Concentrations and accumulation rates of chemical elements and sediment components in sediments of central equatorial Pacific, DSDP data

Accumulation rates of Mg, Al, Si, Mn, Fe, Ni, Cu, Zn, opal, and calcium carbonate have been calculated from their concentrations in samples from equatorial Deep Sea Drilling Project sites. Maps of element accumulation rates and of Q-mode factors derived from raw data indicate that the flux of trace metals to equatorial Pacific sediments has varied markedly through time and space in response to changes in the relative and absolute influence of several depositional influences: biogenic, detrital, authigenic, and hydrothermal sedimentation. Biologically derived material dominates the sediment of the equatorial Pacific. The distributions of Cu and Zn are most influenced by surface-water biological activity, but Ni, Al, Fe, and Mn are also incorporated into biological material. All of these elements have equatorial accumulation maxima similar to those of opal and calcium carbonate at times during the past 50 m.y. Detritus distributed by trade winds and equatorial surface circulation contributes Al, non-biogenic Si, Fe, and Mg to the region. Detrital sediment is most important in areas with a small supply of biogenic debris and low bulk-accumulation rates. Al accumulation generally increases toward the north and east, indicating its continental source and distribution by the northeast trade winds. Maxima in biological productivity during middle Eocene and latest Miocene to early Pliocene time and concomitant well-developed surface circulation contributed toward temporal maxima in the accumulation rates of Cu, Zn, Ni, and Al in sediments of those ages. Authigenic material is also important only where bulk-sediment accumulation rates are low. Ni, Cu, Zn, and sometimes Mn are associated with this sediment. Fe is almost entirely of hydrothermal origin. Mn is primarily hydrothermal, but some is probably scavenged from sea water by amorphous iron hydroxide floes along with other elements concentrated in hydrothermal sediments, Ni, Cu, and Zn. During the past 50 m.y. all of these elements accumulated over the East Pacific Rise at rates nearly an order of magnitude higher than those at non-rise-crest sites. In addition, factor analysis indicates that some of this material is carried substantial distances to the west of the rise crest. Accumulation rates of Fe in basal metalliferous sediments indicate that the hydrothermal activity that supplied amorphous Fe oxides to the East Pacific Rise areas was most intense during middle Eocene and late Miocene to early Pliocene time.

Geochemistry of Central American Volcanic Arc basement samples

The Central American Volcanic Arc (CAVA) has been the subject of intensive research over the past few years, leading to a variety of distinct models for the origin of CAVA lavas with various source components. We present a new model for the NW Central American Volcanic Arc based on a comprehensive new geochemical data set (major and trace element and Sr-Nd-Pb-Hf-O isotope ratios) of mafic volcanic front (VF), behind the volcanic front (BVF) and back-arc (BA) lava and tephra samples from NW Nicaragua, Honduras, El Salvador and Guatemala. Additionally we present data on subducting Cocos Plate sediments (from DSDP Leg 67 Sites 495 and 499) and igneous oceanic crust (from DSDP Leg 67 Site 495), and Guatemalan (Chortis Block) granitic and metamorphic continental basement. We observe systematic variations in trace element and isotopic compositions both along and across the arc. The data require at least three different endmembers for the volcanism in NW Central America. (1) The NW Nicaragua VF lavas require an endmember with very high Ba/(La, Th) and U/Th, relatively radiogenic Sr, Nd and Hf but unradiogenic Pb and low d18O, reflecting a largely serpentinite-derived fluid/hydrous melt flux from the subducting slab into a depleted N-MORB type of mantle wedge. (2) The Guatemala VF and BVF mafic lavas require an enriched endmember with low Ba/(La, Th), U/Th, high d18O and radiogenic Sr and Pb but unradiogenic Nd and Hf isotope ratios. Correlations of Hf with both Nd and Pb isotopic compositions are not consistent with this endmember being subducted sediments. Granitic samples from the Chiquimula Plutonic Complex in Guatemala have the appropriate isotopic composition to serve as this endmember, but the large amounts of assimilation required to explain the isotope data are not consistent with the basaltic compositions of the volcanic rocks. In addition, mixing regressions on Nd vs. Hf and the Sr and O isotope plots do not go through the data. Therefore, we propose that this endmember could represent pyroxenites in the lithosphere (mantle and possibly lower crust), derived from parental magmas for the plutonic rocks. (3) The Honduras and Caribbean BA lavas define an isotopically depleted endmember (with unradiogenic Sr but radiogenic Nd, Hf and Pb isotope ratios), having OIB-like major and trace element compositions (e.g. low Ba/(La, Th) and U/Th, high La/Yb). This endmember is possibly derived from melting of young, recycled oceanic crust in the asthenosphere upwelling in the back-arc. Mixing between these three endmember types of magmas can explain the observed systematic geochemical variations along and across the NW Central American Arc.

