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calcium

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Journal Article
Published: 15 January 2025
Journal of the Geological Society (2025) 182 (2): jgs2024-019.
... ocean circulation and chemical inventories . Earth and Planetary Science Letters , 76 , 135 – 150 , doi: 10.1016/0012-821X(85)90154-2 10.1016/0012-821X(85)90154-2 Bradbury , H.J. and Turchyn , A.V. 2018 . Calcium isotope fractionation in sedimentary pore fluids from ODP Leg 175...
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First thumbnail for: Diagenetic impacts on Ca isotopes and Mg/Ca ratios...
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Journal Article
Published: 22 October 2024
Journal of Foraminiferal Research (2024) 54 (4): 355–374.
...: 10.5194/bg-10-6375-2013 . Zhou, X., Rosenthal, Y., Haynes, L., Si, W., Evans, D., Huang, K.-F., Hönisch, B., and Erez, J. 2021 , Planktic foraminiferal Na/Ca: A potential proxy for seawater calcium concentration : Geochimica et Cosmochimica Acta...
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First thumbnail for: INTRATEST TRACE ELEMENT VARIABILITY IN POLAR AND S...
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Journal Article
Published: 27 September 2024
Quarterly Journal of Engineering Geology and Hydrogeology (2024) 57 (4): qjegh2023-090.
... investigated the effects of adding calcium chloride (CaCl 2 ) and using EKS techniques on the soil shear characteristics (shear strength and its two components: cohesion and internal friction angle) of three different soil layers in collapsing gullies. The results showed that the EKS techniques significantly...
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First thumbnail for: Effects of electrokinetic stabilization combined w...
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Journal Article
Published: 25 September 2024
Quarterly Journal of Engineering Geology and Hydrogeology (2024) 57 (4): qjegh2024-029.
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First thumbnail for: Influence of wet–dry cycles on the disintegration ...
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Journal Article
Published: 01 September 2024
American Mineralogist (2024) 109 (9): 1523–1534.
FIGURES
First thumbnail for: K isotopic fractionation in K-feldspar: Effects of...
Second thumbnail for: K isotopic fractionation in K-feldspar: Effects of...
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Journal Article
Journal: Lithosphere
Publisher: GSW
Published: 10 July 2024
Lithosphere (2024) 2024 (3): lithosphere_2024_154.
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First thumbnail for: Re−Os Isotope and PGE Abundance Systematics of Coa...
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Journal Article
Journal: Geology
Published: 23 May 2024
Geology (2024) 52 (9): 641–645.
... the global carbon cycle. Recent studies of calcium isotopes (δ 44/40 Ca) in shallow-water carbonates indicate that δ 44/40 Ca can be altered during early marine diagenesis, implying that δ 13 C may also potentially be altered. Here, we tested the hypothesis that the platform carbonate δ 13 C record...
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First thumbnail for: Early Mississippian global δ 13 C excursion is not...
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Journal Article
Journal: Economic Geology
Published: 01 May 2024
Economic Geology (2024) 119 (3): 681–712.
... ( Anenburg et al., 2020a , 2022 ; Yuan et al., 2023 ). Some carbonatites, however, exhibit initial magmatic deposition of REE phases ( Wall and Mariano, 1996 ; Zaitsev et al., 2002 ; Weng et al., 2021 ; Zheng et al., 2023 ) or REE sequestration by calcium minerals (e.g., apatite; Bühn, 2001...
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First thumbnail for: The Origin and Evolution of Rare Earth Element Min...
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Third thumbnail for: The Origin and Evolution of Rare Earth Element Min...
Journal Article
Published: 29 April 2024
Journal of the Geological Society (2024) 181 (4): jgs2023-184.
...Alexander J. Krause; Graham A. Shields; Robert J. Newton; Benjamin J. W. Mills Abstract Understanding the long-term variations in seawater sulfate concentrations ([SO 4 2− ] sw ) is crucial to our understanding of the dynamic relationships between the sulfur, carbon, calcium and oxygen cycles...
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First thumbnail for: Modelling sulfate concentrations in the global oce...
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Third thumbnail for: Modelling sulfate concentrations in the global oce...
Journal Article
Published: 15 April 2024
Journal of Foraminiferal Research (2024) 54 (2): 81–94.
... portion of each ablation profile was selected in order to exclude any surface contamination and artifacts of beam penetration (Fig. A1). International reference materials from the USGS (MACS-3 synthetic calcium carbonate) and NIST (SRM 610 and 612 silicate glasses), were used for calibration and quality...
