Surface deformation in the continental interior, away from active tectonic margins, is enigmatic, with the underlying mechanisms responsible not fully understood. Therefore, it is considered an open and important question in continental dynamics. The Hangai Dome, central Mongolia, is a natural laboratory to explore this question. It is a high-elevation, low-relief, intra-continental region within the Mongolian plateau. It is located between the Siberian and North China cratons and lies within the Central Asian Orogenic Belt.
Central Mongolia has a complex tectonic history that is not well understood. It consists of several lithotectonic units that have influenced the formation and development of the region. The Hangai region has a long history of volcanic activity, including Cenozoic episodes of intraplate volcanism, which occurred as recently as the Holocene. It is characterized by dispersed, low-volume, alkali basaltic volcanism. Furthermore, major fault systems bound the Hangai region and large parts of central Mongolia.
The processes and driving mechanisms responsible for creating the Hangai region remain largely unexplained. Therefore, we aim to collect high-resolution magnetotelluric data to image the electrical conductivity structure of the crust and upper mantle beneath the Hangai Dome in order to better understand the mechanisms responsible for intracontinental uplift and intraplate volcanism in this unique region.
To achieve this objective a project was created, titled “Crust-mantle interactions beneath the Hangai Mountains in western Mongolia - Insights from 3-D magnetotelluric studies and 4-D thermo-mechanical modelling”. The first phase of the project was completed in 2016. Magnetotelluric data were recorded across the Hangai Dome in a grid (~400 by ~200 km), with a nominal site spacing of 50 km. Broadband measurements were acquired at each grid node and, additionally, long period measurements were acquired along two profiles. This data report provides details on the data collection, the measurement site locations, the instrumentation, and the data format.
This data publication (https://doi.org/10.5880/GIPP-MT.201613.1) encompasses a detailed report in pdf format with a description of the project, information on the experimental setup, data collection, instrumentation used, recording configuration and data quality. The folder structure and content of the data repository are described in detail in Ritter et al. (2019). Time-series data are provided in EMERALD format (Ritter et al., 2015).
The DFG funded DeepEarthshape project within the SPP1803 EarthShape (second phase) combines several geoscientific methods and approaches to study the weathering zone in detail in dependence of climate conditions. Projects of the first phase have shown that the weathering zone is much deeper than expected, so that the weathering front was never encountered in the excavated soil pits. At depth of 1 – 2 m appreciable amounts of microbial biomass and DNA counts were encountered. It was further found that bacteria and archaea colonizing rock surfaces are close relatives to those from deeper soil zones. Because we do not know a) the depth of weathering; b) the process advancing it; c) whether this advance is driven by water, gases, and/or biological activity and concentrated along faults; d) whether this zone presents a habitat and interacts with the surface biosphere, we have designed a drilling campaign at all four study sites for joint geochemical, biogeochemical and microbiological exploration and a geophysical campaign for imaging the depth and physical properties of the critical zone. The principle hypotheses of the DeepEarthshape projects are: 1) The advance of the weathering front at depth is a recent process that is linked to climate and coupled with erosion at the surface through a biogeochemical feedback 2) Microbial activity in the deep regolith that advances weathering is fuelled by young organic matter. The four study sites are distributed along the coast of Chile to have a similar geological setting at one hand but different climatic conditions.
Here we present the logging data of the first geophysical borehole survey which took place at Santa Gracia, 40 km NE of La Serena (Coquimbo Region, Chile). The data were acquired on the 2nd of April 2019 between . The borehole logging was conducted by COMPROBE. The vertical borehole reached down to 87.2 m depth and had a diameter (PQ) of 83.5 mm.
Surface deformation in the continental interior, away from active tectonic margins, is enigmatic, with the underlying mechanisms responsible not fully understood. Therefore, it is considered an open and important question in continental dynamics. The Hangai Dome, central Mongolia, is an ideal location to explore this because it is a high-elevation, low-relief, intra-continental region within the Mongolian plateau, between the Siberian and North China cratons, and within the Central Asian Orogenic Belt.
The tectonic history of Central Mongolia is not well understood. It consists of several lithotectonic units that have influenced the formation and development of the region. The Hangai region has had intraplate volcanism throughout the Cenozoic, including as recently as the Holocene, in addition to older Mesozoic volcanic activity. It is characterized by dispersed, low-volume, alkali basaltic volcanism. Furthermore, major shear fault systems bound the Hangai region and central Mongolia.
Our objective is to collect high-resolution magnetotelluric data to image the electrical resistivity structure of the crust and upper mantle beneath the Hangai Dome in order to better understand the processes and mechanisms responsible for intracontinental uplift and intraplate volcanism in this unique region, helping shed light on the Hangai region.
Building on the successful first phase of the project (2016), a second phase was completed in 2017. We expanded our magnetotelluric measurement array: to the west along four new profiles; to the south, across the Gobi-Altai mountains; to the north, across the Bulnay fault segments; filling in the previous profiles for denser site spacing. This new grid of data is ~650 km long and ~400 km wide, with a nominal site spacing of 50 km for broadband measurements. In addition, we completed a small profile across the Tariat/Khorgo region and a reconnaissance profile in Zavkhan. This data report provides details on the data collection, the measurement site locations, the instrumentation, and the data format.
This data publication (10.5880/GIPP-MT.201706.1) encompasses a detailed report in pdf format with a description of the project, information on the experimental setup, data collection, instrumentation used, recording configuration and data quality. The folder structure and content of the data repository are described in detail in Ritter et al. (2019). Time-series data are provided in EMERALD format (Ritter et al., 2015).