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Mineralogical and geochemical data of two weathering profiles in a Mediterranean and a humid climate region of the Chilean Coastal Cordillera

This publication provides mineralogical and geochemical data of two 6-m-deep weathering profiles formed from granitic rock. They are located in different climate zones (Mediterranean and humid) and are close to the national parks of La Campana and Nahuelbuta in the Chilean Coastal Cordillera. Additional rock samples from adjacent boreholes were used to relate the regolith to the bedrock. The profiles were sampled in February and March 2020 as part of the German Science Foundation (DFG) priority research program SPP-1803 “EarthShape: Earth Surface Shaping by Biota”. The goal of this project is to obtain a holistic view on the interplay of the geosphere and the biosphere under different climatic conditions and to investigate weathering mechanisms. The aim of this publication is to provide the data basis for understanding the weathering processes that control the development of the profiles in relation to different climatic conditions. To this end, we measured the geochemistry with X-ray fluorescence, extracted Fe, Al and Si with oxalate/dithionite, determined the grain sizes by wet sieving and pipetting, measured the magnetic susceptibility, and analysed the mineral content of bulk samples and clay fractions with X-ray diffraction. The data are compiled in one Excel file and all results of the X-ray diffraction measurements are available as RAW- and TXT files.

Physical and geochemical data on a drill core from the semi-arid Coastal Cordillera, Chile

This dataset contains petrophysical, geochemical, and mineralogical data from a drilling core from the Coastal Cordillera, Chile. The drilling campaign in the semi-arid field site Reserve Santa Gracia was conducted in the framework of the “EarthShape” project (DFG SPP1803) to study deep weathering along a climate gradient. Previous studies in this area found that the weathering front is located much deeper than expected (Oeser et al., 2018). To explore the weathering profile and the depth of the weathering front, we performed various geochemical, petrophysical, and mineralogical analyses. The drilling campaign was conducted in March and April 2019, using the wireline drilling method with a standard industry truck-mounted PQ3-sized (85 mm core diameter, 123 mm hole diameter) rotary drilling rig (Sondajes Araos E.I.R.L.). A detailed description of the drilling activities is given in Krone et al. (2021). The retrieved core runs with a maximum length of 1.5 m were drilled using potable water, with added contamination control tracer for further microbiological analyses of the rock. As basis for our detailed study of deep weathering we determined the porosity, density, specific surface area, elemental composition, mineralogical composition, Fe oxidation, and the degree of weathering from chemical depletion, volumetric strain, and the weathering rate using the in situ cosmogenic nuclide beryllium-10 (10Be).

Major and trace element concentrations in hydrological Critical Zone compartments in the Conventwald (Black Forest, Germany)

This dataset contains element concentrations of six different hydrological compartments sampled on a daily basis over the course of one year in two neighboured first order headwater catchments located in the Conventwald (Black Forest, Germany). Critical Zone water compartments include above-canopy precipitation (bulk precipitation including rainwater, snow and fog water), below-canopy precipitation (throughfall), subsurface flow from three distinct soil layers (organic layer, upper mineral soil, deep mineral soil), groundwater, creek water and spring water. Element concentrations include major elements (Ca, K, Mg, Na, Si, S), trace elements (Al, Ba, Cr, Cu, Fe, Li, Mn, P, Sr, Zn), anion (Cl), and dissolved organic elements (DOC, DON). The data were used to explore concentration (C) - discharge (Q) relationships and to calculate short-term element-specific chemical weathering fluxes, which were compared with previously published long-term element-specific chemical weathering fluxes. The ratio of both weathering fluxes, described by the so-called “Dissolved Export Efficiency” (DEE) metric revealed deficits in the stream dissolved load. These deficits were attributed to colloid-bound export and either storage in re-growing forest biomass or export in biogenic particulate form. Tables supplementary to the article, including data quality control, are provided in .pdf and .xlsx formats. In addition, data measured in the course of the study are also provided as machine readable ASCII files.

Geophysical Imaging of Deep EarthShape (GIDES): Seismic data of the Private Reserve Santa Gracia, Chile

The dataset contains the seismic weight drop data acquired in Private Reserve Santa Gracia, Chile. The data acquisition was conducted as a part of the EarthShape project in the subproject of Geophysical Imaging of the Deep EarthShape (GIDES). The seismic line was setup to cut across an existing borehole location with core and geophysical logging data available (Krone et al., 2021; Weckmann et al., 2020). The data was acquired to image the deep weathering zone identified by the borehole data across the seismic profile. Included in the datasets are the raw data of the CUBE data logger, SEG-Y data of the recorded shots, and the shot and receiver geometry data. A vital aspect of comprehending the interplay between geological and biological processes lies in the imaging of the critical zone, located deep beneath the surface, where the transition from unaltered bedrock to fragmented regolith occurs. It had been hypothesized that the depth of such weathering zone is dependent on the climate condition of the area. A more humid climate with higher precipitation will result in a deeper weathering front. As a part of the EarthShape project (SPP-1803 ‘EarthShape: Earth Surface Shaping by Biota’), specifically the Geophysical Imaging of the Deep EarthShape (GIDES - Grant No. KR 2073/5-1), we aim to image the weathering zone using the geophysical approach. Using the seismic method, we can differentiate different weathered layers based on the seismic velocity while also providing a 2D subsurface image of the critical zone. We conducted a seismic weight drop experiment in the Private Reserve Santa Gracia, Chile, to observe the depth of the weathering zone in a semi-arid climate and compare the resulting model with existing borehole data (Krone et al., 2021; Weckmann et al., 2020). The acquired data can then be used for multiple seismic imaging techniques, including body wave tomography and multichannel analysis of surface waves.

