Interpretation of seismic profiles, earthquake fault-plane solutions, radar images, and geometry of structures suggests that two different structural styles are viable alternatives for the Putumayo basin in Colombia. An eastern domain, varying in width from 4 to 13 km, might be characterized by strike-slip faulting parallel to the Andes because it exhibits similar structures to those formed in restraining bend settings, an example is the Orito fold, the largest known oil field in the basin. Correlation of seismic reflections with wells into the Orito fold and foreland indicates a post-Miocene age for this structure. Previous interpretations of contractional dip-slip movement on Andes-parallel structures, as proposed by Portilla (1991) with faults involving basement, are also viable. A 15 km-width western domain is interpreted as a region of foreland-dipping rocks uplifted above their regional level by wedging of pre-Cretaceous (?) rocks beneath known Jurassic rocks. Above the Jurassic rocks thin-skinned deformation occurs inside of the Mesozoic and Cenozoic sedimentary cover, also in the form of wedging. Mesozoic and Paleozoic (?) rocks were injected into of a late Cretaceous-early Paleocene unit composed of shale. The western domain is truncated to the west by a major reverse fault that places Paleozoic rocks over Mesozoic and Cenozoic rocks. / text

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This item was digitized as part of the Million Books Project led by Carnegie Mellon University and supported by grants from the National Science Foundation (NSF). Cornell University coordinated the participation of land-grant and agricultural libraries in providing historical agricultural information for the digitization project; the University of Arizona Libraries, the College of Agriculture and Life Sciences, and the Office of Arid Lands Studies collaborated in the selection and provision of material for the digitization project.

The Colorado River is the terrestrial part of a continental scale sediment routing system that has been evolving and carving the landscape of western North America for at least six million years. This study aims to test models of the geological evolution of the Colorado River in particular and the more general drainage history of the SW US. Several possible routes are proposed for the ancestral Colorado River prior to its integration across the Colorado Plateau and incision of the Grand Canyon. Palynological samples from prodelta deposits of the palaeo-Colorado River delta in the Salton Trough produced reworked pollen and dinoflagellate cysts from the river catchment. These provide strong evidence that the Colorado River was fully integrated across the Colorado Plateau during the early Pliocene, supporting heavy mineral data and U-Pb detrital zircon ages. Detrital zircon U-Pb dating provides accurate information for the source of sediment in the basins. Comparison with known ages of zircons in sedimentary units of the Colorado Plateau as well as local basement rocks in the basinal regions has identified two populations of zircons in the deltaic sediments: one from local Mesozoic plutonic basement and a second from Colorado Plateau stratigraphy. The data support recent work on the timing of integration of the river through the Grand Canyon, proving that the 5.33 Ma Colorado River that fed into the Salton Trough was integrated across the Colorado Plateau at that time and that there had already been a degree of incision of the Grand Canyon. A literature review shows how uplift of the Colorado Plateau and development of the San Andreas transform boundary had significant consequences for evolution of the Colorado River. The San Andreas Fault in southern California is responsible for the dextral lateral migration of the Los Angeles Basin and Salton Trough (both on the Pacific Plate) at least from Middle Eocene through Present. The Colorado River, which drains much of the western part of the North American Plate, crossed this major strike-slip plate boundary prior to deposition of the main part of its sedimentary load. The delta of the Colorado is in the v northern Gulf of California at the present day, but palaeo-reconstructions of lateral displacement along the fault show that the Salton Trough lay adjacent to the point where the Colorado River crossed from the North American Plate (at about 5.33 Ma). It is also possible that at about 18 Ma, at the time of fault initiation, the Los Angeles Basin was at the same point. The study uses heavy mineral analysis (HMA) and associated techniques to test the hypothesis that an ancestral Colorado River supplied sediment both to the Los Angeles Basin and the Salton Trough. Analysis of HMA data suggests a broadly similar source for some of the sediment in the two basins, and for the modern river. The data also indicate changes in the catchment area, suggesting that the Colorado River became fully integrated across the Colorado Plateau by the early Pliocene.

Conflictsthattookplacealmostthree centuriesapart – respectivelyinlatemedievalSpainandnineteenth-century South Africa – are described in some detail. The Spanish example offers insight into the effect of the conflictduringtheQonquista,followedbyaperiodofArabruleintheIberianpeninsula,which was terminated by the Reconquista of southern Spain by the Christians. The focus in this regard is the violence and counter violence manifested in the formative stages of the Great Mosque at Córdoba and its transformation into the church of Santa Maria. The behaviour of the Muslims and Christians at the sacred site at Córdoba during the conquest and the reconquest, through many centuries, became a theatre in which conflictingreligiousemotionswerearousedandeventuallyresultedinthepartialdestruction of a magnificentMuslimedifice.WhathappenedatCórdobaisanobjectlessontoallmulticultural societies in which the dominant group avenges itself upon the cultural artefacts of a subjected group. This is a common occurrence in the history of architecture, and fitsthebasicpremiseofRenéGirard’s theory of “mimetic desire” that states that one group desires what another desires. As the envy becomes more intense, “mimetic rivalry” with a model results: admiration is transformed into violent conflictthatisonlydiffusedifascapegoatisfound.InamodificationofGirard’sthesisitispostulatedthat in the end the model – taken to be a building or monument – is most often demolished or vandalised as if serving as the scapegoat for the aggressor’s animosity. In more benign cases desire results in the appropriation of the model, but with modificationstoitsidentity. Alternatively,anew model,coexisting with the original, is created by the vanquished to rival the existing model, as happened at the site of Blood River, Natal. In colonial South Africa a monument was erected in 1947 and a more elaborate version of a combat “laager” inaugurated in 1977 to commemorate the battle which took place there on 16 December 1838 between the Voortrekkers and the Zulus, in which the former were victorious. In response, the Zulus established the Ncome Monument and Museum to the east of the Voortrekkers’ monument, officiallyopenedinNovember1999,whichoffersareinterpretationofthe1838battle,celebrates Zulu culture in general and calls for the development of empathy across the cultural and ethnic divide of the former combatants. Ironically, the layout suggests the historical Zulu combat formation.

published_or_final_version / Chinese / Master / Master of Philosophy

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