14C Age of Glaciation in Estrecho de Magallanes–Bahía Inútil, Chile
Author
Heusser, C. J.Issue Date
1999-01-01Keywords
Bahia Inutil ChileEstrecho de Magallanes Chile
Magallanes Chile
Puerto del Hambre
reworking
Chile
age
accuracy
South America
Holocene
paleoclimatology
Pleistocene
glaciation
Cenozoic
Quaternary
C 14
carbon
dates
isotopes
radioactive isotopes
absolute age
Metadata
Show full item recordCitation
Heusser, C. J. (1999). 14C age of glaciation in Estrecho de Magallanes–Bahía Inútil, Chile. Radiocarbon, 41(3), 287-293.Journal
RadiocarbonAdditional Links
http://radiocarbon.webhost.uits.arizona.edu/Abstract
Basal 14C dates from a core of the mire at Puerto del Hambre (53 degrees 36'21"S, 70 degrees 55'53"W), located within the area of glaciation in Estrecho de Magallanes-Bahia Inutil, Chile, are no older than 14,455 +/115 yr BP. The 14C dates are on samples from which screening isolated autochthonous plant remains. Previous 14C dates of 15,800 +/200, 16,590 +/320, and 16,290 +/140 yr BP are from bulk samples collected from similar basal increments at the site during 3 separate, independent coring operations. The previous suite of 14C dates was suspected to be contaminated by older carbon in the light of chronological evidence, which indicates a 14C age of approximately 14,850 yr BP for glaciation elsewhere in southern Chile. Contamination by "infinitely old" carbon reworked from nearby Tertiary beds and redeposited at Puerto del Hambre is evidently the cause for the older 14C dates.Type
Articletext
Language
enISSN
0033-8222ae974a485f413a2113503eed53cd6c53
10.1017/S0033822200057143
Scopus Count
Collections
Related items
Showing items related by title, author, creator and subject.
-
Application of snow distribution models within the laguna Negra basin, ChileCadle, Brad J.; Bales, Roger C.; Department of Hydrology & Water Resources, The University of Arizona (Department of Hydrology and Water Resources, University of Arizona (Tucson, AZ), 1997-08)Spectral linear unmixing and binary regression trees were used to estimate the distribution of snow within the Laguna Negra basin in Chile. Spectral linear unmixing was performed for multi-band Landsat 5 images for the determination of sub-pixel snow fractions. We were interested in determining the number of bands needed for an adequate distribution of SCA. Results showed that for winter scenes (scenes with greater than 90% snow cover and portions of the basin covered by shadows) linear spectral unmixing can be used to model SCA using at least four bands with a rock, a snow and a shaded snow endmember, but that five bands, using two rock endmembers, a snow and a shaded rock endmember, are needed for the fall scenes (scenes with less than 10% snow cover and portions of the basin covered by shadows). The spring scenes (scenes with 50 percent and higher snow cover and no shadows) showed plausible results with three bands, but the need for a second rock endmember in the fall scenes suggest 4 bands may give a more accurate result. A binary regression tree model was used to determine distributed SWE at peak accumulation in the Echaurren basin, a sub basin of Laguna Negra. Regression trees grown from field snow survey data did an excellent job at explaining the variation of SWE in two of the three surveys examined when resubstitution was used to evaluate the model, but did a poor job in all cases when cross validation was used. However, cross validation may over estimate the errors associated with the model. Basin-wide SWE maps resulting from the application of the regression trees formed plausible structures. Normalized snow distribution was sufficiently different between years such that a "typical" SWE map could not be developed. Nonetheless, there were identifiable patterns that did occur in the SWE distributions from different years that gave insight into the factors affecting SWE in the basin. Such factors include a strong dependance on radiation in the lower portion of Echaurren for two of the years, and the presence of heavy SWE regions near cliffs. Insights such as these provided useful information on how the type of data and method of collection might be improved. The large SWE values near cliffs, for instance, suggest that use of an avalanche map might improve the modeled SWE distribution. The dependance of SWE on radiation in the lower basin suggest the SWE data should be obtained over the entire range of radiation values in the lower basin.
-
Effect of Messenger® on Chile Pepper Production and Bacterial Spot in 2001Matheron, Michael E.; Porchas, Martin; Byrne, David N.; Baciewicz, Patti (College of Agriculture and Life Sciences, University of Arizona (Tucson, AZ), 2002-08)Messenger is based on naturally occurring proteins called harpins that trigger natural plant defense systems to protect against disease and pest damage as well as activating plant growth pathways for potential improvements in crop yield and quality. An experiment was established in a commercial chile pepper field in Cochise County to evaluate the effect of Messenger on chile pepper production and bacterial spot. Bacterial spot of pepper occurs wherever this crop is exposed to moisture due to rainfall or overhead irrigation. Foliar application of Messenger, Kocide 2000 + Maneb 75DF (a standard bacterial spot treatment) or Messenger + Kocide + Maneb was performed June 5, 19 and 28; July 16; and August 8 and 22. A foliar defoliation (bacterial spot) rating was performed September 5 and yield (weight and number of chile peppers) was determined September 20 and 21. Compared to nontreated plants, the mean weight of chile peppers harvested from plants treated with Messenger, Kocide + Maneb and Messenger + Kocide + Maneb increased 11, 15 and 24%, respectively, whereas the number of peppers increased 14, 15 and 21%, respectively. The severity of bacterial spot symptoms was numerically (but not significantly) lower on plants treated with Messenger, Kocide + Maneb and Messenger + Kocide + Maneb compared to nontreated plants.
-
Deconstructing hegemony: The state/labor partial regime in ChileBuchanan, Paul G.; Putnam, Elizabeth Mary, 1955- (The University of Arizona., 1992)Hegemony is viewed through the lens of the state-labor partial regime in post-authoritarian Chile. A review of the hegemonic "debate" reveals that agricultural labor was excluded from labor incorporation in 1932. Rural labor's subsequent superexploitation subsidized industrial workers with cheap production of wage goods. Agricultural workers' incorporation in the mid-1960s unified the workforce and initiated the organic crisis that intensified with the election of a Socialist executive. The dictatorship that overthrew Allende disarticulated all forms of collective action. Its coercive foundation and neo-liberal economic project forced a retreat from collective to individual strategies. The current regime is left with hierarchical state/labor relations wrapped around a core of atomizational pluralism. Inclusionary pluralist labor reforms simultaneously fulfill ideological bases of consent and obstruct the working class unity needed to achieve substantive gains. On this foundation of individualism, a bourgeois hegemonic project (safe from collective counter-hegemonic threat) is being constructed to protect the rule of capital.