USGS Home
Contact USGS
Search USGS

About USGS /  Science Topics /  Maps, Products & Publications /  Education / Publication: FAQ

LASL: San Juan Mountains Study Area
Geochemical samples were collected during May-July 1976 as part of the Los Alamos Scientific Laboratory (LASL) San Juan Mountains NURE Hydrogeochemical and Stream Sediment Reconnaissance (HSSR) study. This rectangular study area encompassed parts of the Cortez, Durango, Moab, and Montrose quadrangles. A total of 1,982 sediment and 1,706 water samples were collected from 1,995 sites and analyzed for uranium. These data were published in the San Juan Mountains NURE HSSR study GJBX-22(77) report. The Montrose quadrangle part of the San Juan Mountains study was the area between 38°N and 38.5°N latitude and 107°W to 108°W longitude and contained 505 sediment and 436 water samples from 505 locations.

LASL: Montrose Quadrangle
The remainder of the Montrose quadrangle was sampled during July-October 1977. These additional 1,370 sediment and 947 water samples (from 1,410 locations) were analyzed for uranium and up to 43 additional elements. These sample data plus those from the Montrose quadrangle part of the San Juan Mountains study were released as the Montrose Quadrangle NURE HSSR study GJBX-125(79) report. In this quadrangle report the original San Juan Mountains study samples were given new ID numbers and in some records, errors were apparently corrected.

LASL: Sawatch Range (Eastern Montrose Quadrangle) Detailed Study
A follow-up, intermediate-density geochemical survey collected an additional 2,087 sediment and 1,034 water samples from 2,088 locations in the Sawatch Range Detailed Study area of the Montrose quadrangle during September-October 1979. The objective of this study was to follow-up on uranium anomalies found in the region of the Sawatch Range of Colorado during the Montrose Quadrangle NURE HSSR study. The samples were analyzed for uranium and up to 45 additional elements. These data were released as the Eastern Montrose Quadrangle Detailed Study GJBX-105(81) report.

Summary Tables
The following is a list of NURE sample types collected for all studies within the Montrose quadrangle.

The Montrose quadrangle samples were analyzed by one or more of the following methods:

Sediment Samples

• LA1: Los Alamos Delayed-Neutron Counting Analysis of sediments for U.
• LA2: Los Alamos Energy Dispersive X-Ray Fluorescence Analysis of sediments for Ag, Bi, Cd, Cu, Nb, Ni, Pb, Sn, and W. (Quadrangle Study samples only.)
• LA3: Los Alamos Energy Dispersive X-Ray Fluorescence Analysis of sediments for Ag, As, Bi, Cd, Cu, Nb, Ni, Pb, Se, Sn, W, and Zr. (Detailed Study samples only.)
• LA4: Los Alamos Arc-Source Emission Spectrography Analysis of sediments for Be and Li.
• LA5: Los Alamos Neutron Activation Analysis of sediments for Al, Au, Ba, Ca, Ce, Cl, Co, Cr, Cs, Dy, Eu, Fe, Hf, K, La, Lu, Mg, Mn, Na, Rb, Sb, Sc, Sm, Sr, Ta, Tb, Th, Ti, V, Yb, and Zn.

Water Samples

• LA6-DN: Los Alamos Delayed-Neutron Counting Analysis of waters for U.
• LA6-FL: Los Alamos Fluorometry Analysis of waters for U.
• LA7: Los Alamos Plasma-Source Emission Spectrography Analysis of waters for Ca, Co, Cr, Cu, Fe, Mg, Mn, Mo, Ni, Pb, Ti, and Zn. (Quadrangle Study samples only.)

Discussion of the Reformatting Process for Montrose Quadrangle

The Montrose quadrangle sediment and water data consist of reformatted records from the Montrose Quadrangle NURE HSSR study GJBX-125(79) report combined with records from the Montrose portion of the San Juan Mountains NURE HSSR study GJBX-22(77) report plus reformatted records from the Eastern Montrose Quadrangle Detailed Study GJBX-105(81) report. The following problems were found and addressed during the comparison and reformatting stages for the Montrose quadrangle data:

