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J. W. Powell

Publications and source records attributed to J. W. Powell.

At least 19 recordsLinked to original sources
USGS1997

Evidence for hot Mississippi Valley-type brines in the Reelfoot Rift complex, south-central United States, in Late Pennsylvanian-Early Permian

Petrographic and fluid inclusion studies of sparry dolomite cement from Upper Cambrian to Lower Ordovician rocks and conodont thermal-alteration indices provide evidence that hot mississippi valley-type brines were once present in the Reelfoot Rift complex. The cathodoluminescent microstratigraphy of sparry dolomite cement in the Reelfoot Rift resembles that of sparry dolomite cement associated with widespread mississippi valley-type deposition in the Ozark region. If correlative cathodoluminescent zones in the sparry dolomite from the Ozark and Reelfoot Rift regions indicate broadly contemporaneous dolomite deposition, then the results show that the Ozark MVT-type hydrothermal system extended into the Reelfoot region and onto the western flank of the Nashville Dome. Independent evidence supports migration of MVT-type brines into the Ozark region from the Reelfoot Rift complex in late Paleozoic time.

Professional Paper↗
USGS1996

Paragenetic and minor- and trace-element studies of Mississippi Valley-type ore deposits of the Silesian-Cracow district, Poland

Paragenetic and minor- and trace-element studies were conducted on samples of epigenetic ore and gangue minerals collected from mines and drill core in the Silesian-Cracow (S-C) district of southern Poland. Four discrete mineral suites representing four mineralizing stages can be identified throughout the district. The earliest epigenetic minerals deposited during stage 1 consist of a late dolomite cement together with minor pyrite and marcasite. Stage 2 was the first ore-forming stage and included repetitive deposition of sphalerite and galena in a variety of morphologies. Stage 3 abruptly followed the first ore stage and deposited marcasite and pyrite with variable amounts of late sphalerite and galena. In the samples studied, minerals deposited during stage 3 are predominately marcasite-pyrite with minor sphalerite and galena in the Pomorzany and Olkusz mines, whereas, at the Trzebionka mine, stage 3 mineralization deposited mostly galena and sphalerite with little marcasite or pyrite. Stage 4 minerals include contains barite, followed by calcite, with very minor pyrite and a rare, late granular sphalerite. Compared to other major Mississippi Valley-type (MVT) districts of the world, the Silesian-Cracow district contains sphalerite with the second largest range in Ag concentrations and the largest range in Fe and Cd concentrations of any district. Unlike in other districts, very wide ranges in minor- and trace-element concentrations are also observed in paragenetically equivalent samples collected throughout the district. This wide range indicates that the minor- and trace-element content of the ore-forming environment was highly variable, both spatially and temporally, and suggests that the hydrologic system that the ore fluids traversed from their basinal source was very complex. Throughout the district, a significant increase in Tl, Ge, and As concentrations is accompanied by a lightening of sulfur isotopes between stage 2 and stage 3 minerals. This change appears to record a major district-scale hydrologic event that probably reflects the introduction of fluids with significantly different geochemistry than that of earlier ore-forming fluids.

Prace - Panstwowego Instytutu Geologicznego↗
USGS1891

Eleventh Annual report of the Director of the United States Geological Survey, Part 2- Irrigation: 1889-1890

The work of the United States Irrigation Survey during the second year has been carried oil under the appropriation of $250,000 made March 2, 1889, by the force organized and equipped during the previous year. This is pursuant to the purposes outlined in the first annual report, which explains the origin, purpose, and plan of the Survey, publishes the instructions to the chiefs of the larger divisions, and gives the report of the topographic division to the end of the first fiscal year, and the reports of the hydrographic and engineering divisions during the greater part of the calendar year 1889.

Annual Report↗
USGS1889

Eighth annual report of the United States Geological Survey to the Secretary of the Interior, 1886-1887: Part 1

The Geological Survey was organized, with Mr. Clarence King as Director, in March, 1879. In March, 1881, Mr. King resigned and the present Director was appointed. From its organization to the present time the Survey has steadily grown as Congress has enlarged its functions and increased its appropriations. During this time the scientific organization has gradually developed to the condition set forth in the last annual report. It seems advisable now to describe fully the business organization and methods of the Survey, which has heretofore been done only in part. Under the act of July 7, 1884, a joint commission was created to consider the organization of certain scientific bureaus. In the volume of testimony prepared by that commission the business operations of the Geological Survey were in part set forth; but this partial presentation was unsystematic, the facts recorded being elicited in irregular order by interrogatories arising in the course of a long investigation. It is designed here to make a more thorough exposition oi the subject. The business system of the Geological Survey is subordinate to the scientific organization and its character is dependent thereon. The development of the divisions of the Survey whose function is the transaction of business has therefore followed the development of the purely scientific divisions, and overy modification of plan for the scientific work may carry with it some modification of the business organization.

Annual Report↗