Mineral Chemistry and Pressure–Temperature Evolution of Two Contrasting High-pressure–Low-temperature Belts in the Chonos Archipelago, Southern Chile

Las Ollas complex (LOC) is a subduction complex spatially associated with the early Cretaceous Zihuatanejo-Huetamo subterrane (Guerrero terrane) in southern Mexico. LOC tectonic mélanges compose of a stack of east-dipping, west-vergent tectonic sheets containing blocks of metabasalt, metadolerite, metagabbro, ultramafics, volcaniclastics, quartz-rich sandstone, and chert enveloped in a highly sheared clastic or serpentinitic matrix. Most igneous and igneous-derived metamorphic blocks show geochemical and isotopic features typical of island-arc tholeiitic suites: (i) low TiO2 (0.13 to 0.91%) and Zr (5 to 57 ppm) contents; (ii) high (LFSE/HFSE)N ratios; low LaN/YbN (0.5 to 4) values; and, high εNd(T) (+7.9 to +8.0) ratios. Petrographical and mineral chemistry evidence indicates that blocks underwent early recrystallization under high pressure and low temperature (HP-LT), blueschist facies conditions during subduction. Typical assemblages include blue (sodic through calco-sodic to Na-rich calcic) amphibole + lawsonite ± tremolite ± Mg-chlorite ± white mica ± albite ± quartz. Phase relations and chlorite thermometry suggest temperatures of about 200°-330o C and pressures of 5-7 kbar. It is proposed that sedimentary blocks were generated by in situ remobilization and mixing, whereas igneous blocks most probably derived from the chemically and isotopically identical Zihuatanejo island-arc suite. Our data suggest that LOC represents part of a subduction complex formed by eastward-directed subduction related with the evolution of the early Cretaceous Zihuatanejo island arc.

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High-Pressure - Low-temperature evolution in the Indus-Tsangpo Suture along the Kohistan Arc (Kaghan Valley, NE Pakistan)

Episodes ◽

10.18814/epiiugs/2013/v36i2/002 ◽

2013 ◽

Vol 36 (2) ◽

pp. 87-93 ◽

Cited By ~ 10

Author(s):

Roland Oberhänsli

Keyword(s):

High Pressure ◽

Low Temperature ◽

Temperature Evolution

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Interaction of Oxidizing and Reductive Components in CO2 Streams with Transport Pipeline Steel X70 at High Pressure and Low Temperature

SSRN Electronic Journal ◽

10.2139/ssrn.3365756 ◽

2019 ◽

Author(s):

Andreas Kratzig ◽

Dirk Bettge ◽

Hoa Le Quynh ◽

Ralph Bäßler ◽

Axel Kranzmann

Keyword(s):

High Pressure ◽

Low Temperature ◽

Pipeline Steel

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Low-Temperature Hydrogenation of Mg-Ni-Nb2O5 Alloy Processed by High-Pressure Torsion

Journal of Alloys and Compounds ◽

10.1016/j.jallcom.2021.160309 ◽

2021 ◽

pp. 160309

Author(s):

M. Osorio-García ◽

K. Suárez-Alcántara ◽

Y. Todaka ◽

A. Tejeda-Ochoa ◽

M. Herrera Ramírez ◽

...

Keyword(s):

High Pressure ◽

Low Temperature ◽

High Pressure Torsion

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Study of high-pressure air jet controlled compression ignition with compound thermodynamic cycle for combustion and emission formation process

International Journal of Engine Research ◽

10.1177/1468087420969337 ◽

2020 ◽

pp. 146808742096933

Author(s):

Xiangyu Meng ◽

Sicheng Liu ◽

Jingchen Cui ◽

Jiangping Tian ◽

Wuqiang Long ◽

...

Keyword(s):

High Pressure ◽

High Temperature ◽

Low Temperature ◽

Formation Process ◽

Combustion Process ◽

Thermodynamic Cycle ◽

Compression Ignition ◽

Temperature Reaction ◽

Air Jet ◽

High Temperature Reaction

A novel method called high-pressure air (HPA) jet controlled compression ignition (JCCI) based on the compound thermodynamic cycle was investigated in this work. The combustion process of premixed mixture can be controlled flexibly by the high-pressure air jet compression, and it characterizes the intensified low-temperature reaction and two-stage high-temperature reaction. The three-dimensional (3D) computational fluid dynamics (CFD) numerical simulation was employed to study the emission formation process and mechanism, and the effects of high-pressure air jet temperature and duration on emissions were also investigated. The simulation results showed that the NOx formation is mainly affected by the first-stage high-temperature reaction due to the higher reaction temperature. Overall, this combustion mode can obtain ultra-low NOx emission. The second-stage high-temperature reaction plays an important role in the CO and THC formation caused by the mixing effect of the high-pressure air and original in-cylinder mixture. The increasing air jet temperature leads to a larger high-temperature in-cylinder region and more fuel in the first-stage reaction, and therefore resulting in higher NOx emission. However, the increasing air jet temperature can significantly reduce the CO and THC emissions. For the air jet duration comparisons, both too short and too long air jet durations could induce higher NOx emission. A higher air jet duration would result in higher CO emission due to the more high-pressure air jet with relatively low temperature.

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