1. During the NURE sample collection phase, LASL sites and samples were initially assigned a 6-digit integer Identification Number (LASLID) starting with 000001. After 1977, most LASL sites were reassigned a new 1-letter+5-digit Identification Number starting with A00001. All LASL samples and the early LASL reports use the 6-digit integer LASLID. Most of the later reports only use the 1-letter+5-digit LASLID. Although both sets of numbers were usually assigned sequentially, they do not correspond one to one with each other: 100001 does not equal C00001, etc. Whenever possible, the 1-letter+5-digit LASL Identification Number was saved in the LASLID field. When the corresponding 6-digit site number could be determined from sample number translation key lists or other sources, this Identification Number was saved in the SITE field.
2. The correlation of the two LASL Identification Numbers for samples in the Montrose quadrangle was first solved by comparing records from the San Juan Mountains NURE HSSR study GJBX-22(77) report with those from the Montrose Quadrangle NURE HSSR study GJBX-125(79) report. Later a LASL Identification Number translation key was found for the Montrose quadrangle sediment samples and the values were confirmed. Additional 1-letter+5-digit LASL Identification Number values were found in the translation key for the 1,370 sediment samples collected in the quadrangle after the San Juan Mountains NURE HSSR study. The 1-letter+5-digit LASL Identification Number was saved in the LASLID field and the corresponding 6-digit site number was manually added to the SITE field. Therefore, the LASLID field contains the Identification Number found in the Montrose Quadrangle NURE HSSR study GJBX-125(79) report. The SITE field contains the corresponding LASL Identification Number used to label the original field maps, field notes, and sample containers and reported in the San Juan Mountains NURE HSSR study GJBX-22(77) report.
3. No LASL Identification Number translation key was found for the Eastern Montrose Quadrangle Detailed Study sediment samples. The 6-digit LASL Identification Number found in LASLID was also added to the SITE field. Therefore, the value found in the LASLID and SITE fields is same LASL Identification Number used to label the original field maps, field notes, and sample containers as well as the value published in Eastern Montrose Quadrangle Detailed Study GJBX-105(81) report.
4. Corresponding records for 486 sediment samples were found in both the San Juan Mountains NURE HSSR study GJBX-22(77) and Montrose Quadrangle NURE HSSR study GJBX-125(79) reports. Each set of corresponding records were compared and combined into a single composite record.
5. When combining corresponding sediment records from the San Juan Mountains NURE HSSR study GJBX-22(77) and Montrose Quadrangle NURE HSSR study GJBX-125(79) reports, some differences between corresponding records were found in the scintillometer reading(SCIN) or sample type(SAMPTYP) fields. These differences appear to be due to corrections added to the later Montrose Quadrangle NURE HSSR study GJBX-125(79) report. Therefore when differences were found, the value from the Montrose Quadrangle NURE HSSR study GJBX-125(79) report was retained in the field and the differing value from the San Juan Mountains NURE HSSR study GJBX-22(77) report was added as a comment to the REFORMAT field. However, when values for these fields were missing in records from the Montrose Quadrangle study but present in records from the San Juan Mountains study, the San Juan Mountains study values were added to the combined record. These changes were also noted in the REFORMAT comment fields.
6. When combining corresponding sediment records from the San Juan Mountains NURE HSSR study GJBX-22(77) and Montrose Quadrangle NURE HSSR study GJBX-125(79) reports, differences in latitude(LAT) and longitude(LONG) coordinates were found for 332 sediment samples. These differences appear to be due to corrections added to the later Montrose Quadrangle NURE HSSR study GJBX-125(79) report. Therefore when differences were found, the value from the Montrose Quadrangle NURE HSSR study GJBX-125(79) report was retained in the field and the differing value from the San Juan Mountains NURE HSSR study GJBX-22(77) report was added as a comment to the COORDPRB field.
7. One sample record contained an invalid value for the scintillometer reading(SCIN) of -655. Although the most likely source of this error is an unwanted negative sign, this could not be confirmed in published sources. This value was removed from the SCIN field and added as a comment to the REFORMAT field.
8. Two sediment sample records contained values for the well pump type(WELLPUMP). This parameter was not normally recorded for sediment sample records. The values were removed from each record and added as a comment to the corresponding REFORMAT field.
9. Unlikely sample collection dates were found for twenty-five samples. These dates were removed from the SAMPDAT field. For each record, the original SAMPDAT value and the most likely correct value was added as a comment to the REFORMAT field.
10. Ten sediment samples in this quadrangle share the same latitude-longitude coordinates with one other sample (5 distinct coordinate sites). These appear to be sites collected during Montrose quadrangle study that were resampled during the Eastern Montrose Quadrangle detailed study. A comment in the COORDPRB field identifies each of these pairs.

