Keiminės terasos Lietuvos teritorijoje yra aptinkamos Vėlyvojo Nemuno apledėjimo Baltijos stadijos ledyno paliktame reljefe. Pagrindinis šio darbo tikslas – Vėlyvojo Nemuno apledėjimo srityje esančių keiminių terasų paplitimo, jų morfologijos, sandaros, kilmės ir padėties ištyrimas. Ankstesnėse publikacijose buvo tik konstatuojama keiminių terasų geomorfologinė padėtis ir aprašomi morfologiniai terasų požymiai. Pagrindiniu tyrimo metodu pasirinktas kartografinis. Keiminės terasos yra savarankiški ledyno pakraštiniai dariniai, susidarę tarp reljefo formų, susiformavusių supraglacialinėje ir terminoglacialinėje subaplinkose. Ledyno ledo dangos šlaitas buvo tik viena iš jas sudarančių nuogulų sedimentacinės erdvės ribų. Terasų vidinė sandara tiesiogiai priklauso nuo ją formavusių veiksnių. Pagal tai skiriamos fliuvioglacialinės, limnoglacialinės ir mišrios akvaglacialinės keiminės terasos. Darbe pateikta klasifikacija paremta keiminių terasų Lietuvos teritorijoje morfologijos, morfometrijos ir sandaros tyrimais. Atlikti tyrimai svarbūs fundamentiniu aspektu, nes nustatyta skirtingų keiminių terasų tipų morfogenezė, sandara ir susidarymo paleogeografinės sąlygos, degraduojant Vėlyvojo Nemuno apledėjimo ledynui, gali būti panaudota kituose regionuose sprendžiant analogiškų formų susidarymo klausimus. Darbą sudaro 167 psl., 88 paveikslai, 1 lentelė. Literatūros sąraše 173 bibliografiniai pavadinimai. / Kame terraces in the territory of Lithuania are found in the Late Nemunas glaciation Baltija stage relief. Investigation of the distribution, morphology, composition, origin and position of kame terraces in the Late Nemunas glaciation area is the main objective of the present study. The previous publications merely contained statements about the geomorphological position of kame terraces and descriptions of morphological features of terraces. The research was carried out by cartographic method. Kame terraces are isolated glacier marginal formations deposited between the landforms that formed in supraglacial and terminoglacial environments. The ice slope of a decaying glacier only represented one of the boundaries of sedimentation space. The structure of terraces was directly affected by the forming factors. According to the forming factors, kame terraces are classified as glaciofluvial, glaciolacustrine and mixed aquaglacial. The presented classification is based on the studies of morphology, morphometry and structure of kame terraces in the territory of Lithuania. The conducted study has a fundamental value since the established morphogenesis, structure and palaeogeographical conditions of formation of different types of kame terraces, created by the decaying Late Nemunas glacier, can be used for solution of the formation issues of similar forms in other regions. The dissertation is comprised of 167 pages, 88 illustrations and one table. The list of references has 173... [to full text]

Four prograding reef terraces (6, 15, 30, and 50 m) have been repetitively exposed to marine and freshwater alteration during the Pliocene and Pleistocene periods. Prolonged freshwater alterations have resulted in many diagenetic overprints that obscure early diagenetic products. This study investigates the sequence of the diagenetic processes and products in the terrace deposits using five long cores and 14 short cores taken from these different reef terraces. The lithologic changes in the cores were documented for reconstruction of the original depositional frameworks prior to embarking on a diagenetic study. Both textural and geochemical changes were examined within all four different terraces in order to characterized the diagenetic history. The textural changes observed in the cores and thin sections, provided preliminary evidence of the diagenetic environment. Through the use of X-ray diffractometry, stable isotopes (C and O), and trace element data, the interpretation of the diagenetic environment can be constrained. The reef terraces were deposited as as shallowing upward units following a down-stepping carbonate sequence. The lithology of the cores is dominated by reefal facies, which consist of the back reef, reef crest, front, and fore reef facies. The exposure surfaces, observed at various depths, constrained the interpretation of early diagenetic environments (met. vadose and phreatic). Three major diagenetic environments can be characterized from the cores, these are meteoric vadose, meteoric phreatic, and dolomitizaton. These diagenetis environments produced different geochemical signatures, which can be quantified through analysis of the stable isotopes and trace elements incorporated into the cements. The different reef terraces represent different duration of exposure, with the higher terraces having been exposed longer than the lower ones. This study enables the documentation and comparison of the processes and products of the meteoric diagenesis that occurred within these different terraces. In addition, this study also constrain the early dolomitization observed in sigmoidal reef deposits. In order to further quantify the process of early dolomitization, mineralogy, isotopes C and O, trace elements, and the Sr-isotopes were examined as well.