Geophysical Imaging of Deep EarthShape (GIDES): Controlled source seismic data of Santa Gracia, Chile

The dataset contains the seismic weight drop data acquired in Private Reserve Santa Gracia, Chile. The data acquisition was conducted as a part of the EarthShape project in the subproject of Geophysical Imaging of the Deep EarthShape (GIDES). The seismic line was setup to cut across an existing borehole location with core and geophysical logging data available (Krone et al., 2021; Weckmann et al., 2020). The data was acquired to image the deep weathering zone identified by the borehole data across the seismic profile. Included in the datasets are the raw data of the CUBE data logger, SEG-Y data of the recorded shots, and the shot and receiver geometry data. A vital aspect of comprehending the interplay between geological and biological processes lies in the imaging of the critical zone, located deep beneath the surface, where the transition from unaltered bedrock to fragmented regolith occurs. It had been hypothesized that the depth of such weathering zone is dependent on the climate condition of the area. A more humid climate with higher precipitation will result in a deeper weathering front. As a part of the EarthShape project (SPP-1803 ‘EarthShape: Earth Surface Shaping by Biota’), specifically the Geophysical Imaging of the Deep EarthShape (GIDES - Grant No. KR 2073/5-1), we aim to image the weathering zone using the geophysical approach. Using the seismic method, we can differentiate different weathered layers based on the seismic velocity while also providing a 2D subsurface image of the critical zone. We conducted a seismic weight drop experiment in the Private Reserve Santa Gracia, Chile, to observe the depth of the weathering zone in a semi-arid climate and compare the resulting model with existing borehole data (Krone et al., 2021; Weckmann et al., 2020). The acquired data can then be used for multiple seismic imaging techniques, including body wave tomography and multichannel analysis of surface waves.

Geophysical Imaging of Deep EarthShape (GIDES): 3-components passive seismic data of La Campana, Chile

This data publication provides access to three-component (3C) passive seismic data collected in the National Park La Campana, Chile. The data acquisition was conducted as part of the EarthShape project, specifically the Geophysical Imaging of the Deep Earth (GIDES) initiative. The seismic array was strategically positioned to intersect an existing borehole location. This borehole boasts a wealth of data, including core samples and geophysical logging information. The passive seismic data plays a crucial role in imaging the structure of the deep weathering zone beneath the surface. The dataset includes the raw data captured by the CUBE data logger. This raw data can be converted into the widely used miniSEED format using the freely available GIPP (Geophysical Instruments Pool Potsdam) tools. This conversion facilitates seamless integration with other seismic analysis software, promoting broader utilization of the data by the scientific community.

Mineralogical, geochemical, microbiological and thermodynamic data from a deep hydrothermally altered profile of a semi-arid environment (Chilean Coastal Cordillera)

This data publication is supplementary to a study on microbial weathering of Fe-bearing minerals in the deep biosphere of a semi-arid environment (Chile). The dataset contains mineralogical, geochemical, microbiological and thermodynamic data of an 87 m deep drill core profile located in the Chilean Coastal Cordillera (Santa Gracia (SG)). The drilling campaign was conducted in March-April 2019 as part of the German Science Foundation (DFG) priority research program SPP 1803 “EarthShape: Earth Surface Shaping by Biota”. The project focused on how microorganisms contribute to mineral weathering and thus shape Earth´s surface. Aim of the drilling campaign was to recover the continuous weathering profile from surface to weathering front and to pinpoint as well as disentangle weathering processes at depth. For this purpose, extractable Fe pools, water-extractable organic carbon and nitrate, energy yields of Fe redox reactions, in situ microbial Fe(III) reduction, microbial Fe(III) reduction extent in microcosms, as well as community compositions of in situ and microcosms derived 16S rRNA gene amplicon sequence variants (ASVs) were determined.

Mineralogical, geochemical and magnetic susceptibility data from a deep hydrothermally altered profile in a semi-arid region (Chilean Coastal Cordillera)

This data publication contains mineralogical, geochemical and magnetic susceptibility data of an 87.2 m deep profile of hydrothermally altered plutonic rock in a semi-arid region of the Chilean Coastal Cordillera (Santa Gracia). The profile was recovered during a drilling campaign (March and April 2019) as part of the German Science Foundation (DFG) priority research program SPP-1803 “EarthShape: Earth Surface Shaping by Biota” which aims at understanding weathering of plutonic rock in dependency on different climatic conditions. The goal of the drilling campaign was to recover the entire weathering profile spanning from the surface to the weathering front and to investigate the weathering processes at depth. To this end, we used rock samples obtained by drilling and soil/saprolite samples from a manually dug 2 m deep soil pit next to the borehole. To elucidate the role of iron-bearing minerals for the weathering, we measured the magnetic susceptibility, determined the mineral content and analysed the geochemistry as well as the composition of Fe-bearing minerals (Mössbauer spectroscopy) in selected samples.

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