.44 wt %) and A/CNK ratios from 0.94–1.21, is mainly peraluminous, high-K calc-alkaline I-type granite and is relatively rich in LILEs (large ion lithophile elements, e.g., Th, Rb, U and K) and HFSEs (high field strength elements, e.g., Hf and Zr) and relatively poor in Sr, Ba, P, Ti and Nb. The zircon εHf(t) values range from 1.90 to 6.90, indicating that the magma source materials were mainly derived from the juvenile lower crust and experienced mixing with mantle materials. Given the regional structural evolution history, we conclude that the ore-forming magma originated from lower crust that had thickened and delaminated is the result of the subduction of the Paleo–Pacific Ocean. Following delamination, the lower crustal material entered the underlying mantle, where it was partially melted and reacted with mantle during ascent. The deposit formed at a time of transition from post-orogenic compression to extension following the subduction of the Paleo–Pacific Ocean.

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