abstract: Human land use and land cover change alter key features of the landscape that may favor habitat selection by some species. Lizards are especially sensitive to these alterations because they rely on their external environment for regulating their body temperature. However, because of their diverse life-history traits and strategies, some are able to respond well to disturbance by using their habitat in various ways. To understand how they use their habitat and how human modifications may impact their ability to do this, biologists must identify where they occur and the habitat characteristics on which they depend. Therefore, I used species occupancy modeling to determine (1) whether disturbance predicts the presence of two sympatric congeneric (species of the same genus) lizard species Sceloporus grammicus and S. torquatus, and (2) which habitat characteristics are essential for predicting their occupancy and detection. I focused my study in central Mexico, a region of prevalent land use and land cover change. Here, I conducted visual encounter and habitat surveys at 100 1-hectare sites during the spring of 2019. I measured vegetation and ground cover, average tree diameter, and abundance of refuges. I recorded air temperature, relative humidity, and elevation. I summarized sites as either undisturbed or disturbed, based on the presence of human development. I also summarized sites by ecosystem type, desert or forest, based on vegetation composition (i.e., desert-adapted vs. non-desert-adapted plants), evidence of remnant forest, air temperature, and relative humidity. I found that S. torquatus was more likely to be present in disturbed habitat, whereas S. grammicus was more likely to be present in areas with leaf litter, tree cover, and woody debris. S. torquatus was twice as likely to be detected in forests than deserts, and S. grammicus was more likely to be detected at sites with high elevation and high relative humidity, low temperature, and herbaceous and grass cover. These results emphasize the utility of species occupancy modeling for estimating detection and occupancy in dynamic landscapes. / Dissertation/Thesis / Masters Thesis Biology 2020

京都大学 / 0048 / 新制・課程博士 / 博士(農学) / 甲第22130号 / 農博第2376号 / 新制||農||1073(附属図書館) / 学位論文||R1||N5238(農学部図書室) / 京都大学大学院農学研究科森林科学専攻 / (主査)教授 德地 直子, 教授 北島 薫, 准教授 舘野 隆之輔 / 学位規則第4条第1項該当 / Doctor of Agricultural Science / Kyoto University / DGAM

Volcanic-hosted massive sulfide (VMS) deposits are one of the main sources for zinc, copper, lead, silver and gold in Sweden. The majority of VMS deposits in Sweden are located in the Bergslagen region and the Skellefte district (Fig. 1). The Skellefte district hosts approximately 80 VMS deposits whereas 21 deposits have been mined since 1924 and 6 mines are currently in operation. VMS deposits tend to form more often on the intersection of the normal/reverse and transfer faults since there is an increased conductivity for hydrothermal fluids and increased fluid flow, so a structural interpretation of regional and deposit scale is important for exploration. The alteration patterns and mapped structures observed in the West Maurliden coincide with major structures found in the Skellefte district. Using this data and data from previous authors a general structural evolution of the Maurliden deposit has been constructed which shows the presumed outcome from the early extensional and later compressional stages ongoing in the region. Study of the mineralization shows that there is also the possibility to find mineralized rock within possible low strain blocks which might contain preserved primary textures and structures. A schematic plan view of the structure assemblage in the Skellefte district was established which shows perspective areas for future exploration.

The influence of volcanoes on climate is very often debated, not only in the scientific community. However, the question remains, how much may the volcanic activity contribute to the significant ganges, that could cause a response of environment, which lies in the immediate vicinity. These changes could arise as a response on prolonged exposure of the negative influence, which would last much longer than decades, like it is at present. From this reason the situation in the České středohoří Mountains, where the volcanic activity lasted for several million years during the Paleogene period, is studied. This area is extraordinally rich in deposits of so-called volcanic floras, which accompany the neovolcanic activity. The age of the localities are between late Eocene to late Oligocene and it is a long time enough for recognizing some changes in the floristic composition to help elucidate the given problem.