Made available in DSpace on 2014-06-11T19:32:20Z (GMT). No. of bitstreams: 0 Previous issue date: 2003-07-31Bitstream added on 2014-06-13T21:03:59Z : No. of bitstreams: 1 fortes_e_dr_rcla.pdf: 3795155 bytes, checksum: 325b5a6aa2479f67ec71e4954cc2fa16 (MD5) / O rio Ivinhema constitui um importante afluente da margem direita do rio Paraná e drena uma série de terraços, superfícies geomorfológicas e feições associadas, a despeito de as baixas declividades sugerirem, numa análise preliminar, um relevo monótono e homogêneo. A presente tese teve como propósito maior o estudo das feições do relevo na área do baixo curso do rio Ivinhema, buscando compreender a sua evolução, no contexto de suas estruturas, de suas morfologias e de seus depósitos sedimentares. Os estudos, realizados na escala 1:60.000, permitiram a identificação de terraços, planícies, leques aluviais e superfícies erosivas. O Terraço Alto (TRA) corresponde à superfície mais elevada e antiga da área de trabalho; o Terraço Médio (TRM), identificado pela grande quantidade de depressões e lagos, que emprestam uma característica peculiar a essa superfície, pois representam um nível rebaixado por processos tectoerosivos do Terraço Alto. O Terraço Baixo (TRB) apresenta uma série de paleocanais posicionados em até 10m de altura em relação ao canal atual do rio Ivinhema, denotando atividade tectônica holocênica. A Planície do Rio Ivinhema divide-se em alta (PRIa) e baixa (PRIb), e corresponde a uma superfície plana, cuja largura aumenta para montante; freqüentemente ela pode ser inundada pelas águas do rio Ivinhema, à exceção do trecho próximo ao Terraço Baixo que se encontra soerguido. A planície do rio Paraná representa igualmente uma área plana, freqüentemente inundada pelas águas do rio homônimo, e apresenta, em seu interior, paleoilhas, cuja coalescência teria sido responsável pela formação da referida planície. Os Leques Aluviais Alto (LEA) e Baixo (LEB) constituem cones de dejeção, cuja diferenciação é de caráter topográfico e temporal...

The Agua Blanca fault is a major transverse structure of northern Baja California, extending more than 120km east from the Punta Banda ridge near the city of Ensenada to the San Matais Pass in central Baja. Through much of its eastern extent slip on this fault appears to be pure strike slip, however, at the Valle de Santo Tomás the fault makes a ~25°; change in orientation, which coincides with the formation of extensional basins on the fault. Recent evidence of the independent movement of the Baja Micro-plate relative to a stable Southern California Black leads to several possible hypotheses to explain this including: 1)That basins are localized structures, the result of a series of right steps or bends along the dextral Agua Blanca fault. 2)Basins are transtensional, possibly as a result of complexities associated with the northern boundary of the Baja Micro-plate . To test between these hypotheses it was necessary to constrain the fault kinematics on both basin bounding and in-basin faults, well as the basin geometry. This was accomplished through combined structural and geophysical surveys. Data collected suggest that the majority of dip-slip is confined to the Santo Tomás fault bounding the basin to the south, while the Agua Blanca fault bounding the basin to the north is primarily strike slip. This orientation typical in transtensional basins, suggesting that although Valle de Santo Tomás formed at a step over it is not a pull apart basin. Possible explanations for transtension in this area come from the orientation of the Agua Blanca fault in relation to the Baja Micro-plate. Where the fault is close to aligned with the relative motion of the plate there is little transtension, such as in Valle de Agua Blanca, however, where the fault makes a 25° change in orientation and becomes more oblique the motion of the Baja Micro-plate transtension is present.

