Compres

 
earth's core
Original Drawing Created by Keelin Murphy
Home
Welcome

compreslogotiny.jpg COMPRES, the Consortium for Materials Properties Research in Earth Sciences is a community-based consortium whose goal is to enable Earth Science researchers to conduct the next generation of high-pressure science on world-class equipment and facilities. It facilitates the operation of beam lines, the development of new technologies for high pressure research, and advocates for science and educational programs to the various funding agencies.

High Pressure Science at NSLS-II

NSLS-II announces successful beamline development proposals

3 COMPRES - Affiliated Proposals Awarded Type I Status for Beamline Development:

  • 4-Dimensional Studies in Extreme Environments; Spokesperson: Donald J. Weidner
  • Time-resolved X-ray Diffraction and Spectroscopy Under Extreme Conditions; Spokesperson: Alexander Goncharov
  • Frontier Synchrotron Infrared Spectroscopy Beamline Under Extreme Conditions; Spokesperson: Zhenxian Liu

Additional Information about the NSLS:II project can be found here

COMPTECH

COMPRES Technology Center (COMPTECH ) is COMPRES's presence at the Advanced Photon Source, Argonne National Laboratory. It provides tools, software, development and support for High-pressure research at APS.

comptech.compres.us

 

 

Support

nsf1.jpgNSF supports COMPRES, the Consortium for Materials Properties Research in Earth Sciences under NSF Cooperative Agreement EAR 11-43050.

2014 Annual Meeting

2014 ANNUAL MEETING
June 16-19, 2014
Skamania Lodge, WA 

compressml.jpg


 Compressibility of liquid FeS measured using X-ray radiograph imaging

RESEARCH PERFORMED AT COMPRES-SUPPORTED BEAMLINES X17B2

Jiuhua Chen, Tony Yu, Shu Huang, Jennifer Girard, Xiaoyang Liu
PEPI Volume 228, March 2014, Pages 294–299

chen2014fig1sized.jpg

 

Figure:
2-D brightness fitting of the Al2O3 reference sphere in the radiograph (inset) based on Beer-Lambert law to derive density of liquid FeS sample at high pressures. Blue and red symbols are experimental and calculated data, respectively. 

 

Summary:
Density of liquid FeS was measured at 1650 K and pressures up to 5.6 GPa using the X-ray absorption radiograph system of the COMPRES high pressure facility at the X17B2 beamline, NSLS. The experimental data were fitted to the third-order Birch–Murnaghan equation of state to calculate the isothermal bulk modulus (K0) of the liquid, yielding K0 = 11 ± 3 GPa when the pressure derivative of bulk modulus is fixed at 5. Combining this result with those from previous studies on Fe–S liquid system, we suggest an exponential relation between the liquid Fe–S alloy bulk modulus and its sulfur content. The exponential relation and the linear relation present a 14 GPa difference in K0 (60 GPa from the linear relation and 46 GPa from the exponential relation) at the possible liquid outer core composition, 10 wt.%S (or 16 atm% S). This is significant for the core composition modeling.

posted July 2, 2014

Dehydration melting at the top of the lower mantle

RESEARCH PERFORMED AT COMPRES-SUPPORTED BEAMLINE U2A 

Brandon Schmandt, Steven D. Jacobsen, Thorsten W. Becker, Zhenxian Liu, Kenneth G. Dueker; Science 344, 1265-1268 doi: 10.1126/science.1253358

jacobsen2014figsized.jpg

 

Figure:

(A) Single-crystal of hydrous ringwoodite (blue crystal) containing 1 wt % H2O inside a diamond-anvil cell at 30 GPa. The sample was laser heated to 1600°C in several spots (orange circles) to perform direct transformation to bridgmanite and (Mg,Fe)O. Laser heating was conducted at Sector 13 (GSECARS) of the APS. (B) Synchrotron-FTIR spectra of the recovered sample were collected at beamline U2A of the NSLS. Spectrum 1 is an unheated spot, characteristic of hydrous ringwoodite. Spectra 2 and 3 from within the laser heated spots exhibit modified IR-absorption spectra in the OH region, with a broad and asymmetric band at 3400 cm-1 (characteristic of OH in quenched glass) and a sharp peak (3680 cm-1) associated with brucite. On conversion to bridgmanite plus (Mg,Fe)O, dehydration melting occurred as intergranular melt, viewed by TEM in panel C. In this study, dehydration melting was detected just beneath the mantle transition zone from P-to-S converted phases using seismic data from NSF-Earthscope, US-Array.

 

Summary:

The high water storage capacity of minerals in Earth’s mantle transition zone (410- to 660-kilometer depth) implies the possibility of a deep H2O reservoir, which could cause dehydration melting of vertically flowing mantle. We examined the effects of downwelling from the transition zone into the lower mantle with high-pressure laboratory experiments, numerical modeling, and seismic P-to-S conversions recorded by a dense seismic array in North America. In experiments, the transition of hydrous ringwoodite to perovskite and (Mg,Fe)O produces intergranular melt. Detections of abrupt decreases in seismic velocity where downwelling mantle is inferred are consistent with partial melt below 660 kilometers. These results suggest hydration of a large region of the transition zone and that dehydration melting may act to trap H2O in the transition zone.

Posted July 2, 2014