Glaciotectonic Processes Associated with the Central Alpine Fault: A Gravity Study of the Central West Coast, South Island, New Zealand

<p>The rugged topographic relief of the central West Coast reflects ongoing interplay between active tectonic and climatic processes. Major geomorphological features have formed in response to convergence between the Pacific and Australian continental plates, and the principal locus of this collision is the transpressive Alpine Fault. This thesis describes a gravity study of glaciotectonic structures in the footwall of the central Alpine Fault and the processes responsible for their formation. During this study 361 new gravity observations were collected in the Wanganui, Whataroa, Waiho, and Fox river flood plains on the western (footwall) side of the Alpine Fault. When combined with existing gravity observations, the available database comprises 932 measurements over the four catchments. These gravity data are used to produce detailed gravity maps and 2-3/4D gravity models of the subsurface structure below the flood plains. Models reveal extensive glacial erosion focused within the flood plains, with individual glacial channels reaching depths of ~ 800 m. Based on fault-perpendicular models, it is proposed that the South Westland Fault is a transition between a thrust-driven monocline structure in South Westland and the steeply dipping Hohonu reverse fault in North Westland. Using gravity data, dextral off sets on the Alpine Fault since the Last Glacial Maximum have been determined by examining the structure and geomorphology of deeply incised glacial erosional channels. By studying how the lower reaches of the Wanganui, Whataroa, and Fox rivers have been translated with respect to their channels on the eastern (hanging wall) side of the Alpine Fault, horizontal fault displacements have been determined in three of the four catchments. Fault offsets of 383 ± 388 m, 372 ± 88 m, and 450 ± 99 m are estimated for the Wanganui, Whataroa, and Fox River valleys respectively. A range of possible channel formation ages are used to estimate dextral strike-slip movement rates, with the preferred formation age of 19 ± 1 ka yielding rates of 20.2 ± 24.0 mm/yr, 19.6 ± 6.0 mm/yr and 23.7 ± 8.5 mm/yr for the Wanganui, Whataroa, and Fox river valleys respectively.</p>

Glaciotectonic Processes Associated with the Central Alpine Fault: A Gravity Study of the Central West Coast, South Island, New Zealand

<p>The rugged topographic relief of the central West Coast reflects ongoing interplay between active tectonic and climatic processes. Major geomorphological features have formed in response to convergence between the Pacific and Australian continental plates, and the principal locus of this collision is the transpressive Alpine Fault. This thesis describes a gravity study of glaciotectonic structures in the footwall of the central Alpine Fault and the processes responsible for their formation. During this study 361 new gravity observations were collected in the Wanganui, Whataroa, Waiho, and Fox river flood plains on the western (footwall) side of the Alpine Fault. When combined with existing gravity observations, the available database comprises 932 measurements over the four catchments. These gravity data are used to produce detailed gravity maps and 2-3/4D gravity models of the subsurface structure below the flood plains. Models reveal extensive glacial erosion focused within the flood plains, with individual glacial channels reaching depths of ~ 800 m. Based on fault-perpendicular models, it is proposed that the South Westland Fault is a transition between a thrust-driven monocline structure in South Westland and the steeply dipping Hohonu reverse fault in North Westland. Using gravity data, dextral off sets on the Alpine Fault since the Last Glacial Maximum have been determined by examining the structure and geomorphology of deeply incised glacial erosional channels. By studying how the lower reaches of the Wanganui, Whataroa, and Fox rivers have been translated with respect to their channels on the eastern (hanging wall) side of the Alpine Fault, horizontal fault displacements have been determined in three of the four catchments. Fault offsets of 383 ± 388 m, 372 ± 88 m, and 450 ± 99 m are estimated for the Wanganui, Whataroa, and Fox River valleys respectively. A range of possible channel formation ages are used to estimate dextral strike-slip movement rates, with the preferred formation age of 19 ± 1 ka yielding rates of 20.2 ± 24.0 mm/yr, 19.6 ± 6.0 mm/yr and 23.7 ± 8.5 mm/yr for the Wanganui, Whataroa, and Fox river valleys respectively.</p>

Assessment of concentration and distribution of total mercury and polychlorinated biphenyls in Green Bay, Wisconsin, USA

Under the 1987 Great Lakes Water Quality Agreement, the lower Green Bay and Fox River estuary have been labeled as areas of concern due to the contamination of mercury and polychlorinated biphenyls (PCBs) from industrialization. These pollutants pose substantial health and environmental hazards for the Green Bay region. The PCBs reported in this region, including Aroclor 1242, are known to trigger carcinogenic responses in animals and mercury targets the central nervous system and vital organs. Furthermore, these compounds are extremely difficult to remove from the environment once introduced. Extensive remedial actions have been implemented including dredging sediments in the Lower Fox River from DePere to Green Bay. The purpose of this study is to assess the concentration and distribution of Aroclor 1242 and total mercury in the Green Bay region sediments and pore waters and to assess the impact of interventions and the natural rates of change previously found.

Analysis of Total Coliform and Total Escherichia coli Levels in the Fox River Watershed

The Fox River is an important water source for the Elgin, IL community. Fecal contaminants must be removed by water treatment facilities to prevent the spread of infectious diseases and to provide potable water. Water samples from the Fox River watershed on or near Judson University campus were tested using the most probable number (MPN) method to determine coliform counts. Our data from this small independent project demonstrates that tap water is free of fecal contaminants and that the Fox River, its tributary Tyler Creek, and the Volkman Retention Pond often have levels of coliforms exceeding standards for recreational use.