experimental rock deformation
It is our great pleasure to welcome Cassandra Seltzer to the research group. Cassandra did her undergraduate studies at the University of Michigan in Ann Arbor and will work on the influence of stress on melt network geometry in partially molten mantle rocks!
Cailey Condid started her NSF post-doc in the lab today – Cailey will deform amphibolites to determine their rheological properties at lower crustal pressures and temperatures. Welcome to the lab!
Yesterday was a very long but extremely exciting time in the lab. Hamed has spend the past few days chasing electrical noise and bringing down the background of our piezoelectric sensor. Eventually, Hamed managed to bring the background noise level to about 0.2 V at a 60 dB amplification with a +/- 4V full scale – an excellent value giving us hope to record very small events occurring in our sample. Of course more problems came when we started pressurizing and heating the sample due to A/C and higher frequency noises introduced by the silicon controlled rectifier which is at the core of our heating system. However, both of these noises are at low frequencies and extremely reproducible and therefore were filtered out with a high-pass filter somewhat compromising our detection capabilities. At last, nothing stood in the way of recording about 65 beautiful acoustic emissions during axial compression of Black Hills Quartzite deformed at 1GPa confining pressure and 100˚C. Now the next steps will be further lowering the electrical noise in our system to detect more events, introducing more sensors into the loading column and slowly ramping up the temperature of our experiments – many more exciting nights ahead!
A new paper by Jacqueline Reber and Matej Pec on semi-brittle flow of quartzites is published in Journal of Structural Geology – check it out
Check out our BETA version of newRig program for synchronizing, merging and evaluating data from Sanchez deformation apparatuses. Follow the link to download here
What could the zone in the center of the image be…? Post your best guess in the comments!
Matěj gave a talk at the departmental seminar at LDEO of Columbia University in New York. It was great to talk to all the researchers there and see the ice friction lab.
We ave investigated first Saleh’s experiments using a Scanning Electron Microscope (SEM). Below you can see an overview of a 70:30 k-feldspar : quartz sample deformed at 800 MPa confining pressure and 750˚C, i.e. P-T conditions corresponding to approximately 25 km depth. K-feldspar is bright while quartz is dark. Top and bottom of the sample are large unloading cracks (black) separating the sample from the alumina forcing blocks (gray).
Terry Tullis has lead the first joint meeting between MIT and Brown University. Terry summarized the state-of-the-art in rate-and-state friction. The meeting was video linked to MIT and other universities and research institutions, more then 20 people participated. The goal of our Colaborative Organization for Rock Deformation (CORD) is to encourage and facilitate participation in experimental rock deformation studies by a broader spectrum of scientists within the Earth science community.