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M. Teresa Ramírez-Herrera Vladimir Kostoglodov Jaime Urrutia-Fucugauchi 《Geomorphology》2004,58(1-4):291-304
This paper presents the preliminary results from a study of Holocene-emerged shorelines, marine notches, and their tectonic implications along the Jalisco coast. The Pacific coast of Jalisco, SW Mexico, is an active tectonic margin. This coast has been the site of two of the largest earthquakes to occur in Mexico this century: the 1932 (Mw 8.2) Jalisco earthquake and the 1995 (Mw 8.0) Colima earthquake. Measurement and preliminary radiocarbon dating of emergent paleoshorelines along the Jalisco coast provide the first constraints upon the timing for tectonic uplift. Along this coastline, uplifted Holocene marine notches and wave-cut platforms occur at elevations ranging from ca. 1 to 4.5 m amsl. In situ intertidal organisms dated with radiocarbon, the first ever reported for the Jalisco area, provide preliminary results that record tectonic uplift during at least the past 1300 years BP at an average rate of about 3 mm/year. We propose a model in which coseismic subsidence produced by offshore earthquakes is rapidly recovered during the postseismic and interseismic periods. The long-term period is characterized by slow tectonic uplift of the Jalisco coast. We found no evidence of coastal interseismic and long-term subsidence along the Jalisco coast. 相似文献
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Understory and small trees contribute importantly to stemflow of a lower montane cloud forest 下载免费PDF全文
Teresa Margarita González‐Martínez Guadalupe Williams‐Linera Friso Holwerda 《水文研究》2017,31(5):1174-1183
Stemflow (Sf) measurements in tropical rain and montane forests dominated by large trees rarely include the understory and small trees. In this study, contributions of lower (1‐ to 2‐m height) and upper (>2‐m height and <5‐cm diameter at breast height [DBH]) woody understory, small trees (5 < DBH < 10 cm), and canopy trees (>10‐cm DBH) to Sf per unit ground area (Sfa) of a Mexican lower montane cloud forest were quantified for 32 days with rainfall (P) during the 2014 wet season. Rainfall, stemflow yield (Sfy), vegetation height, density, and basal area were measured. Subsequently, stemflow funneling ratios (SFRs) were calculated, and three common methods to scale up Sfy from individual trees to the stand level (tree‐Sfy correlation, P‐Sfy correlation, and mean‐Sfy extrapolation) were used to calculate Sfa. Understory woody plants, small trees, and upper canopy trees represented 96%, 2%, and 2%, respectively, of the total density. Upper canopy trees had the lowest SFRs (1.6 ± 0.5 Standard Error (SE) on average), although the lower understory had the highest (36.1 ± 6.4). Small trees and upper understory presented similar SFRs (22.9 ± 5.4 and 20.2 ± 3.9, respectively). Different Sf scaling methods generally yielded similar results. Overall Sfa during the study period was 22.7 mm (4.5% of rainfall), to which the understory contributed 70.1% (15.9 mm), small trees 10.6% (2.4 mm), and upper canopy trees 19.3% (4.4 mm). Our results strongly suggest that for humid tropical forests with dense understory of woody plants and small trees, Sf of these groups should be measured to avoid an underestimation of overall Sf at the stand level. 相似文献
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Annalisa Cappello Vittorio Zanon Ciro Del Negro Teresa J. L. Ferreira Maria G. P. S. Queiroz 《地学学报》2015,27(2):156-161
Pico, the youngest island of the Azores Archipelago (Portugal), is characterized by a central volcano and a 30‐km‐long fissure zone. Its eruption rate is the highest of the Azores islands, with more than 35 eruptions in the last 2000 years. Here, we estimate the lava‐flow hazard for Pico Island by combining the vent opening probability derived from the spatial distribution of eruptive fissures, the classes of expected eruptions inferred from the physical and chemical characteristics of historical eruptions, and the lava‐flow paths simulated by the MAGFLOW model. The most likely area to host new eruptions is along a WNW–ESE trend centred on the central volcano, with the highest hazard affecting the two main residential zones of Lajes do Pico and Madalena. Our analysis is the first attempt to assess the lava‐flow hazard for Pico Island, and may have important implications for decision‐making in territorial management and future land‐use planning. 相似文献
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Blen Taye Gemeda Ruth Lahoz Ana Teresa Caldeira Nick Schiavon 《Environmental Earth Sciences》2018,77(2):36
The Lalibela rock-hewn churches are one of the most important religious pilgrimage sites in Ethiopia. These churches are carved from the scoriaceous basalt rock substrate, which has been exposed to attack by biological agents with significant loss of surface material. Particularly, the widespread growth of lichens and other microorganisms on the carved surfaces of the churches has proven to represent a substantial threat for the preservation of the site. In this study, laboratory tests have been conducted to assess the feasibility of using laser technology as an efficient cleaning method of biological patina from polymineralic stone substrates. Multi-analytical techniques were applied for the characterization of the stone samples collected from two of the Lalibela churches: Bete Giyorgis and Bete Amanuel. Stone samples artificially inoculated with bacteria, yeast, fungi isolates, and lichen-encrusted samples were laser cleaned using UV and IR laser wavelengths. The high content of Fe and Ti oxides and the high porosity have made the stone surfaces easily susceptible to low-energy laser treatment. Results indicate that laser cleaning can be applied to polymineralic lithotypes and UV irradiation can successfully remove lichen colonies. Further studies need to be conducted to optimize the laser procedure in polymineralic, high porosity stones. 相似文献
