Description and chemical composition of the fossil manganese nodules of the Cambrian manganese deposits of Conception and Trinity bays, Newfoundland

This paper is based upon data collected during the summers of 1912 and 1913. Mr. A. O. Hayes and Prof. van Ingen of Princeton University, while making a study of the general geology, stratigraphy, and palaeontology of the shores of Conception Bay, Newfoundland, came upon the manganiferous rocks of the Lower Cambrian exposed at Manuels, Topsail, Brigus, and other places. The following summer, of 1913, the writer as a member of the Princeton Newfoundland Expedition undertook a more detailed study of these deposits. In this paper therefore there has been an attempt to present as comprehensive a study of the manganese of southeastern Newfoundland. It is primarily chemical in its nature and the analyses herewith presented are from samples taken from the principal manganese-bearing beds.

Description and chemical composition of ferromanganese deposits from Trout Lake, northern Wisconsin

Sediments were collected with Eckman and Petersen dredges from the bottom of Trout Lake, northern Wisconsin, at 221 stations. Sampling was done with a spud sampler at 32 stations, and core samples were obtained with a Jenkins and Mortimer and a Twenhofel sampler at 17 stations. The shore and offshore deposits of the shores of Trout Lake and the shores of the islands are described. Megascopic descriptions are given of the samples collected with the Eckman and Petersen dredges. Sediments on bottoms of about 10 meters or deeper are mainly gyttja, or crusts composed of mixtures of organic matter, ferric hydroxide, and some form of manganese oxide. The latter deposits are extensive. Detailed descriptions of some of the samples of sands are given, and generalizations respecting size and distribution are made. Tables showing quartiles, medians, and coefficients of sorting and skewness of the coarse sediments collected from the bottom are given in tables. Mechanical analyses of all fine sediments, mainly gyttja, were not made, as previous experience seems to have demonstrated that results have no sedimentational value. Organic matter of the gyttja was determined and also the percentages of lignin in the organic matter. Core samples are composed almost entirely of fine materials, mainly gyttja, and determinations were made on these samples in the same way as on the samples obtained with the Eckman and Petersen dredges. Studies of the core samples show that the fine sediments usually contain in excess of 90 per cent moisture and there is very little change in the moisture content from top to bottom of cores. A map shows the distribution of the iron and manganese deposits. These deposits were found to contain 10 to 20 per cent of organic matter, 11 to 16 per cent of metallic iron, and 12 to 30 per cent of metallic manganese. No stratification of any kind was found in any of the deep-water sediments of Trout Lake except in the iron and manganese crusts. Absence of stratification is considered to be due to the slow rate of deposition and the mixing of sediments by organisms which dwell in them. The data indicate that the rate of deposition in the deep waters of Trout Lake is of the order of 1 foot in 15,000 years.

Description and chemical composition of manganese nodules collected in the Pacific Ocean

Chemical and X-ray analyses were performed on the fifteen manganese nodules collected from the Pacific Ocean floor. The results were discussed compared with the previous data on the manganese nodules. Minerals were found to be todorokite, delta-MnO2 and other silicates, montmorillonite, illite, phillipsite and alpha-Si02. Average composition shows that copper is concentrated on the deep sea nodules more than the shallow ones, and that the todorokite rich nodules contain more copper and nickel than the delta-MnO2 rich ones. The analyses of fresh water iron-manganese precipitates by bacterial activity suggest that biological process is one of the important factors on the genesis of the sedimentary iron-manganese deposits, in¬cluding the manganese nodule.

La lucha contra la selva. Percepciones y usos de la naturaleza entre los colonos misioneros. En: Avá, nº 15

En este artículo se presentan los esquemas generales en base a los que, los pequeños y medianos productores rurales de la provincia de Misiones, se relacionan con aquel ámbito que reconocen como “naturaleza”. El análisis de la lógica de la naturaleza se realiza distinguiendo espacios en que los productores se mueven en su vida cotidiana, y las distinciones de uso entre géneros. La lógica local de la naturaleza está directamente ligada al modelo de producción rural que predominó en la región durante todo el siglo XX, y comienza a tener transformaciones a partir de presencia local de discursos y propuestas ambientalistas.

Víctor Raúl Haya de la Torre, el APRA y el Indoamericanismo : Victor Raúl Haya de la Torre, the «Apra» and Indo–Americanism

El propósito de este trabajo es reflexionar sobre la importancia histórica, vigencia y protagonismo de personalidades como la de Víctor Raúl Haya de la Torre, abarcando las ideologías que pretendieron imponer sus proyectos y discursos políticos occidentales en la región. Para referirse al aprismo y al indoamericanismo, es menester preguntarse sobre la densidad romántica de las motivaciones que tuvieron los revolucionarios del siglo XIX y de los de la década del 30 para ejercer sus derechos ciudadanos en tiempos de colonización, dependencia y emancipación en medio de los rudimentarios influjos de la modernización. Preguntarse por qué en aquellos tiempos la Patria era Vida y Muerte, fuente de identidad primordial; qué estaban pensando los ideólogos norteamericanos en las últimas décadas del siglo XIX acerca de América Latina y luego dirigir nuestra mirada a Perú, su círculo serrano y costeño como espacio de contradicción migratoria e intercultural.