USGS Open-File Report 2010-1095

A Review of Aeromagnetic Anomalies in the Sawatch Range, 
Central Colorado 

The 6 files in this directory with names beginning with 
'mag_polygons_attrib' comprise an Arc-formatted shapefile
layer of 117 polygons and associated attributes.

The polygons were digitized around prominent aeromagnetic
anomalies from the gridded data set 'cc_mag_med.grd', which is a 
bandpass-filtered RTP magnetic grid.  This filter was designed 
using matched filtering (Phillips, 2001), which resulted in 
cutoff values of 0.44 km for the high-pass wavelengths, 1.47 km 
for the "medium" wavelengths, and 11.3 km for the low-pass 
wavelengths.

The attributes are:

polygon_no - polygon number, automatically generated.

hi_or_lo - 'h' or 'l' identifies a relatively high or low 
    aeromagnetic anomaly.

topo_rel - 'yes', 'no', or 'partly' indicates whether or not
    the anomaly is spatially correlated with a topographic
    high or low.

topo_notes - describes any pertinent information about the 
    local topography.

rock_rel - 'yes', 'no', or 'partly' indicates whether or not
    the anomaly is spatially correlated with mapped rocks.

rock_type - describes any pertinent information about the 
    local geology.

refs - lists any previous reports that discuss this anomaly,
    and the anomaly identification, if any.  Complete 
    references are listed in the main report.
      PP726-C - Tweto and Case, 1972 (Leadville)
      MF1236-C - Campbell, 1981 (Hunter-Fryingpan)
      MF1647-B - Campbell, 1985 (Maroon Bells-Snowmass)
      MF1841-B - Campbell and Wallace, 1986 (Holy Cross)
      Bull 1636 - Van Loenen and others, 1989 (Mt. Massive)
      I-1419-C - Boler and Klein, 1990 (Pueblo)

description - describes any pertinent information about the 
    local geology described in these reports.


Projection:  UTM Zone 13N
Datum: NAD-27-USA
Base Latitude: 0.00 degrees
Central Meridian: -105.00 degrees
False Easting:  500,000 meters
False Northing: 0 meters