Reconstructing high-resolution climate using CT scanning of unsectioned stalagmites: A case study identifying the mid-Holocene onset of the Mediterranean climate in southern Iberia

Walczak, Izabela; Baldini, James U.L.; Baldini, Lisa M.; McDermott, Frank; Marsden, Stuart; Standish, Christopher D.; Richards, David A.; Andreo, Bartolomé; Slater, Jonathan

doi:10.1016/j.quascirev.2015.06.013

Cited by 50 publications

(83 citation statements)

References 74 publications

(149 reference statements)

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“…Temporal variability in calcite density of stalagmites (Walczak et al, 2015;Zhang et al, 2010) has been interpreted as a proxy of change in cave system environmental conditions (water flow dynamics, drip water saturation state, cave pCO 2 ), which in turn have been shown by cave monitoring studies to be controlled by above-cave climate (precipitation and temperature), soil conditions, and vegetation density and type. The mechanistic linkage of variability in calcite density to environmental change has been further related to calcite fabrics in stalagmites (Chiarini et al, 2017;Frisia, 2015;Frisia et al, 2000).…”

Section: Potential Of Lid As An Environmental Proxymentioning

confidence: 99%

“…The mechanistic linkage of variability in calcite density to environmental change has been further related to calcite fabrics in stalagmites (Chiarini et al, 2017;Frisia, 2015;Frisia et al, 2000). For cave systems characterized by limited seasonal variability in pCO 2 , calcite density has been proposed as a proxy of water excess (i.e., drip rate) and precipitation amount above the cave (Walczak et al, 2015;Zhang et al, 2010). Denser calcite is interpreted to record higher and less seasonally distributed precipitation and vice versa.…”

Section: Potential Of Lid As An Environmental Proxymentioning

confidence: 99%

“…Thus, XCT scanning can delineate inclusion void spaces, but it cannot delineate whether an inclusion is dominantly liquid-or airfilled in speleothems. Coupled XCT-NCT scanning has application to the interpretation of mineral or inclusion proxy records of speleothems as well as for further development of potential calcite density and fabric proxies of climate (e.g., Shtober-Zisu et al, 2012;Walczak et al, 2015;Zhang et al, 2010). The high-resolution scale of NCT scanning can also distinguish between inclusions that are confined to stalagmite lamina (herein referred to as microinclusions; 10 to~100 μm) and those inclusions that are considered macropores (>100 μm).…”

Section: Introductionmentioning

confidence: 99%

“…Stalagmite records of δ 13 C and trace elements have been used to further constrain climate interpretations as these proxies are sensitive to precipitation amount and cave ventilation, which in turn are typically climate driven (Mickler et al, 2004;Oster et al, 2015). Calcite density has been proposed as a proxy for water excess driven by precipitation differences during stalagmite growth (Walczak et al, 2015;Zhang et al, 2010). Greater understanding of effective moisture, through the development of additional hydroclimate sensitive proxies, is essential to fully understand regional climate history.…”

Section: Introductionmentioning

confidence: 99%

“…Stalagmite δ 13 C, however, is confounded by the presence of old sources of carbon (Noronha et al, 2015;Oster et al, 2010), variability in surface vegetation (Dorale et al, 1998;Frumkin et al, 2000), and soil respiration (Cruz et al, 2006;Denniston et al, 2013). The applicability of the water excess proxy to other stalagmites (Walczak et al, 2015), however, has not yet been tested to the best of our knowledge. Calcite density has been proposed as a proxy for water excess driven by precipitation differences during stalagmite growth (Walczak et al, 2015;Zhang et al, 2010).…”

Section: Introductionmentioning

confidence: 99%

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Mapping Fluid‐Filled Inclusions in Stalagmites Using Coupled X‐Ray and Neutron Computed Tomography: Potential as a Water Excess Proxy

Wortham

Montañez

Rowland

et al. 2019

Geochem Geophys Geosyst

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Application of novel proxies, such as the stable isotope compositions and noble gas concentrations of fossil drip water trapped as inclusions in stalagmites, have the potential to provide unique constraints on past hydroclimate states and surface temperatures. Geochemical analysis of inclusion waters, however, requires an understanding of the three‐dimensional spatial distribution of dominantly liquid‐ versus air‐filled inclusions in a given stalagmite. Here we couple neutron computed tomography and medium‐ to high‐resolution X‐ray computed tomography to map out the three‐dimensional calcite density and distribution of liquid‐ versus air‐filled inclusions within a Sierra Nevada stalagmite (ML‐1), which formed during the last deglaciation (18.5 to 11.7 ka). Comparison of coupled neutron computed tomography‐X‐ray computed tomography results with a time series of stalagmite calcite fabrics indicates that although highest density calcite contains abundant liquid (fluid)‐filled inclusions, calcite density and fabric overall were secondary controls on the liquid inclusion distribution (LID). Furthermore, a multistatistical evaluation of the stalagmite time series indicates a significant relationship at the multicentury‐ to millennial‐scale between LID and calcite δ18O and δ13C that suggests a potential link between LID and water availability to the cave.