Diploma thesis deals with the proposal of creating a marketing strategy for the newly emerging company. First, the emphasis is on the analysis of the internal and external environment of the emerging company along with the conduct of marketing research. The proposal includes a marketing strategy, determination of the time perspective, identification of possible risks and measures for their reduction and cost calculation.

Human land use legacies have significant and long lasting impacts across landscapes. However, investigating the impacts of ancient land use legacies ( > 400 years) remains problematic due to the difficulty in detecting ancient land uses, especially those beneath dense canopies. The city of Caracol, one of the most important Maya archaeological sites in Belize, was abandoned after the collapse of the Maya civilization (ca. A.D. 900), leaving behind numerous structures, causeways, and agricultural terraces that persist beneath the dense tropical forest of western Belize. LiDAR (Light Detection and Ranging) technology enables detection of below canopy Maya archaeological features, providing an ideal opportunity to study the effects of ancient land use legacies on contemporary tropical forest composition. LiDAR also provided us with a detailed record of the 3-dimensional forest structure over the 200 km2 study area. This allowed the investigation how ancient land uses continue to impact both forest composition, in terms of tree species, and forest structure. I recorded tree species over four land use categories: 1) structures, 2) causeways, 3) terraced, and 4) non-terraced land. Using non-metric multidimensional scaling (NMS) and multiresponse permutation procedures (MRPP) to test for differences between the classes, I found significantly distinct tree communities associated with the presence of terraces and the underlying topography. Terraced slopes appear to function as micro-valleys on the side of a hill, creating an environmental "bridge" between slope and valley tree communities. Tree species composition over causeways and structures was also found to be significantly different from terraced and non-terraced plots. Forest structure was assessed by extracting LiDAR points for terraced (n=150) and nonterraced (n=150) 0.25 ha plots. I calculated average canopy height, canopy closure, and vertical diversity from the height bins of the LiDAR points, using slope, elevation, and aspect as covariates. Using PerMANOVA I determined that forest structure over terraces was significantly different from non-terraced land. Terraces appear to mediate the effect of slope, resulting in less structural variation between slope and non-sloped land. These results led to the conclusion that human land uses abandoned >1000 years ago continue to impact the contemporary forests.

Coastal Louisiana U.S. is facing wetland loss caused mainly by geologic subsidence and sea-level rise. These losses are accelerated by human activities such as the creation of canals and waterways for gas and oil extraction. Wetland loss in coastal Louisiana has encouraged to the implementation of various wetland restoration techniques. Marsh terraces are a one restoration technique consisting of segmented berms of soil that are built in inland coastal ponds. They are designed to increase marsh area, dissipate wind driven waves, encourage marsh expansion, and possibly reduce shoreline erosion. Marsh terraces have been implemented for almost 30 years; however, little research has been conducted to determine their effectiveness at reducing wave energy. Therefore, the overall goal of this research is to find the most optimal terrace design at reducing significant wave height, and therefore wave energy. The specific objectives of this study are to 1) assess terrace performance and longevity over time, 2) simulate wave climates in marsh terrace sites and determine the effectiveness of marsh terraces for the reduction of wave energy, and 3) assess the effectiveness of different terrace designs at reducing significant wave height during low winds and cold front passages in coastal Louisiana. These objectives were accomplished through remote sensing and numerical wave modeling. This study found that there was more predominant deposition than erosion in 20 marsh terrace fields. The study also used a numerical model to simulate small, high frequency waves in two terrace sites, finding an agreement between modeled and observed data. Moreover, wave height was reduced in terrace sites compared to unterraced sites. Finally, it was found that the chevron design is the most optimal terrace design at reducing significant wave height in a variety of wind conditions. This study adds to our knowledge of marsh terrace performance. In this way, marsh terraces may be used as an effective restoration technique at reducing wave energy, not just in Louisiana, but throughout the Gulf Coast, the U.S., and other coasts worldwide that are facing wetland loss.

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