Seismic Hazard and Risk in Central America

1999 Seismic Hazard In Guatemala 2001 Post-Event Mision 2006 Resis Ii Project Norad 2007 Workshop Seismic Hazard 2010 Book Amenaza Sísmica En América Central 2011 Cooperation Haití, República Dominicana, Puerto Rico

Studies of Central American plants. by Paul C. Standley and Julian A. Steyermark.

v.22:no.4(1940)

Central America & Caribbean Region, 1858 (Raster Image)

This layer is a georeferenced raster image of the historic paper map entitled: A new map of tropical-America, north of the Equator : comprising the West-Indies, Central-America, Mexico, New Cranada [sic] and Venezuela by H. Kiepert. It was published by Dietrich Reimer in 1858. Scale [ca. 1:3,600,000].The image inside the map neatline is georeferenced to the surface of the earth and fit to the World Miller Cylindrical projected coordinate system. All map collar and inset information is also available as part of the raster image, including any inset maps, profiles, statistical tables, directories, text, illustrations, index maps, legends, or other information associated with the principal map. This map shows features such as drainage, roads, cities and other human settlements, territorial boundaries and colonial claims, shoreline features, and more. Relief shown by hachures and spot heights. Includes also text and inset map: Central part of the Mexican Republic on an enlarged scale, based upon the surveys published by A. v. Humboldt, v. Gerolt, Heller, Smith and the Sociedad Mejicana de Geografía y Estadística. Scale 1:1,000,000.This layer is part of a selection of digitally scanned and georeferenced historic maps from the Harvard Map Collection. These maps typically portray both natural and manmade features. The selection represents a range of originators, ground condition dates, scales, and map purposes.

CIREFCA : at the crossroads between uprooted people and development in Central America /

Cover title.

The primitive Aryans of America; origin of the Aztecs and kindred tribes, showing their relationship to the Indo-Iranians and the place of the Nauatl or Mexican in the Aryan group of languages,

"Authorities consulted": p. 171-181.

Investment in Central America; basic information for United States businessmen.

Bibliography: p.271-273.

Small farmer credit in Mexico and Central America.

PB 224 025

Immigration from Central America : some thoughts on its causes and cures /

"July 1989."

The old Indian settlements and architectural structures in Northern Central America /

From the Smithsonian Report for 1895, pages 537-555 (with plates XXIX-XXXIV).

The Indian in his wigwam : or, Characteristics of the red race of America ; from original notes and manuscripts /

Originally issued in eight numbers, with paper covers bearing title: Onéota, or The red race of America ... The first four numbers were pub. in 1844, the last four in 1845. Reissued in one volume in 1845 under title: Onéota, or Characteristics of the red race of America ...; in 1847 under title: The red race of America ...; in 1848 under title: The Indian in his wigwam ...; in 1850 and 1851 under title: The American Indians ...; in 1853 under title: Western scenes and reminiscences ... cf. Sabin.

The first book of Indians,

Mode of access: Internet.

Canadian wilds : tells about the Hudson's Bay Company, northern Indians and their modes of hunting, trapping, etc. /

Mode of access: Internet.