Microearthquake (< M3.0) swarms occur frequently in volcanic environments, but do not always culminate in an eruption. Such non-eruptive swarms may be caused by stresses induced by magma intrusion, hydrothermal fluid circulation, or regional tectonic processes, such as slow-slip earthquakes. Strandline Lake, located 30 km northeast of Mount Spurr volcano in south-central Alaska, experienced an intense earthquake swarm between August 1996 and August 1998. The Alaska Volcano Observatory (AVO) catalog indicates that a total of 2,999 earthquakes were detected during the swarm period, with a maximum magnitude of Mw 3.1 and a depth range of 0-30 km below sea level (with the majority of catalog hypocenters located between 5-10 km BSL). The cumulative seismic moment of the swarm was 2.03e15 N-m, equivalent to a cumulative magnitude of Mw 4.2. Because of the swarm's distance from the nearest Holocene volcanic vent, seismic monitoring was poor and gas and GPS data do not exist for the swarm period. However, combined waveforms from a dense seismic network on Mount Spurr and from several regional seismic stations allow reanalysis of the swarm earthquakes. I first developed a new 1-D velocity model for the Strandline Lake region by re-picking and inverting precise arrival times for 27 large Strandline Lake earthquakes. The new velocity model reduced the average RMS for these earthquakes from 0.16 to 0.11s, and the average horizontal and vertical location errors from 3.3 to 2.5 km and 4.7 to 3.0 km, respectively. Depths of the 27 earthquakes ranged from 10.5 to 22.1 km with an average depth of 16.6 km. A moderately high b-value of 1.33 was determined for the swarm period, possibly indicative of magmatic activity. However, a similarly high b-value of 1.25 was calculated for the background period. 28 well-constrained fault plane solutions for both swarm and background earthquakes indicate a diverse mixture of strike-slip, dip-slip, and reverse faulting beneath Strandline Lake. Finally, five Interferometric Synthetic Aperture Radar (InSAR) images spanning the swarm period unambiguously show no evidence of surface deformation. While a shallow volcanic intrusion appears to be an unlikely cause of the Strandline Lake swarm based on the new well-constrained earthquake depths and the absence of strong surface deformation, the depth range of 10.5 to 22.1 km BSL for relocated earthquakes and the high degree of FPS heterogeneity for this swarm are similar to an earthquake swarm beneath Lake Tahoe, California in 2003 caused by a deep intrusion near the base of the crust (Smith et al, 2004). This similarity suggests that a deep crustal magmatic intrusion could have occurred beneath the Strandline Lake area in 1996-1998 and may have been responsible for the resulting microearthquake activity.

The lower Mount Rogers Formation (LMRF) is described by Rankin (1993) as a sequence of intercalated metabasalts and volcanogenic sediments with minor metarhyolite. We have chosen to examine the sequence of the LMRF units exposed along Elk Garden Ridge, a high shoulder between the summits of Whitetop Mountain and Mount Rogers in the Mount Rogers National Recreation Area in SW Virginia. This sequence represents an uplifted block of LMRF units enclosed by exposures of Whitetop and Wilburn metarhyolites. In the field, progressive lithologic changes can be observed walking up-section along Elk Garden ridge that are indicative of changes in lava compositions and eruptive environments. From the bottom of the section, massive basalts with distinctive 1-2 cm long swallowtail plagioclase phenocrysts grade into vesicular basalts, then into sheet flow basalts, followed by a thick sequence of aphyric and amygdaloidal pillow basalts. Further up section, eruptive products transition into rhyolitic ignimbrites and ash and lapilli tuffs. Boulders of cobble conglomerates near the middle of the sequence and sedimentary layers in between individual sheet flows suggest short periods of relative eruptive quiescence. The only unit broken out in the LMRF by Rankin (1993), Fees Rhyolite, is not observed in the field area, suggesting local differences in topography, eruptive products and eruptive styles across the outcrop area during the deposition of these eruptive products. Petrographically, the rocks reflect the regional greenschist facies metamorphic conditions with chlorite and epidote as primary metamorphic minerals, and unakite-like zones of mineralization. Relict plagioclase and pyroxene phenocrysts persist, as do primary igneous textures and structures. Compositionally, all of the rocks in the Elk Garden Ridge sequence are strongly enriched in alkali metals, with elevated Na2O and K2O contents, and high TiO2 in the basalts. Major and trace element systematics suggest that the chemical signatures of the metabasalts are primary controlled by shallow-level crystallization processes. The LMRF metabasalts share many compositional affinities with later (~570 Ma) rift-related basalts preserved in the Appalachians, suggesting that all of these lavas were formed by melting of a compositionally uniform mantle source, followed by shallow crystallization, despite being separated from one another by large stretches of time and space.

