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| Scientific Investigations Report 2006-5004 |
ONLINE ONLY
Along the course of the Red River, between the town of Red River, New Mexico, and the U.S. Geological Survey streamflow-gaging station near Questa, New Mexico, there are several catchments that contain hydrothermally altered bedrock. Some of these alteration zones have been mined and others have not, presenting an opportunity to evaluate differences that may exist in the mass loading of metals from mined and unmined sections. Such differences may help to define pre-mining conditions. Spatially detailed chemical sampling at stream and inflow sites occurred during low-flow conditions in 2001 and 2002, and during the synoptic sampling, stream discharge was calculated by tracer dilution. Discharge from most catchments, particularly those with alteration scars, occurred as ground water in large debris fans, which generally traveled downstream in an alluvial aquifer until geomorphic constraints caused it to discharge at several locations along the study reach. Locations of discharge zones were indicated by the occurrence of numerous inflows as seeps and springs. Inflows were classified into four groups, based on differences in chemical character, which ranged from near-neutral water showing no influence of mining or alteration weathering to acidic water with high concentrations of metals and sulfate. Acidic, metal-rich inflows occurred from mined and unmined areas, but the most-acidic inflow water that had the highest concentrations of metals and sulfate only occurred downstream from the mine. Locations of ground-water inflow also corresponded to substantial changes in stream chemistry and mass loading of metals and sulfate. The greatest loading occurred in the Cabin Springs, Thunder Bridge, and Capulin Canyon sections, which all occur downstream from the mine. A distinct chemical character and substantially greater loading in water downstream from the mine suggest that there could be impacts from mining that can be distinguished from the water draining from unmined areas.
This report is contained in the following file:
Abstract
Introduction
Physical Setting, General Geology and Hydrology, and Mining History
Geographic and Physiographic Features
Climate and Vegetation
General Geology
Mining History
General Hydrology
Surface Water
Ground Water and Aqueous Geochemistry
Methods for Mass-Loading Analysis
Tracer Injections and Stream Discharge
Synoptic Sampling and Analytical Methods
Constituent Loads
Alluvial Aquifer Geomorphology
Cluster Analysis for Sample Classification
Field-Scale Experiments
Discharge
Chemical Variation of Synoptic Samples
Inflows
Stream
Load Profiles
Load in 2001 versus 2002
Principal Locations of Mass Loading
Sulfate
Alkalinity
Fluoride
Aluminum
Manganese
Zinc
Implications for Mined versus Unmined Sections
Summary and Conclusions
References Cited
Appendix
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