1. The correlation of the two LASL Identification Numbers for samples in the Montrose quadrangle was first solved by comparing records from the San Juan Mountains NURE HSSR study GJBX-22(77) report with those from the Montrose Quadrangle NURE HSSR study GJBX-125(79) report. Later a LASL Identification Number translation key was found for the Montrose quadrangle water samples and the values were confirmed. Additional 1-letter+5-digit LASL Identification Number values were found in the translation key for the 947 water samples collected in the quadrangle after the San Juan Mountains NURE HSSR study. The 1-letter+5-digit LASL Identification Number was saved in the LASLID field and the corresponding 6-digit site number was manually added to the SITE field. Therefore, the LASLID field contains the Identification Number found in the Montrose Quadrangle NURE HSSR study GJBX-125(79) report. The SITE field contains the corresponding LASL Identification Number used to label the original field maps, field notes, and sample containers and reported in the San Juan Mountains NURE HSSR study GJBX-22(77) report.
2. Corresponding records for 428 water samples were found in both the San Juan Mountains NURE HSSR study GJBX-22(77) and Montrose Quadrangle NURE HSSR study GJBX-125(79) reports. Each set of corresponding records were compared and combined into a single composite record.
3. When combining corresponding water records from the San Juan Mountains NURE HSSR study GJBX-22(77) and Montrose Quadrangle NURE HSSR study GJBX-125(79) reports, differences in latitude(LAT) and longitude(LONG) coordinates were found for 284 water samples. These differences appear to be due to corrections added to the later Montrose Quadrangle NURE HSSR study GJBX-125(79) report. Therefore when differences were found, the value from the Montrose Quadrangle NURE HSSR study GJBX-125(79) report was retained in the field and the differing value from the San Juan Mountains NURE HSSR study GJBX-22(77) report was added as a comment to the COORDPRB field.
4. Unlikely sample collection dates were found for twenty-one samples. These dates were removed from the SAMPDAT field. For each record, the original SAMPDAT value and the most likely correct value was added as a comment to the REFORMAT field.
5. Two water samples in this quadrangle share the same latitude-longitude coordinates with one other sample (1 distinct coordinate site). This appears to be a site collected during Montrose quadrangle study that was resampled during the Eastern Montrose Quadrangle detailed study. A comment in the COORDPRB field identifies each of these records.

Download The Data

The NURE HSSR data are now available online in two databases: The sediment database (also includes data for soils and some rocks) at http://tin.er.usgs.gov/nure/sediment/ and the water database at http://tin.er.usgs.gov/nure/water/. From these two web sites, NURE HSSR data can be selected, examined, summarized, and downloaded by political boundaries (State and County), by quadrangle (1:250,000-scale, 1:100,000-scale, and 1:63,360-scale for Alaska or 1:24,000-scale for the Lower 48 States), and by hydrologic unit (drainage region, subregion, river basin, or sub-basin). Selected data can be downloaded as a dBase file, a shapefile, an HTML table, or ASCII text (tab- or comma-delimited).

Montrose Quadrangle Sediment Data - 3,962 records
Montrose Quadrangle Water Data - 2,417 records

Notes for Data Users

None at this time.

Other NURE Geochemical Data for the Montrose Quadrangle

Montrose Quadrangle NURE Summary
A summary evaluation report was prepared for the Montrose quadrangle by the Bendix Field Engineering Corp. [GJQ-010(81)]. As part of the evaluation, an additional 365 rock, 30 stream sediment, and 55 water (stream, spring, adit, and well) samples were collected from selected areas of the quadrangle. The analytical data for these samples were released only as appendices on microfiche accompanying the summary report.

Uranium Resource Assessment Using Statistical Analysis of Durango, Montrose, Pueblo, and Trinidad Quadrangles Data
The University of Georgia, under subcontract to Bendix Field Engineering Corp., evaluated the Durango, Montrose, Pueblo, and Trinidad quadrangles to "develop a practical system for quantitatively assessing the uranium resources in individual quadrangles based upon the HSSR data and tonnage/grade data for occurrences." No additional geochemical data accompany this statistical analysis GJBX-140(81) report.

Montrose Quadrangle Multivariate Statistical Analyses
The Los Alamos Scientific Laboratory conducted multivariate statistical analyses of the Montrose quadrangle NURE HSSR data to evaluate the potential for strategic and other commercially important mineral resources. The interpretations of these procedures were reported in the GJBX-218(82) report. No additional geochemical data accompany this report.

Montrose Quadrangle Integration Methods Study
The Los Alamos Scientific Laboratory investigated digital and statistical methods for integrating the Montrose quadrangle HSSR geochemical data, the Sawatch Range Detailed Study geochemical data, airborne radiometric and aeromagnetic data, known uranium occurrences, geologic map and LANDSAT imagery. The results of this study were reported in GJBX-148(81) and Bolivar and others (1983). No additional geochemical data accompany these reports.

Waterloo Gulch Study
The Bendix Field Engineering Corporation conducted a detailed follow-up study to evaluate a uranium anomaly in Waterloo Gulch of the Sawatch Range. Three new stream-sediment and seven new rock samples were collected and analyzed for U by fluorometry, and for 35 elements by emission spectroscopy. These data are listed in an appendix to the report [GJBX-1(84)].

