Este estudo teve como objetivo principal a definição da origem, evolução, geometria e preenchimento do Complexo de Canyons de Brejo Grande. Este complexo está incluído no intervalo maastrichtiano do Grupo Piaçabuçu, que é composto por uma cunha sedimentar progradante, depositada num sistema plataforma-talude-bacia, do Cretáceo Superior ao Quaternário, na Bacia de Sergipe-Alagoas. Foram utilizados dados sísmicos, perfis de poços, dados bioestratigráficos e descrições de testemunhos e amostras de calha. O complexo é composto de três canyons: Canyon de Brejo Grande, o mais antigo; Canyon do Rio Praúnas e Canyon de Aroeira, o mais novo. A localização e orientação dos canyons foram controladas por falhas da fase rift, reativadas antes da escavação. Foram reconhecidas quatro fases de preenchimento: fase inicial, fase de by-pass, fase dos complexos de canais e fase da cunha progradante. Na fase inicial, foram depositados os complexos de transporte de massa. Eles estão melhor preservados quando preenchem calhas na base do canyon. Na fase de by-pass o canyon atuou como um conduto e apenas depósitos de lags foram preservados. A fase dos complexos de canais ocorreu quando os fluxos gravitacionais não mais transportavam suas cargas para a bacia e depositavam a maior parte de sua carga dentro do canyon. A fase da cunha progradante corresponde à parte do preenchimento depositada no começo da subida do nível relativo do mar. Os complexos de canais são os componentes mais importantes do preenchimento dos canyons. Seus canais são frequentemente isolados espacialmente. Eventos sísmicos anômalos produzidos pelos canais mostram que eles são estreitos, com baixa sinuosidade e continuidade longitudinal variável. Os canais empilham-se verticalmente na parte inferior, mais confinada, do preenchimento dos canyons, e lateralmente na parte superior, menos confinada, dos canyons assimétricos. Os canais migram das partes mais confinadas para as menos confinadas. O método da estratigrafia de seqüências foi usado para estabelecer a evolução do complexo de canyons, definindo as seqüências que os preencheram, as relações de tempo entre aorigem e o preenchimento dos canyons e as superfícies limitantes e internas das seqüências. Foram definidas três seqüências de 3ª ordem. Cada canyon foi preenchido por uma seqüência deposicional composta pelos tratos de sistemas de mar baixo e transgressivo. Nos tratos de mar baixo das seqüências 1,2 e 3 foram identificados o equivalente proximal do leque de fundo de bacia e o complexo de canais do leque de talude. Na seqüência 3, além destes, foi também observada a cunha progradante. O limite inferior da seqüência 1 corresponde à base da biozona de nanofósseis N-280. O limite inferior da seqüência 2 coincide com a base da biozona de nanofósseis N-290. / Canyon The channels stack vertically in the lower, more confined portion of canyons, and laterally in the upper, less confined part of asymmetric canyons. Lateral migration of channels is from the side of steeper to the side of less steep wall, where confinement is smaller. The sequence stratigraphy method was used to establish the evolution of the canyon complex, defining the sequences that filled the canyons and the time relationship between the origin and filling of canyons and the boundary and internal surfaces of sequences. Three third order depositional sequences were defined. Each canyon is filled by a depositional sequence compounded of lowstand and transgressive system tracts. In the lowstand system tracts of the first, second and third sequences were identified a proximal equivalent of the basin floor fan andthe channel complexes of the slope fan. In the third sequence, besides those parts, was also observed the progradational wedge. The inferior limit of the first sequence corresponds to the N- 280 nannofossil biozone base and the inferior limit of the second sequence coincides with the N- 290 nannofossil biozone base.

