Assignment: Find and read a structure/tectonics paper that uses paleomagnetism to measure local rotations, distributed deformation, or apparent polar wander paths. Prepare a 10 minute (+/-) presentation of this paper to share in class next Wednesday (2/23). Your presentation outline: authors, problem addressed, methods, results, your thoughts. You can find papers which reference others (e.g. Doughty & Sheriff, Jolly & Sheriff, Sheriff, Gunderson & Sheriff) by using cited reference search in the Mansfield Library’s Web of Knowledge/Web of Science multidisciplinary index. I'll listen for your understanding of paleomagnetism.

2/16: Buried dipole applet & NW Montana, magnetic anomalies vs latitude (1, 2, 3, 4). Magnetic prospecting; Montana aeromagnetics (with geology, data, grid) HRAM example Grauch & Hudson, 2007 (field, faults). Total field (scalar) anomalies, fluxgate, proton precession (2) and cesium vapor magnetometers - details from GEM Systems.

2/21: Presidents go skiing...

2/23: Your presentations and problems for next week (the spreadsheet, Solver demo, xls) and a quick look at vector end point diagrams (vector mixing, components).

2/28: Poisson's relation, then 2D, 2.5D, and 3D modeling: Talwani algorithm,

3/2: Discuss the homework, a new problem set, then: Software: pblock, pdike, (Cooper's Software, mine). And maybe Fourier series and filters in the frequency domain - high pass, low pass, bandpass, notch, and threshold. (better images: Fourier_demo(.ppt).

3/7: Return problems; Euler Pole prob-xls; Fourier examples: my.ppt, Fourier series applet, Fourier transform applet, 2D power/amplitude spectra. Good definitions & explanations: Fourier series and transforms.

3/9: 2D power/amplitude spectra (the filters). Magnetics of a randomly magnetized layer (filters: depth,{you could compare pblock}), radial averages, upward continuation (ppt, pdf) & separation filtering (data). Frequency filtering of potential fields.

3/14: Separation of regional/residual and qualitative depth to source; magnetics of a random layer with slope~depth; radial averages.

3/16: Instrument precision & stacking (.xlsx, signal/noise); separation of regional/residual; statistical methods (Spector & Grant Figure (1, 2)). Applications: Acquisition, gridding & contouring (figure: 4 methods) with Surfer (data); the USGS extensions to Oasis Montaj: decorrugation (PowerLine), upward continuation (Yellowstone Lake#5), RTP, radial power spectra (MYAP data, grid);

3/21: Reduction to pole (RTP with latitude, Blakely excerpt), pseudogravity (Blakely excerpt; Chicxulub 2010 (ref)), and matched filtering (step-by-step, MYAP example.ppt, filter choices).

3/23:Public data (Geonet; MT_Geol.kmz; NW_Montana (dat, grd, kmz); Beaverhead (mag, grav)).
In the Lab CHCB11; data, Oasis Montaj, and the USGS extensions. Assignment:

• Make a new folder on the desktop, using your name or something distinct. Do all your downloads and calculations in this folder; it will end up with lots of files!
• Choose one of the Montana data sets (NW_MT, NC_MT, SW_MT) and use Surfer to experiment, grid, and visualize the data appropriately. Alternatively, choose an area in the US or Canada in which you are more interested in which case you'll need to change longitude, latitude pairs to UTM coordinate pairs; I use Corpscon.
• Experiment with RTP (reduction to pole) and upward continuation using the USGS/Oasis Montaj package; learn to separate deeper sources from more shallow sources using equivalent layers and subtracting upward continuations. Put together a good, explanatory graphic presentation and show it to me.
• For matched filtering the computers in CHCB11 have to be booted in Window's SAFE MODE (rattle F8 while rebooting!!)
• For these data from Yellowstone (acquired at 5Hz with a one meter line spacing), use matched filtering to separate equivalent layers and remove the near surface noise - show me
• Use upward continuation of these data acquired over a visible stone ring to determine how deep you could bury them and still see the magnetic anomaly.
• Think about all this as you do it and make sure you understand what you are doing.

3/28: MIDTERM - in class

3/30: Questions and some more lab stuff:

• For these magnetic data from the MacKenzie dike swarm, extract (from .dat) a 20 km x 20 km section that has dikes and other sources, and see how well you can separate the signals from dikes versus that from deeper sources.
• For these archaeological scale data, grid, clean, separate and present the results as best you can. That is, separate regional and noise components to best isolate anomalies at the meter scale.

4/11: Edge detection: First vertical and second vertical derivatives, HGM, analytic signal (low latitudes), local wavenumber, tilt derivative.

4/13: More edge detection, fabric analysis: compare 2VD, HGM, AS, TiltD; and disk w/ Montaj.

Lab assignment (your turn) - edge detection on single and mixed anomalies:

• Use horizontal gradient, analytic signal, local wavenumber, and tilt derivative analysis on the TMI from a set of simulated kimberlite pipes. You might first have to reduce the noise a bit. Email me a 1-3 page analysis (not counting color figures) of the methods with respect to these data. Include a figure comparing (overlay) the maxima of the horizontal gradient and analytic signal on the zero contour of the tilt derivative.
  
  
• Use horizontal gradient, analytic signal, local wavenumber, and tilt derivative analysis on the Mackenzie Dike data. Email me a 1-3 page analysis (not counting color figures) of the methods with respect to these data. Include a figure (overlay) plotting the maxima of the local wavenumber.

• Read this for self assessment: Phillips, 1998 - it should be making sense.

4/20: Edges and enhancement - good Grauch .ppt. Depth estimates: slope half-slope (example). Euler deconvolution (figures: 1, 2, low latitude); least squares/simultaneous equations explained. Example - calculate for Stevensville grid and compare the inverse result.

4:/25: More Euler deconvolution - finish our solution on clipped grid then into Voxler; example figures:(sphere, combined solutions, low latitude); informational papers: 1, 2.

4/27: Euler results from an operational computer: Euler.dat, Stevi.wmv. Werner deconvolution (Stevi example). MAGCAD in DOSBOX (mount c c:\) - forward models! Models from Surfer.

5/2: Depth estimates from the analytic signal and horizontal gradient. Curvature/special function depth analysis; from Phillips et al., 2007 on curvature. Assignment: read for self assessment and discussion: Li et al., 2005.

5/4: Gridding-MacKenzie Dikes @ 100m_kmz; the grids (100m, 1000m), sampling/gridding.ppt, Stevi-Werner example. Magnetic modeling using models from Surfer and PFmag3D (program) from R. Blakely in the USGS DOS  software collection; Faulted Dome (function, model, TMI). Using Phillip's Special Function Depth Analysis in Oasis.

5/10: Final Exam: 3:20 - 5:20, Tuesday 5/10 - we'll meet for discussion but the TAKEHOME EXAM is due Thursday at 6:00 PM by email (to allow color figures; you can print it if you'd rather). Recreational inverse solutions from UBC-GIF: Philipsburg Batholith (Pburg.ppt,.wmv, .wmv2, Darby.wmv) and then invert the faulted dome model (zipped).

The Spring 2010 course

The Spring 2009 course

The Spring 2008 course.