Mt. Harvard 15' Quadrangle Study
Bendix Field Engineering Corporation also conducted a study to "demonstrate the applicability of National Uranium Resource Evaluation (NURE) geochemical and geophysical data acquired during detailed and reconnaissance-scale surveys to the identification of anomalous geochemical characteristics in a detailed (...) study area." The Mt. Harvard 15-minute quadrangle in the Sawatch Range of Colorado was selected for this study [GJBX-6(84)]. The study was based on existing NURE HSSR and detailed geochemical data and aerial radiometric and magnetic geophysical data. No additional geochemical data accompany this report.

Montrose Quadrangle NURE Bibliography

• Bolivar, S.L., Balog, S.H., Campbell, K., Fugelso, L.E., Weaver, T.A., and Wecksung, G.W., 1981, Multisource data set integration and characterization of uranium mineralization for the Montrose quadrangle, Colorado: Los Alamos Scientific Laboratory informal report LA-8807-MS, Los Alamos, N.M., U.S. Department of Energy, Grand Junction, Colo., GJBX-148(81), 172 p.
• Bolivar, S.L., Campbell, K., and Wecksung, G.W., 1983, R-mode factor analysis applied to uranium exploration in the Montrose quadrangle, Colorado, in Parslow, G.R., ed., Geochemical Exploration 1982: Journal of Geochemical Exploration, v. 19, no. 1/3, p. 723-743.
• Broxton, D.E., Morris, W.A., and Bolivar, S.L., 1979, Uranium hydrogeochemical and stream sediment reconnaissance of the Montrose NTMS quadrangle, Colorado, including concentrations of forty-three additional elements: Los Alamos Scientific Laboratory informal report LA-7507-MS, Los Alamos, N.M., U.S. Department of Energy, Grand Junction, Colo., GJBX-125(79), 255 p.
• Byeth, M., Broxton, D., McInteer, C., Averett, W.R.,, and Stablein, N.K., 1982, Analysis of stream sediments reconnaissance data for mineral resources from the Montrose NTMS quadrangle, Colorado: Los Alamos Scientific Laboratory informal report LA-8329-MS, Los Alamos, N.M., U.S. Department of Energy, Grand Junction, Colo., GJBX-218(82), 95 p.
• Goodnight, C.S., and Ludlam, J.R., 1981, National Uranium Resource Evaluation, Montrose quadrangle, Colorado: Bendix Field Engineering Corporation, U.S. Department of Energy, Grand Junction, Colo., GJQ-010(81), 91 p.
• Koch, G.S., Jr., Howarth, R.J., and Schuenemeyer, J.H., 1981, Uranium resource assessment through statistical analysis of exploration, geochemical, and other data; final report: U.S. Department of Energy, Grand Junction, Colo., GJBX-140(81), 145 p.
• Ludlam, J.R., 1984, Geochemical characterization of the Mt. Harvard 15-minute quadrangle, Colorado, using NURE data: U.S. Department of Energy, Grand Junction, Colo., GJBX-6(84), 26 p.
• Ludlam, J.R., Goodknight, C.S., Dexter, J.J., and Rush, S.M., 1984, Evaluation of uranium anomalies in the Waterloo Gulch Area, northeastern Gunnison County, Colorado, in Goodknight, C.S., compiler, Reports on field investigations of uranium anomalies: U.S. Department of Energy, Bendix Field Engineering Corporation, Grand Junction, Colo., GJBX-1(84), p. I1-I30.
• Maassen, L.W., Sandoval, W.F., Muller, M., Gallimore, D.L., Martell, C.J., Hensley, W.K., and Thomas, G.J., 1981, Detailed uranium hydrogeochemical and stream sediment reconnaissance data release for the eastern portion of the Montrose NTMS quadrangle, Colorado, including concentrations of forty-five additional elements: Los Alamos Scientific Laboratory informal report LA-8482-MS, Los Alamos, N.M., U.S. Department of Energy, Grand Junction, Colo., GJBX-105(81), 208 p.
• Maxwell, J.C., 1977, Uranium hydrogeochemical and stream sediment reconnaissance in the San Juan Mountains, southwestern Colorado: Los Alamos Scientific Laboratory informal report LA-6651-MS, Los Alamos, N.M., U.S. Department of Energy, Grand Junction, Colo., GJBX-22(77), 104 p.

Links Within Open-File Report 97-492

Back to Colorado NURE data
Frequently Asked Questions Concerning NURE HSSR Data
Home Page: USGS National Geochemical Database - NURE HSSR data

Page written by Steven M. Smith (smsmith@usgs.gov)
Version 1.10: July 29, 1999
Version 1.20: August 07, 2000
Version 1.30: September 11, 2001
Version 1.41: February 23, 2006

AccessibilityFOIAPrivacyPolicies and Notices
U.S. Department of the Interior | U.S. Geological Survey URL: https://pubsdata.usgs.gov/pubs/of/1997/ofr-97-0492/quad/q_montrs.htm Questions or Assistance: USGS Web Contact Page Last Modified: Wed Dec 7 16:14 EST 2016