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Record 1 of 11642
Thermochemistry of dense hydrous magnesium silicates
Author and Affiliation:
Bose, Kunal(Princeton Univ., NJ, United States)
Burnley, Pamela(Colorado Univ., Boulder, CO., United States)
Navrotsky, Alexandra(Princeton Univ., NJ, United States)
Abstract: Recent experimental investigations under mantle conditions have identified a suite of dense hydrous magnesium silicate (DHMS) phases that could be conduits to transport water to at least the 660 km discontinuity via mature, relatively cold, subducting slabs. Water released from successive dehydration of these phases during subduction could be responsible for deep focus earthquakes, mantle metasomatism and a host of other physico-chemical processes central to our understanding of the earth's deep interior. In order to construct a thermodynamic data base that can delineate and predict the stability ranges for DHMS phases, reliable thermochemical and thermophysical data are required. One of the major obstacles in calorimetric studies of phases synthesized under high pressure conditions has been limitation due to the small (less than 5 mg) sample mass. Our refinement of calorimeter techniques now allow precise determination of enthalpies of solution of less than 5 mg samples of hydrous magnesium silicates. For example, high temperature solution calorimetry of natural talc (Mg(0.99) Fe(0.01)Si4O10(OH)2), periclase (MgO) and quartz (SiO2) yield enthalpies of drop solution at 1044 K to be 592.2 (2.2), 52.01 (0.12) and 45.76 (0.4) kJ/mol respectively. The corresponding enthalpy of formation from oxides at 298 K for talc is minus 5908.2 kJ/mol agreeing within 0.1 percent to literature values.
Publication Date: Jan 01, 1994
Document ID:
19950015365
(Acquired Dec 28, 1995)
Accession Number: 95N21782
Subject Category: GEOPHYSICS
Coverage: Abstract Only
Document Type: Conference Paper
Publication Information: Lunar and Planetary Inst., Conference on Deep Earth and Planetary Volatiles; p 5
Publisher Information: United States
Financial Sponsor: NASA; United States
Organization Source: Princeton Univ.; Dept. of Geological and Geophysical Sciences.; NJ, United States
Description: 1p; In English
Distribution Limits: Unclassified; Publicly available; Unlimited
Rights: No Copyright
NASA Terms: DATA BASES; DEHYDRATION; EARTHQUAKES; MAGNESIUM; METAMORPHISM (GEOLOGY); PHYSICAL CHEMISTRY; PIPES (TUBES); SILICATES; SUBDUCTION (GEOLOGY); THERMOCHEMISTRY; THERMODYNAMICS; WATER; CALORIMETERS; ENTHALPY; HEAT MEASUREMENT; HIGH PRESSURE; HIGH TEMPERATURE; MAGNESIUM OXIDES; PERICLASE; SILICON DIOXIDE
Imprint And Other Notes: In Lunar and Planetary Inst., Conference on Deep Earth and Planetary Volatiles p 5 (SEE N95-21777 06-46)
Availability Source: Other Sources
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