scholarly journals Water transfer to the deep mantle through hydrous, Al-rich silicates in subduction zones

Geology ◽  
2021 ◽  
Author(s):  
Jörg Hermann ◽  
Shayne Lakey
Keyword(s):  
Deep Water ◽  
Subduction Zones ◽  
Water Cycle ◽  
Temperature Stability ◽  
Water Transfer ◽  
Critical Conditions ◽  
Water Recycling ◽  
Secular Equilibrium ◽  
Order Problem ◽  
Deep Mantle

Constraining deep-water recycling along subduction zones is a first-order problem to understand how Earth has maintained a hydrosphere over billions of years that created conditions for a habitable planet. The pressure-temperature stability of hydrous phases in conjunction with slab geotherms determines how much H2O leaves the slab or is transported to the deep mantle. Chlorite-rich, metasomatic rocks that form at the slab-mantle interface at 50–100 km depth represent an unaccounted, H2O-rich reservoir in subduction processes. Through a series of high-pressure experiments, we investigated the fate of such chlorite-rich rocks at the most critical conditions for subduction water recycling (5–6.2 GPa, 620–800 °C) using two different natural ultramafic compositions. Up to 5.7 GPa, 740 °C, chlorite breaks down to an anhydrous peridotite assemblage, and H2O is released. However, at higher pressures and lower temperatures, a hydrous Al-rich silicate (11.5 Å phase) is an important carrier to enable water transfer to the deep mantle for cold subduction zones. Based on the new phase diagrams, it is suggested that the deep-water cycle might not be in secular equilibrium.

scholarly journals Supplemental Material: Water transfer to the deep mantle through hydrous, Al-rich silicates in subduction zones

2021 ◽  
Author(s):  
Joerg Hermann ◽  
Shayne Lakey
Keyword(s):  
Analytical Methods ◽  
Subduction Zones ◽  
Water Transfer ◽  
Starting Material ◽  
Deep Mantle

Experimental and analytical methods, starting material, and characterization of experimental run products.<br>

scholarly journals Supplemental Material: Water transfer to the deep mantle through hydrous, Al-rich silicates in subduction zones

2021 ◽  
Author(s):  
Joerg Hermann ◽  
Shayne Lakey
Keyword(s):  
Analytical Methods ◽  
Subduction Zones ◽  
Water Transfer ◽  
Starting Material ◽  
Deep Mantle

Experimental and analytical methods, starting material, and characterization of experimental run products.<br>

Shear wave anisotropy in textured phase D and constraints on deep water recycling in subduction zones

2013 ◽  
Vol 377-378 ◽  
pp. 13-22 ◽  
Author(s):  
Angelika D. Rosa ◽  
Carmen Sanchez-Valle ◽  
Carole Nisr ◽  
Shaun R. Evans ◽  
Regis Debord ◽  
...  
Keyword(s):  
Shear Wave ◽  
Deep Water ◽  
Subduction Zones ◽  
Water Recycling

Upper ocean salinity variabilities in the Southern Ocean responding to the recent surface salting in perspective of climate changes

2021 ◽  
Author(s):  
Ling Du ◽  
Xubin Ni
Keyword(s):  
Southern Ocean ◽  
Deep Water ◽  
Water Mass ◽  
Water Cycle ◽  
Upper Ocean ◽  
Tropical Ocean ◽  
Circumpolar Deep Water ◽  
Salinity Changes ◽  
Ocean Salinity ◽  
The Antarctic

&lt;p&gt;Water cycle have prevailed on upper ocean salinity acting as the climate change fingerprint in the numerous observation and simulation works. Water mass in the Southern Ocean accounted for the increasing importance associated with the heat and salt exchanges between Subantarctic basins and tropical oceans. The circumpolar deep water (CDW), the most extensive water mass in the Southern Ocean, plays an indispensable role in the formation of Antarctic Bottom Water. In our study, the observed CTDs and reanalysis datasets are examined to figure out the recent salinity changes in the three basins around the Antarctica. Significant surface salinity anomalies occurred in the South Indian/Pacific sectors south of 60&amp;#186;S since 2008, which are connected with the enhanced CDW incursion onto the Antarctic continental shelf. Saltier shelf water was found to expand northward from the Antarctica coast. Meanwhile, the freshening of Upper Circumpolar Deep Water(UCDW), salting and submergence of Subantarctic Mode Water(SAMW) were also clearly observed. The modified vertical salinity structures contributed to the deepen mixed layer and enhanced intermediate stratification between SAMW and UCDW. Their transport of salinity flux attributed to the upper ocean processes responding to the recent atmospheric circulation anomalies, such as the Antarctic Oscillation and Indian Ocean Dipole. The phenomena of SAMW and UCDW salinity anomalies illustrated the contemporaneous changes of the subtropical and polar oceans, which reflected the meridional circulation fluctuation. Salinity changes in upper southern ocean (&lt; 2000m) revealed the influence of global water cycle changes, from the Antarctic to the tropical ocean, by delivering anomalies from high- and middle-latitudes to low-latitudes oceans.&lt;/p&gt;

Development of the Next Generation Thermoplastic Hose Umbilical

2017 ◽  
Author(s):  
Alan Rutherford ◽  
Alan Dobson
Keyword(s):  
High Temperature ◽  
Deep Water ◽  
Development Program ◽  
Temperature Stability ◽  
Steel Tube ◽  
Polymer Materials ◽  
Asia Pacific ◽  
Next Generation ◽  
The North ◽  
Functional Components

Thermoplastic Control Umbilicals, as shown in Figure 1, have been deployed subsea for decades globally. Typically, these have been installed in harsh dynamic environments such as the North Sea, very cold environments such as the North Atlantic and very warm environments such as the coastal waters of Middle East and Asia Pacific. The inherent fatigue and corrosion resistance of the functional components can offer significant operational advantages while umbilical make-up and manufacturing process can offer significant cost and schedule advantages. As the industry has moved into deeper warmer water regions since the late 1990’s, such as the Gulf of Mexico and West Africa, some of the limitations of conventional thermoplastic umbilicals, such as inherent collapse resistance or design working pressures became barriers for the adoption of the technology. In recent years there have been many new polymer materials developed that provide increased tenacity and temperature stability which subsequently have enabled an evolution in thermoplastic hose technology. This has facilitated the development of the next generation of high temperature, high pressure, collapse resistant hoses that can be deployed in deep water. This paper defines the testing carried out on the constituent parts of the composite hose primarily focusing on the liner and details typical modes of degradation associated with high temperature, pressure or tension. The new material technologies will be benchmarked against conventional materials traditionally used in less aggressive environments. This paper will detail the results of the development program aimed at optimising the hose design process and implementing the cutting edge materials in order to qualify a robust series of hose designs qualified to the stringent requirements of ISO 13628-5 [1]. The paper will also detail the development of the new termination coupling which has been developed in parallel with the next generation hose and which provides a reliable and robust method of coupling the hose to the subsea control system or joining two lengths of hose together. The paper will conclude with a case study comparing a typical deep water installation of a steel tube umbilical with an equivalent thermoplastic umbilical, highlighting the benefits of the new thermoplastic umbilical designs.

Sign in / Sign up

Export Citation Format

Share Document