No description available.

More than two million people in the Chaco-Pampean plain in central Argentina are affected by high As levels in groundwater. The concentrations of As are far exceeding the WHO standard limit for safe drinking water of 0.1 μg/L and the provisional Argentinean limit of 0.5 μg/L. The NE of La Pampa province is one of the areas affected with geogenic As in shallow aquifers within the Chaco-Pampean plain. These aquifers are in closed basins and they are only available water resource of the region for drinking and agriculture purposes. The Pampean aquifer is composed of a multi-layered system of Quaternary loess deposits covered by aeolian sands and also containing layers of rhyolitic volcanic ash, which is considered the primary source of As. Volcanic ash layers can be visible in the shallow sediments or intermixed in the loess. During the weathering of volcanic ash sediments As is dissolved to the aqueous phase and can be quickly adsorbed or co-precipitated on secondary Fe, Al and Mn oxy-hydroxides under favourable conditions. Also, previous more arid climatic conditions have led to the formation of carbonate "calcrete" layers in the top sequences of the loess and this has affected the geochemistry of the aquifer. Two sites were investigated in the NE of La Pampa province in order to assess (i) the quality of groundwater for drinking water use, (ii) the distribution of As and other trace elements in shallow aquifers and (iii) to understand better the factors controlling its mobility in groundwater. The results showed that groundwater was circum-neutral to alkaline and under moderate oxidizing conditions. The predominant groundwater composition was of Na-HCO3 for fresh water and Na-Cl-SO42- for brackish water types. High salinity levels are evidenced by the high Electrical Conductivity and might be explained by to the high evaporation rates. Groundwater sampled in both areas was enriched with As, F and other trace elements at different ranges of concentration. From the total As concentrations, arsenate As(V) predominated over arsenite As(III) species. Shallow groundwater is also enriched with fluoride exceeding the WHO standard limit of 1.5 mg/L and placed in the same As hotspots. One possible factor controlling the mobility of As is the high pH of groundwater, which is controlled by the carbonates equilibrium. Under this high pH conditions As is less strongly bind to Fe, Al and Mn oxy-hydroxides and can be easily mobilized to groundwater when other competing ions are getting adsorbed on the surface sites of binding minerals.

In this thesis, the results from a geophysical mapping and coring campaign of Lagoa das Furnas are presented. Specific focus is placed on the origin of a subaqueous volcanic cone mapped in the southern part of the lake. Lagoa das Furnas is a crater lake within the Furnas volcanic centre which is located on the island of São Miguel in the Azores archipelago. The Furnas volcanic centre has a long history of earthquakes and volcanic activity. The area is relatively well-studied, except for the lake floor. Therefore, a high resolution geophysical and geological mapping survey was conducted at Lagoa das Furnas. Sidescan sonar was used to map the surface of the lake floor and single beam sonar was used to acquire sub-bottom profiles. In addition to the geophysical mapping, sediment surface sampling and core drilling were carried out followed by geochemical analyses of the retrieved material. The mapped data permitted a characterisation of the floor of Lagoa das Furnas and revealed several volcanic features including fumarole activity and a volcanic cone in the southern part of the lake. In order to unravel the origin of this cone several methods were applied, including analyses of tephra and minerals collected from the cone itself and from nearby deposits of two known eruptions Furnas I and Furnas 1630. Sedimentological, petrological, geochemical and geochronological studies of pyroclastic deposits from the cone suggest a subaqueous eruption linked to the Furnas 1630 eruption. The chemistry of glass and crystal fragments sampled from the cone suggests that it is composed of more evolved magma than that of the main Furnas 1630 implying that the lake cone is likely a product of the last eruptional phase. Historical documents reveal three lakes in Furnas valley before the 1630 eruption. Two of these lakes were lost due the eruption and the remaining lake is most likely Lagoa das Furnas and consequently did exist before the 1630 eruption.

京都大学 / 新制・課程博士 / 博士(地球環境学) / 甲第23352号 / 地環博第210号 / 新制||地環||40(附属図書館) / 京都大学大学院地球環境学舎地球環境学専攻 / (主査)教授 舟川 晋也, 教授 德地 直子, 准教授 渡邉 哲弘 / 学位規則第4条第1項該当 / Doctor of Global Environmental Studies / Kyoto University / DFAM