Geochemical and biogeochemical studies in the Hansonburg Mining District, New Mexico

The Hansonburg mining district is in Socorro county in south central New Mexico. A Paleozoic section of thick Pennsylvanian limestone units, thin shale and arkose layers and thick Permian units of sandstone, siltstone and gypsiferous beds interlayered with thin limestone units unconformably overlie a Precambrian basement of granite. The sedimentary rocks are folded with north trends and plunges. Northerly, some easterly and northwesterly trending faults cut the folds. Galena, fluorite, and barite mineralization occurs along some of the northerly faults and as bedded replacements and fissure fillings in the Pennsylvanian Council Spring limestone. Geological mapping and geochemical soil surveys of the northwestern part of the mining district indicate four major heavy metal anomalous areas and possible regional zoning of the metals. Copper values range from a low of 2.8 ppm to a high of 67.0 ppm. Lead values ranged from 5.3 ppm to 56 ppm, and zinc from below detection limit to 38.0 ppm. Heavy metal determinations were made of soil and Creosote bush samples that were collected across a mineralized fault breccia zone of the Oscura fault. Results show that the lead values in soils in test profiles have distinct anomalous areas which range from 11.5 to 98.0 ppm. Copper and zinc anomalies are also distinct, but, with smaller ranges of 3.5 to 16.0 ppm and 3.0 to 21.5 ppm, respectively. Heavy metals in Creosote bush samples show similar anomalous zones, but copper has the greatest range (12.0 to 65.0 ppm). The range of lead is 5.0 to 28.0 ppm and for zinc, 10.5 to 21.5 ppm. A rising trend of copper and zinc and constant lead content in sediments upstream along the Julian Arroyo suggests possible mineralization within the Alamogordo Bombing Range --Abstract, pages ii-iii