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Brian N. Tissot Barbara A. Best Eric H. Borneman Andrew W. Bruckner Cara H. Cooper Heather D’Agnes Timothy P. Fitzgerald Amanda Leland Susan Lieberman Amy Mathews Amos Rashid Sumaila Teresa M. Telecky Frazer McGilvray Brian J. Plankis Andrew L. Rhyne Glynnis G. Roberts Benjamin Starkhouse Todd C. Stevenson 《Marine Policy》2010
As the world’s largest importer of marine ornamental species for the aquaria, curio, home décor, and jewelry industries, the United States has an opportunity to leverage its considerable market power to promote more sustainable trade and reduce the effects of ornamental trade stress on coral reefs worldwide. Evidence indicates that collection of some coral reef animals for these trades has caused virtual elimination of local populations, major changes in age structure, and promotion of collection practices that destroy reef habitats. Management and enforcement of collection activities in major source countries such as Indonesia and the Philippines remain weak. Strengthening US trade laws and enforcement capabilities combined with increasing consumer and industry demand for responsible conservation can create strong incentives for improving management in source countries. This is particularly important in light of the March 2010 failure of the parties to the Convention on International Trade in Endangered Species (CITES) to take action on key groups of corals. 相似文献
19.
Fourteen core samples of Precambrian granitic gneisses from a well drilled in the Green Township, Scioto County, Ohio were studied to determine the origin of alkali feldspar in these rocks. The well intersected the basement at a depth of 1,700 m and penetrated 11.3m of Precambrian crystalline rocks. Petrographically the samples in the upper 6.4 m of the basement core show evidence of severe alteration by the presence of hematite, limonite and chlorite and by the absence of plagioclase. Alkali feldspars from this part of the core are turbid, have a low 2 V of about 10°, are highly enriched in K, have low Na and Rb concentrations, lack cathode luminescence, and form a straight line on a Rb-Sr isochron diagram yielding a date of 599±69 Ma. Core samples from below 6.4 m appear relatively fresh and unaltered. Alkali feldspar from this portion of the core is orthoclase, shows uniform blue luminescence and gives a Rb-Sr date of 1,162±11 Ma. These results indicate that feldspars in the lowest part of the core are primary minerals that crystallized during the Grenville Orogeny, whereas the K-feldspar in the top of the core is of low-temperature secondary origin. The formation of this feldspar is explained as a consequence of chemical weathering of primary feldspar during late Precambrian time to clay minerals that were later reconstituted under low-temperature hydrothermal conditions as K-feldspar (adularia) by reactions with brines derived from the overlying Mt. Simon Formation of Cambrian age.Laboratory for Isotope Geology and Geochemistry (Isotopia), Contribution No. 68 相似文献
20.
Mario Boccaletti Roberto Mazzuoli Marco Bonini Teresa Trua Bekele Abebe 《Journal of African Earth Sciences》1999,29(4):315
Deformation and magmatism within the 90 km wide northern Ethiopian Rift system is concentrated along a narrow zone - the Wonji Fault Belt. Two key areas (the Nazret-Dera and Asela-Ziway areas), located along the eastern margin of the north-northeast to northeast trending Main Ethiopian Rift, have been investigated in order to reconstruct the recent tectonomagmatic evolution of the northern branch of the Main Ethiopian Rift. In these areas, Early Pleistocene volcanic products (Wonji Group) overlie Pliocene volcanic rocks (Eastern Margin Unit). Detailed stratigraphical reconstructions have revealed the presence of several tectonomagmatic units which can be correlated between the two study areas. The stratigraphical and petrological study of these units outlined (1) the bimodal composition (basalts-pantellerites) of the oldest and youngest units and the unimodal character (pantellerites) of the products erupted during the intervening period; (2) the mainly fissural origin of the ignimbrites and oldest basalts; and (3) a mafic/felsic volumetric ratio of 1:5.The geological data suggest that, around the Pliocene-Quaternary boundary, a change in the stress field occurred in this Main Ethiopian Rift sector, passing from a direction of extension roughly orthogonal to the rift shoulders, to oblique rifting related to an east-west trending extension. In this framework the change in the style of volcanism observed in the Nazret-Dera and Asela-Ziway areas can be related to the change of the stress field. A new geodynamic model is presented for the Late Pliocene to Recent evolution of this sector of the Main Ethiopian Rift. According to this model, a large volume of rhyolitic products was erupted during an oblique rifting phase, following a previous period of pure extension. The change in the tectonic regime favoured partial melting of the underplated basalts as a decrease in the pressure and an elevation of isotherms occurred. 相似文献