Este estudo teve como objetivo principal a definição da origem, evolução, geometria e preenchimento do Complexo de Canyons de Brejo Grande. Este complexo está incluído no intervalo maastrichtiano do Grupo Piaçabuçu, que é composto por uma cunha sedimentar progradante, depositada num sistema plataforma-talude-bacia, do Cretáceo Superior ao Quaternário, na Bacia de Sergipe-Alagoas. Foram utilizados dados sísmicos, perfis de poços, dados bioestratigráficos e descrições de testemunhos e amostras de calha. O complexo é composto de três canyons: Canyon de Brejo Grande, o mais antigo; Canyon do Rio Praúnas e Canyon de Aroeira, o mais novo. A localização e orientação dos canyons foram controladas por falhas da fase rift, reativadas antes da escavação. Foram reconhecidas quatro fases de preenchimento: fase inicial, fase de by-pass, fase dos complexos de canais e fase da cunha progradante. Na fase inicial, foram depositados os complexos de transporte de massa. Eles estão melhor preservados quando preenchem calhas na base do canyon. Na fase de by-pass o canyon atuou como um conduto e apenas depósitos de lags foram preservados. A fase dos complexos de canais ocorreu quando os fluxos gravitacionais não mais transportavam suas cargas para a bacia e depositavam a maior parte de sua carga dentro do canyon. A fase da cunha progradante corresponde à parte do preenchimento depositada no começo da subida do nível relativo do mar. Os complexos de canais são os componentes mais importantes do preenchimento dos canyons. Seus canais são frequentemente isolados espacialmente. Eventos sísmicos anômalos produzidos pelos canais mostram que eles são estreitos, com baixa sinuosidade e continuidade longitudinal variável. Os canais empilham-se verticalmente na parte inferior, mais confinada, do preenchimento dos canyons, e lateralmente na parte superior, menos confinada, dos canyons assimétricos. Os canais migram das partes mais confinadas para as menos confinadas. O método da estratigrafia de seqüências foi usado para estabelecer a evolução do complexo de canyons, definindo as seqüências que os preencheram, as relações de tempo entre aorigem e o preenchimento dos canyons e as superfícies limitantes e internas das seqüências. Foram definidas três seqüências de 3ª ordem. Cada canyon foi preenchido por uma seqüência deposicional composta pelos tratos de sistemas de mar baixo e transgressivo. Nos tratos de mar baixo das seqüências 1,2 e 3 foram identificados o equivalente proximal do leque de fundo de bacia e o complexo de canais do leque de talude. Na seqüência 3, além destes, foi também observada a cunha progradante. O limite inferior da seqüência 1 corresponde à base da biozona de nanofósseis N-280. O limite inferior da seqüência 2 coincide com a base da biozona de nanofósseis N-290. / Canyon The channels stack vertically in the lower, more confined portion of canyons, and laterally in the upper, less confined part of asymmetric canyons. Lateral migration of channels is from the side of steeper to the side of less steep wall, where confinement is smaller. The sequence stratigraphy method was used to establish the evolution of the canyon complex, defining the sequences that filled the canyons and the time relationship between the origin and filling of canyons and the boundary and internal surfaces of sequences. Three third order depositional sequences were defined. Each canyon is filled by a depositional sequence compounded of lowstand and transgressive system tracts. In the lowstand system tracts of the first, second and third sequences were identified a proximal equivalent of the basin floor fan andthe channel complexes of the slope fan. In the third sequence, besides those parts, was also observed the progradational wedge. The inferior limit of the first sequence corresponds to the N- 280 nannofossil biozone base and the inferior limit of the second sequence coincides with the N- 290 nannofossil biozone base.

No description available.

The purpose of this thesis was to gain an insight into the macrobotanical subsistence practices of Nancy Patterson Village and see how those practices fit in with the practices of the general Mesa Verde region by analyzing the burnt macrobotanical remains found in processed flotation samples. Previous work done at Nancy Patterson Village showed a shift in the faunal subsistence practices to a greater reliance on domesticated turkey during the Pueblo III period. However, the macro botanical analysis showed a higher richness of wild plant taxa in the Pueblo III period when compared to Pueblo II. The change to a higher richness of plant taxa in the later period is attributed to the changes in social and environmental climates causing difficulties in sustaining the population. These difficulties pushed the inhabitants to expand their selection of plant types used for food. Despite the higher richness of plant taxa in Pueblo III, other sites from the Central Mesa Verde region had higher richness. However, Nancy Patterson Village used the smaller number of wild plants types more intensely than the other sites from the region. No explanation was found to explain this difference.

The results of an archaeological survey of North Cottonwood Canyon, San Juan County, southeastern Utah, are herein reported. The purpose and background leading up to the survey are followed by a physical description of the canyon and a description of the 36 archaeological sites recorded. The cultural material collected and/or observed at the sites, including architecture, ceramics, and other miscellaneous artifacts, is described and discussed. This is followed by a distributional analysis between sites. This includes altitude, slope, water resources, and vegetation. Cultural materials in North Cottonwood Canyon are then compared with materials from related areas, including Montezuma Canyon, Beef Basin, Salt Creek, Indian Creek, Cedar Mesa, Hammond Canyon, and Glen Canyon. This is followed by the Conclusion, which discusses the time periods the canyon was inhabited, the lifeway of the prehistoric inhabitants, and some possibilities for further work that hopefully will be conducted in the canyon at a future date.

Snow accumulation and melt characteristics were studied in Logan Canyon, Utah. Three replications of aspen, conifer, and open field types at 6300, 7100,and 8000 feet were measured for snow depth and water content during 1972. Elevation was found to have the greatest effect on snow water content. The gradient of increasing water content with rise ln elevation was found to be .51 inches/100 feet in the zone from 6300 to 7100 feet and 1.9 inches/100 feet from 7100 to 8000 feet. The cooler temperatures at higher elevations partially account for the 8000 foot zone beginning to melt 40 days after the 7100 foot zone, and the 7100 foot zone trailing the 6300 foot zone by 20 days. Although the snow at the 8000 foot elevation began melting later than the lower zones, it melted at twice the rate. Vegetation cover type has no significant effect on the amount of snow deposited. However, the conifer type protects the snowpack from solar radiation causing the snowpack to have a significantly lower density than the snowpack assocaited with either aspen or open field. The snowpack under the conifer canopy melts 30 percent slower and remains 17 days longer.