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First thumbnail for: Sightings of the Rare Globorotalia Cavernula in th...
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Journal Article
Journal: Geoenergy
Published: 10 April 2024
Geoenergy (2024) 2 (1): geoenergy2023-053.
..., the resulting high potassium level actively promotes the illitization of feldspars ( Alekseyev et al. 1997 ; Zhu and Lu 2009 ). With the accumulation of calcium (or magnesium or sodium) in the system, swelling clays such as montmorillonite can be formed. In addition to weathering, hydrothermal alteration...
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First thumbnail for: Fracture smectites in bedrock at the Kivetty and R...
Second thumbnail for: Fracture smectites in bedrock at the Kivetty and R...
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Journal Article
Journal: Clay Minerals
Published: 26 February 2024
Clay Minerals (2024) 59 (1): 39–49.
...) are listed in Table 1 . Raw CLN is rich in potassium and calcium and has a SiO 2 /Al 2 O 3 ratio of 5.7. Compared to the raw material, the parent sample prepared using Method 2 showed significant changes in its chemical composition and significant removal of exchangeable cations from the structure without...
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First thumbnail for: Natural and pretreated Gördes clinoptilolites for ...
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Journal Article
Published: 13 February 2024
Journal of Foraminiferal Research (2024) 54 (1): 1–19.
... seawater , and iteratively solves for the latter two variables and their respective uncertainties in a Monte Carlo framework ( Thirumalai et al., 2016 ). We reconstruct seawater temperatures using the following published calibration equations, where Mg/Ca is the magnesium to calcium ratio in measured...
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First thumbnail for: Morphotypical and Geochemical Variations of Plankt...
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Journal Article
Published: 01 December 2023
American Mineralogist (2023) 108 (12): 2331–2337.
...Fei Qin; Ye Wu; Shengchao Xue; Dongzhou Zhang; Xiang Wu; Steven D. Jacobsen Abstract Alkali-rich aluminous high-pressure phases including calcium-ferrite (CF) type NaAlSiO 4 are thought to constitute ~20% by volume of subducted mid-ocean ridge basalt (MORB) under lower mantle conditions...
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Journal Article
Journal: Geology
Published: 07 November 2023
Geology (2024) 52 (1): 51–55.
... to the residence times of boron (~10 m.y.) and calcium (~1 m.y.) within the ocean ( Broecker and Peng, 1982 ; Lemarchand et al., 2000 ), decreases in the [B(OH) 4 – ]/DIC ratio suggest a decrease in seawater borate concentrations due to a decrease in pH (which decreases the abundance of [B(OH) 4 – ] relative...
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First thumbnail for: Warming, acidification, and calcification feedback...
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Journal Article
Journal: Elements
Published: 01 October 2023
Elements (2023) 19 (5): 296–301.
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First thumbnail for: The Franklin Large Igneous Province and Snowball E...
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Journal Article
Published: 01 October 2023
Jour. Geol. Soc. India (2023) 99 (10): 1349–1360.
... during the interglacial stages, Holocene and interstadial events. The increased total carbonate, elemental concentrations (calcium, barium and phosphorous) and decreased magnetic susceptibility values correlate with the enhanced monsoon intensities during the above events. Glacial stages and millennial...
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First thumbnail for: Paleoclimatic Influence on the Evolution of the La...
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Journal Article
Journal: Geology
Published: 12 September 2023
Geology (2023) 51 (12): 1091–1095.
...Selina R. Cole; David F. Wright; Jeffrey R. Thompson Abstract Seawater magnesium (Mg) and calcium (Ca) have undergone secular fluctuations throughout the Phanerozoic, controlling whether the dominant calcium carbonate precipitant is calcite or aragonite + high-Mg calcite. Although...
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First thumbnail for: Calcite-aragonite seas as a driver of echinoderm e...
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Journal Article
Journal: Clay Minerals
Published: 02 August 2023
Clay Minerals (2023) 58 (2): 113–120.
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First thumbnail for: Theoretical analysis of the effect of doping with ...
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Journal Article
Published: 01 August 2023
Russ. Geol. Geophys. (2023) 64 (8): 950–961.
... ). A calcium mineral, danburite, seems to be the most stable among other borosilicates and decomposes only at ~1000 °C with the formation of crystobalite and wollastonite, as well as gaseous B 2 O 3 ( Brun and Ghose, 1964 ). Data on the high-temperature behavior of the strontium analogue of paracelsian, i.e...
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First thumbnail for: Phase Transformations in Feldspar Group Minerals w...
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