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Section: Potential Of Lid As An Environmental Proxymentioning

confidence: 99%

Section: Potential Of Lid As An Environmental Proxymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Mapping Fluid‐Filled Inclusions in Stalagmites Using Coupled X‐Ray and Neutron Computed Tomography: Potential as a Water Excess Proxy

Wortham

Montañez

Rowland

et al. 2019

Geochem Geophys Geosyst

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Changes in biological productivity along the northwest African margin over the past 20,000 years

et al. 2016

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The intertropical convergence zone and the African monsoon system are highly sensitive to climate forcing at orbital and millennial timescales. Both systems influence the strength and direction of the trade winds along northwest Africa and thus directly impact coastal upwelling. Sediment cores from the northwest African margin record upwelling-related changes in biological productivity connected to changes in regional and hemispheric climate. We present records of 230 Th-normalized biogenic opal and C org fluxes using a meridional transect of four cores from 19°N-31°N along the northwest African margin to examine changes in paleoproductivity since the last glacial maximum. We find large changes in biogenic fluxes synchronous with changes in eolian fluxes calculated using end-member modeling, suggesting that paleoproductivity and dust fluxes were strongly coupled, likely linked by changes in wind strength. Opal and C org fluxes increase at all sites during Heinrich Stadial 1 and the Younger Dryas, consistent with an overall intensification of the trade winds, and changes in the meridional flux gradient indicate a southward wind shift at these times. Biogenic fluxes were lowest, and the meridional flux gradients were weakest during the African Humid Period when the monsoon was invigorated due to precessional changes, with greater rainfall and weaker trade winds over northwest Africa. These results expand the spatial coverage of previous paleoproxy studies showing similar changes, and they provide support for modeling studies showing changes in wind strength and direction consistent with increased upwelling during abrupt coolings and decreased upwelling during the African Humid Period.

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Mid‐Holocene rainfall seasonality and ENSO dynamics over the south‐western Pacific

Nava‐Fernandez,

Braun,

Pederson

et al. 2024

The Depositional Record

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El Niño–Southern Oscillation dynamics affect global weather patterns, with regionally diverse hydrological responses posing critical societal challenges. The lack of seasonally resolved hydrological proxy reconstructions beyond the observational era limits our understanding of boundary conditions that drive and/or adjust El Niño–Southern Oscillation variability. Detailed reconstructions of past El Niño–Southern Oscillation dynamics can help modelling efforts, highlight impacts on disparate ecosystems and link to extreme events that affect populations from the tropics to high latitudes. Here, mid‐Holocene El Niño–Southern Oscillation and hydrological changes are reconstructed in the south‐west Pacific using a stalagmite from Niue Island, which represents the period 6.4–5.4 ka BP. Stable oxygen and carbon isotope ratios, trace elements and greyscale data from a U/Th‐dated and layer counted stalagmite profile are combined to infer changes in local hydrology at sub‐annual to multi‐decadal timescales. Principal component analysis reveals seasonal‐scale hydrological changes expressed as variations in stalagmite growth patterns and geochemical characteristics. Higher levels of host rock‐derived elements (Sr/Ca and U/Ca) and higher δ18O and δ13C values are observed in dark, dense calcite laminae deposited during the dry season, whereas during the wet season, higher concentrations of soil‐derived elements (Zn/Ca and Mn/Ca) and lower δ18O and δ13C values are recorded in pale, porous calcite laminae. The multi‐proxy record from Niue shows seasonal cycles associated with hydrological changes controlled by the positioning and strength of the South Pacific Convergence Zone. Wavelet analysis of the greyscale record reveals that El Niño–Southern Oscillation was continuously active during the mid‐Holocene, with two weaker intervals at 6–5.9 and 5.6–5.5 ka BP. El Niño–Southern Oscillation especially affects dry season rainfall dynamics, with increased cyclone activity that reduces hydrological seasonality during El Niño years.

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Reconstructing high-resolution climate using CT scanning of unsectioned stalagmites: A case study identifying the mid-Holocene onset of the Mediterranean climate in southern Iberia

Cited by 50 publications

References 74 publications

Mapping Fluid‐Filled Inclusions in Stalagmites Using Coupled X‐Ray and Neutron Computed Tomography: Potential as a Water Excess Proxy

Mapping Fluid‐Filled Inclusions in Stalagmites Using Coupled X‐Ray and Neutron Computed Tomography: Potential as a Water Excess Proxy

Changes in biological productivity along the northwest African margin over the past 20,000 years

Mid‐Holocene rainfall seasonality and ENSO dynamics over the south‐western Pacific

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