Studies of environmental and riparian vegetation interrelationships along the lower Escalante River were conducted during 1974 and 1975. The study area included the Escalante River flood terrace between Harris Wash and Coyote Gulch. Methods were developed compatible for wilderness use . Sixty nine 1 x 10 meter macro-plots were taken at 23 locations. Measurements were taken of major environmental parameters thought to influence riparian vegetation : stratigraphy, soil texture and moisture, river bank angle and aspect, and height and width of flood terraces. Canyon profile was found to be strongly influenced by geologic strata. Resistance to erosion by these strata determines canyon fluctuations and flash floods further modify the river bank profile by creating three distinct flood terraces. Vegetation distribution was found to be generally correlated with stratigraphy and flood terraces. The most dominant semi-aquatic species, Scirpus americanus and Eguisetum laevigatum were found on soils saturated to supersaturated with water on the low flood terraces. Baccharis emoryi was found in the medium and high flood terraces where the Chinle Formation was exposed. Different time periods between river inundations and flash floods created significantly different population age structures for the three major tree species (Salix exigua, Populus fremontii, and Tamarix pentandra). Tree longevity increased from low to high flood terraces. Population age structure differences were attributed to flooding which dynamically maintains each cohort. Regeneration by root suckers for Salix and Populus have survival rates greater than Tamarix whose seedling source is washed away by periodic fluctuations in river level. Implications of this research are that reduction in river flow or regulation of floods would remove population equilibrium controls. Tamarix, without the effec t of its seed source being washed away , would have a successional advantage over the other two native tree species whose densities in the young age classes are lower than that of Tamarix. Furthermore, tree populations would shift to an older age structure with greater density. Deleterious effects would be increased evapotranspiration and inaccessability to river recreation. The effects of such vegetation changes on wildlife are unknown.

In 1899, Robert T. Hill led the first scientific exploration of the remote segment of the Rio Grande known as the Big Bend. Hill’s observations from this expedition were published in an article titled “Running the Cañons of the Rio Grande.” At the time of Hill’s expedition, the stream flow of the Rio Grande was largely depleted by water development in the upstream portions of the basin. The continued overallocation of the Rio Grande has led to the degradation of aquatic ecosystems in the Big Bend, one of North America’s largest transboundary protected areas, such that management of natural resources in this region is a high priority. Many of the native species in this region are listed as threatened or endangered due to habitat loss, which is driven by channel narrowing. Thus, excess fine sediment, along with invasive riparian species, has been identified as negatively impacting ecological resources in the Big Bend and studies recommend increased stream flow as the most effective tool for managing excess fine sediment. Aside from historical accounts, there was previously no estimate of the Rio Grande’s natural flow regime nor an adequate understanding of how the role of characteristic floods in the Big Bend shaped the pre-disturbance channel. In the following two studies, we fill in these crucial knowledge gaps by estimating the pre-disturbance flow regime of the Rio Grande, describing how channel narrowing is not spatially uniform in the Big Bend, and analyzing past floods to determine the role of past flood regimes in shaping alluvial deposits that contribute to channel narrowing.

This study compares insect and cattle consumption of crested wheatgrass (Agropycon spp.) on a site in Sterling Ranch, Utah County, Utah. The hypothesis tested is that insect consumption in general, and specifically consumption by Labops hesperius Uhler, significantly reduces total available cattle forage. Labops and grasshoppers were probably the major cause of secondary damage at the study site, while the impact of thrips is unknown. A detrimental impact on range was suggested by the data, as insects consumed forage equivalent to 2.8 animal units per month, while cattle consumed forage equivalent to 2.1 animal units per month at the study site. Based on a grazing fee of $1.60 per animal unit per month, this represents a loss of $3.50 per acre. Although a low level Labops population was present at the time of the study, potential exists for this population to reach higher level s that would cause much higher levels of damage. Crested wheatgrass, the major vegetation at the study site, is capable of resuming growth in the fall if there is sufficient moisture. Because there is only one generation of Labops per year, fall herbage production would not suffer Labops damage, but may suffer damage by other insects that are present in the fall.

The wild lands recreational resources of the canyon country of southeastern Utah were analyzed within an evaluation framework specific to the region. Patterns of recreation development were established and recommendations for planning were submitted. The study area was found to be richly endowed with environmental recreation resources and opportunities. Contributing environmental factors included the uniqueness, diversity, configuration, and/or abundance of the scenic, water, climatic, and primitive resources. An unusually wide spectrum quality opportunities were present. Planning and development were inconsistent with the expression of the environmental resources. A lack of coordination among the responsible public agencies, disparities in allocation of planning and development priorities, and the failure of planning to derive maximum utility from the resources were evident. Deficiencies of existing development can be easily corrected because of the embryonic state of development. Recommendations pertinent to coordination among agencies, master planning, facilities development, land classification, wilderness allocation, interpretation, and scenic drives were proposed.