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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

A GIS-based inventory of terrestrial caves in West Central Florida: Implications on sensitivity, disturbance, ownership and management priority

Harley, Grant L 01 June 2007 (has links)
Active cave management, which represents any continuous action to conserve, restore, or protect a cave environment, is virtually non-existent in west-central Florida. This study focuses on developing an inventory to rank terrestrial caves in west-central Florida by management priority. A GIS-based cave inventory system, including a cave sensitivity index and cave disturbance index, were used as a tool to gain an understanding of the management priority of west-central Florida caves. The inventory was applied to 36 terrestrial caves in west-central Florida, which demonstrated a wide range of sensitivity and disturbance. The results show that by relying solely on sensitivity and disturbance scores, management priority may not be accurately determined. Further examination revealed that ownership and management status also affect management priority. Consequently, cave sensitivity, disturbance, ownership, or management status does not solely indicate management priority. Rather, the management priority of caves in west-central Florida depends on a number of complicated, interwoven factors, and the goal of management must be examined holistically. Each cave must be individually examined for its sensitivity, disturbance, resources, management, and social and physical context in order to gain an understanding of management priority. Nonetheless, the cave inventory system developed for this project was used to gain a general understanding of which caves hold management priority, based on the cave manager's objectives. In order to ensure the conservation and protection of west-central Florida terrestrial caves, support from county or state government, combined with cave inventory data, is crucial in developing sound management policy.
2

An Age-Depth Model and Revised Stratigraphy of Vertebrate-Bearing Units in Natural Trap Cave, Wyoming

Lovelace, David M., Redman, Cory M., Minckley, Thomas A., Schubert, Blaine W., Mahan, Shannon, Wood, John R., McGuire, Jenny L., Laden, Juan, Bitterman, Kathleen, Heiniger, Holly, Fenderson, Lindsey, Cooper, Alan, Mitchell, Kieren J., Meachen, Julie A. 01 January 2022 (has links)
Excavations at Natural Trap Cave (NTC) began in the mid-1970's and quickly yielded evidence of a diverse steppe fauna that existed during the Last Glacial Maximum (MIS 2) along the western slope of the Bighorn Mountains in north central Wyoming. NTC is a karst pit cave with a 24.5 m vertical drop into a roughly 43 m wide bell-shaped ‘Main Chamber’ and during the course of early excavations a plugged entrance to a fossil-bearing ‘Lower Chamber’ was discovered. Stratigraphic relationships below the entrance to the Main Chamber of the cave were originally studied in the mid-1970's, but were never formally published. Although stratigraphy, taphonomy, and depositional circumstances were briefly discussed over the following years, little has been done to correlate the numerous stratigraphic schemes used by various authors. In this study, four stratigraphic sections were measured and analyzed to establish an easily modifiable lithostratigraphic system of nomenclature. We provide the first correlations of all stratigraphic nomenclature used throughout excavations at NTC to facilitate comparisons with current and previous collections and publications. By leveraging more than 100 radioisotopic dates we developed an age-depth model and chronostratigraphic framework to further interrogate spatiotemporal relationships between strata, paleoenvironmental proxies, and fossil assemblages. Deposition is shown to be discontinuous; sediment accumulation in the study area is restricted to the buildup through peak penultimate and Last Glacial maxima. More recent (<10 ka) Holocene deposits unconformably cover the eroded surface of underlying Pleistocene strata. There is active reworking of sediments with transport and deposition of reactivated material within the Lower Chamber. We note that the two hiatuses coincide with interglacial periods and may reflect changing depositional circumstances within the cave such as extended periods of non-deposition, erosion, or bypass (possibly leading to deposition in the Lower Chamber). Contrary to previous reports, we demonstrate that it is unlikely a prominent snow cone existed or contributed to the pattern of sediment and fossil distribution within the study area, furthermore, we do not observe a continuous Pleistocene-Holocene transition in the study area. Further stratigraphic work will be needed to better understand the interrelationship between Main and Lower chamber deposits and the evolution of sediment accumulation in NTC.
3

Comparing Structure from Motion Photogrammetry and Computer Vision for Low-Cost 3D Cave Mapping: Tipton-Haynes Cave, Tennessee

Elmore, Clinton 01 August 2019 (has links)
Natural caves represent one of the most difficult environments to map with modern 3D technologies. In this study I tested two relatively new methods for 3D mapping in Tipton-Haynes Cave near Johnson City, Tennessee: Structure from Motion Photogrammetry and Computer Vision using Tango, an RGB-D (Red Green Blue and Depth) technology. Many different aspects of these two methods were analyzed with respect to the needs of average cave explorers. Major considerations were cost, time, accuracy, durability, simplicity, lighting setup, and drift. The 3D maps were compared to a conventional cave map drafted with measurements from a modern digital survey instrument called the DistoX2, a clinometer, and a measuring tape. Both 3D mapping methods worked, but photogrammetry proved to be too time consuming and laborious for capturing more than a few meters of passage. RGB-D was faster, more accurate, and showed promise for the future of low-cost 3D cave mapping.

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