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Showing 1 to 20 of 21 for “"Stalagmite"”.
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An examination of trace element concentrations across calcite/aragonite transitions in a Madagascan stalagmite
Calcite and aragonite speleothems have been used for the past few decades to provide paleoclimate information, but in speleothems of mixed mineralogy the signal of mineral changes can complicate understanding of climate signals also present. This mineral signal must therefore be examined and …
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Recent extreme events in a tropical stalagmite: Multi-proxy records and analysis of ecosystem delta carbon-13 value sensitivity to weak climate forcing
… of a rapidly growing, fracture-fed tropical stalagmite. A series of sample screening steps were developed prior to stalagmite collection in the field in order to increase the likelihood of collecting suitable samples sensitive to tropical cyclone precipitation events. Once the correct annual …
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Paleoclimate reconstructions over the last century from a tropical speleothem on Niue Island, South Pacific
… The focus of this study is an actively growing stalagmite sampled from a flank margin cave (Avaiki Cave) that contains about 146 years of deposition (2002-1856 AD). The stalagmite consists of sub-annual couplets alternating between white porous calcite laminae deposited during the austral summer …
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Geochemistry of karst deposits in Borneo detailing hydroclimate variations in the Warm Pool across the late Pleistocene
… of orbital-scale variations. Here we present stalagmite oxygen isotope (δ18O) reconstructions from Gunung Mulu National Park (4oN, 115oE ), in northern Borneo, that provide reproducible centennial-scale records of western Pacific hydrologic variability that are precisely U/Th-dated and …
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Records of Great Basin precipitation during MIS 11 from two Lehman Cave stalagmites
… and [delta]18O) were measured in two coeval stalagmites, LC3 and BT1, from the Lehman Caves, Nevada. BT1 spans 388 to 384 ka. The LC3 record is split into two parts due to a hiatus observed through fluorescent imaging. The section prior to the hiatus spans 411 ka to 402 ka. The post-hiatus …
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Interpretations of Paleoclimate and Speleogenesis from Speleothems in Donnehue's Cave, Indiana
… are cave deposits, especially speleothems (stalagmites and flowstones). A major obstacle in the overall understanding of continental climatic fluctuations in the Midwest is the scarcity of the well-dated paleoclimate records. This investigation provides additional data from the …
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GEOCHEMISTRY AND PETROGRAPHY OF SPELEOTHEMS FROM TURKEY AND IRAN: PALAEOCLIMATE AND DIAGENESIS
… from Torang Cave, Iran. The older Dim Cave stalagmite, which precipitated during MIS 5e, was not identified as a recrystallised stalagmite at first, as the mineralogy of the growth axis appeared to show a change in primary mineral rather than recrystallisation. Despite the fact that …
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CHARACTERIZATION OF THE NORTHERN HEMISPHERE GLACIAL CYCLE-II AND TERMINATION FROM HIGH RESOLUTION SPELEOTHEM ISOTOPE AND TRACE ELEMENTAL TIME-SERIES DATA, SOUTHWEST UNITED STATES
… monsoon event observed in southeast (SE) China stalagmites SB11 (Cheng et al. 2009) and MSX (Cheng et al. 2006) during a NH insolation minimum ~ 135,000 – 130,000 years ago. Close correspondence between the SE China and SW USA speleothem record reveal a three step termination in association with …
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Speleothem Palaeoclimatology in the Maya Lowlands of Northwestern Yucatán, Mexico
… and uranium series disequilibrium dating on the stalagmite Tzab06-1, I reconstruct the precise duration, timing, and relative severity of wet season droughts in the Terminal Classic. This is the first proxy record from the northern Yucatán resolved on seasonal timescales, and can be directly …
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Speleothem-based hydroclimate proxies and Late-Quaternary paleoclimate in the Western Mediterranean
… In the first publication of this thesis, a stalagmite record (OV12-5) from Monaco, with an average temporal resolution of 5 years for δ¹⁸O and δ¹³C, was presented, revealing multi-centennial arid events during MIS 5a. These arid events are interpreted to be associated with a northward …
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Changes in monsoonal precipitation and atmospheric circulation during the Holocene reconstructed from stalagmites from Northeastern India
Recent years witnessed a vast advent of stalagmites as palaeoclimate archives. The multitude of geochemical and physical proxies and a promise of a precise and accurate age model greatly appeal to palaeoclimatologists. Although substantial progress was made in speleothem-based palaeoclimate …
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Organic complexation in karst cave systems: implications for transition metal incorporation into speleothems
… concentrations of first-row transition metals in stalagmites has been proposed to potentially offer a first means to quantitatively reconstruct past cave drip rates, and hydroclimate by extension. The transport from the surface to the site of speleothem formation of transition metals, such as Co, …
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A 20,000 year flowstone record of Gulf of Mexico sourced moisture in Texas
… paleoclimate reconstructions when high-quality stalagmite samples are not available.
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Late Holocene Paleoenvironmental Reconstruction in Barbados
… distinct layers of detritus within the stalagmite sample, facilitating precise sampling for U-series dating while also providing some information on the nature of weathering on the island. Additionally, time series analysis of the isotope record indicates multidecadal and multicentennial …
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Cave air and dripwater variability in Cathedral Caverns, Alabama
… and more potential calcite deposition onto the stalagmite. The [DIC] and δ13CDIC which range from 0.6 to 6.0 mM and -4.7 to -14.7‰, respectively, show that [DIC] is at a maximum and δ13CDIC is 13C-depleted during summer months. These results indicate that the paleoclimate record in Cathedral …
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Investigating Mexican paleoclimate with precisely dated speleothems
… three records from newly-analyzed Mexican stalagmites using stable isotope (oxygen and carbon) and trace element to calcium (Mg/Ca and Sr/Ca) ratios as proxies for changing hydroclimate. Chapter 2 presents a precisely dated, mid-Holocene record of high rainfall and limited precipitation …
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On the external forcing of Indian Ocean climate variability across timescales
… data. Chapter 2 presents a novel geochemical stalagmite record from northern Madagascar which spans the end of the last glacial period. Stable isotope and trace metal proxies indicate drier conditions in response to North Atlantic cooling events, such as Heinrich stadials, and wetter …
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On the external forcing of Indian Ocean climate variability across timescales
… data. Chapter 2 presents a novel geochemical stalagmite record from northern Madagascar which spans the end of the last glacial period. Stable isotope and trace metal proxies indicate drier conditions in response to North Atlantic cooling events, such as Heinrich stadials, and wetter …
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A central Texas drying event identified at the Younger Dryas-early Holocene transition using coupled speleothem 𝛿¹³C-¹⁴C analysis
… We use moisture proxies from a central Texas stalagmite record (McN-1) collected in the Edwards aquifer (an important human and ecological groundwater resource in central Texas) to assess how epikarst moisture conditions varied in the region during the YD-Holocene transition. The relatively …
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Dating and Interpretation of Secondary Carbonate Deposits from the Last Interglacial
… profiles taken along the growth axis of a stalagmite from Spannagel Cave suggest, that the solar activity influenced Eemian climate, as the detected periodicities are similar to some well–known solar cycles. The existence of cycles with a periodicity of ~1470 years …
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