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SummaryThe conductive and capacitive properties of rocks are influenced by the type and concentration of the electrolyte present in the pore water. Sodium (Na⁺) and potassium (K⁺) are common pore water cations in saturated sedimentary rocks. Their distinct physicochemical properties are expected to produce different frequency-dependent electrical dispersion when adsorbed onto mineral surfaces. We tested this expectation by using spectral induced polarization (SIP), a method sensitive to interfacial processes. Complex conductivity spectra (10–2 to 105 Hz) were measured on two clayey, opal-A-rich diatomite samples, saturated with either NaCl or KCl solutions. One sample was tested over a stepwise increase in molar concentration (5.4–53 mM), while the other was tested over a stepwise increase in bulk water conductivity (0.050–0.48 S/m). At equivalent molar concentration, the in-phase conductivity of a sample was ~20 per cent higher when KCl saturated than when NaCl saturated, reflecting the greater molar conductivity of K⁺. At matched bulk water conductivity, which required a ~20 per cent higher NaCl molarity than KCl molarity, in-phase conductivity was ~10 per cent higher when NaCl saturated. In both tests, the quadrature conductivity and normalized chargeability followed a lower trend in the KCl-saturated state than in the NaCl-saturated state. This relatively low polarization for the K+ saturated state can be attributed to a weaker hydration and more compact adsorption of K⁺ within the inner layer of the electrical double layer. Additionally, time-lapse monitoring of complex conductivity spectra indicates that chemical equilibration via diffusion is achieved within 72 hours for both electrolyte types. This relatively rapid ionic diffusion is consistent with estimates based on the intrinsic formation factor and probably reflects the high porosity of the diatomite (~0.7). These findings establish that pore-water cation identity (Na⁺ vs. K⁺) is a primary control on SIP-derived polarization parameters, and cation identity must therefore be incorporated into petrophysical models to avoid biased estimates of surface area, permeability, and hydrogeochemical state.

Publication date: 15 August 2026

Source: Earth and Planetary Science Letters, Volume 688

Author(s): Fabrizio Di Fiore, Alessio Pontesilli, Giacomo Pozzi, Gianmarco Buono, Laura Calabrò, Silvio Mollo, Lucia Pappalardo, Piergiorgio Scarlato, Claudia Romano, Jacopo Taddeucci, Alessandro Vona

Publication date: 15 August 2026

Source: Earth and Planetary Science Letters, Volume 688

Author(s): Pingchuan Tan, Jiabiao Li, Jie Chen, Zhiteng Yu, Chunyang Wang

Publication date: 15 August 2026

Source: Earth and Planetary Science Letters, Volume 688

Author(s): Hongxi Pang, Tao Xu, Wangbin Zhang, Shuangye Wu, Shugui Hou

Publication date: Available online 21 May 2026

Source: Earth and Planetary Science Letters

Author(s): Sher-Rine Kong, Willem G.M. van der Bilt, Pål Tore Mørkved, Lars Wörmer, Katarzyna Hasal, William J. D’Andrea

Publication date: 15 August 2026

Source: Earth and Planetary Science Letters, Volume 688

Author(s): Yuanyuan Hua, Dapeng Zhao, Yang Yu, Yi-Gang Xu, Xiao-Long Huang

Publication date: 15 August 2026

Source: Earth and Planetary Science Letters, Volume 688

Author(s): Xianjun Fang, Sean D. Willett, Rong Yang, Dirk Scherler, Negar Haghipour, Marcus Christl

Publication date: 15 August 2026

Source: Earth and Planetary Science Letters, Volume 688

Author(s): Konrad Greinwald, Aaron Bufe, Theresa Blume, Dominic Demand, Markus Egli, Tobias Gebauer, Anne Hartmann, Fabian Maier, Ilja van Meerveld, Alessandra Musso, Michael Scherer-Lorenzen, Markus Weiler

Publication date: 15 August 2026

Source: Earth and Planetary Science Letters, Volume 688

Author(s): Nico Bigaroni, Fabio Trippetta, Corentin Noël, Carolina Giorgetti, Cristiano Collettini

Publication date: 15 August 2026

Source: Earth and Planetary Science Letters, Volume 688

Author(s): Francis Nimmo, Sujoy Mukhopadhyay

Publication date: Available online 12 May 2026

Source: Earth and Planetary Science Letters

Author(s): Liam Moser, Matěj Peč, Camilla Cattania

Publication date: 15 May 2026

Source: Advances in Space Research, Volume 77, Issue 10

Author(s): Jin-Cherng Hsu, Wei-Yu Chen, Chih-Hsuan Shih, Guo-Yu Yu, Yung-Shin Sun, Hsing-Yu Wu

Publication date: 15 May 2026

Source: Advances in Space Research, Volume 77, Issue 10

Author(s): Tiantian Qing, Hao Zhou, Ming Li, Le Suo, Zhu Zhu, Mingyang Xia, Yaozong Li, Lijun Zheng, Shuyun Zheng, Siyou Xu, Zhicai Luo

Publication date: 15 May 2026

Source: Advances in Space Research, Volume 77, Issue 10

Author(s): Yu Zhao, Xin Ma

Publication date: 15 May 2026

Source: Advances in Space Research, Volume 77, Issue 10

Author(s): Ramin Saadi Esfangareh, Fatemeh Imanpour, Mahdi Hasanlou

Publication date: 15 May 2026

Source: Advances in Space Research, Volume 77, Issue 10

Author(s): Carlo Scotto, Dario Sabbagh, Alessandro Ippolito, Loredana Perrone

Publication date: 15 May 2026

Source: Advances in Space Research, Volume 77, Issue 10

Author(s): Mefe Moses, Trisani Biswas, Haris Haralambous, Krishnendu Sekhar Paul

British demand for everyday global commodities can be linked to more than 29,000 hectares of deforestation worldwide in a single year, with tens of thousands of hectares stripped directly from overseas ecosystems. The stark figure forms the centerpiece of an environmental assessment released by the Stockholm Environment Institute (SEI) at the University of York.

The ocean is an important carbon sink that absorbs 20–30% of the total anthropogenic CO2 emissions in the industrial era (1.0–3.0 Pg annually, 1 Pg = 1015 g). Tropical cyclones are among the most devastating weather systems that profoundly disturb the upper ocean. However, their role in the global carbon cycle has been controversial: do tropical cyclones lead to net carbon absorption or release by the ocean, and does it matter?

Located in the middle of the North Pacific, between Japan and Canada, lies one of the world's largest oceanic plateaus, the so-called Hess Rise. The plateau is roughly T-shaped and extends over a length of about 1,000 kilometers. Due to its distance from the nearest mainland, the research area at Hess Rise is difficult to access and has therefore been the destination of only a few expeditions to date.