Three-dimensional magnetotelluric imaging of the geothermal system beneath the Gonghe Basin, Northeast Tibetan Plateau

Gao, Jingxiang; Zhang, Haijiang; Zhang, Senqi; Chen, Xiaobin; Cheng, Zhengpu; Jia, Xiaofeng; Li, Shengtao; Fu, Lei; Gao, Lei; Xin, Hailiang

doi:10.1016/j.geothermics.2018.06.009

Cited by 72 publications

(35 citation statements)

References 27 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In the inversion process, we look for a minimum value of the objective function and stop the inversion when this minimum does not change anymore. This is in contrast with other techniques such as in Patro et al [47] or Gao et al [48]. With our approach, we are not compelled to adjust the error floor to reach some preassigned RMS values.…”

Section: Three-dimensional Inversionmentioning

confidence: 89%

Lithospheric Structure of a Transitional Magmatic to Amagmatic Continental Rift System—Insights from Magnetotelluric and Local Tomography Studies in the North Tanzanian Divergence, East African Rift

Plasman

Hautot²,

Tarits

et al. 2019

Geosciences

View full text Add to dashboard Cite

Continental break-up is controlled by several parameters and processes (rheology, inherited structures, magmatism, etc). Their impact, chronology and interactions are still poorly known and debated, particularly when rifting interacts with cratons. In order to better understand the rifting initiation in a cratonic lithosphere, we analysed 22 magnetotelluric (MT) soundings collected along two East-West profiles in two different rift segments of the North Tanzanian Divergence. The North Tanzanian Divergence, where the East African Rift is at its earliest stage, is a remarkable example of the transition between magmatic to amagmatic rifting with two clearly identified segments. Only separated by a hundred kilometers, these segments, Natron (North) and Manyara (South), display contrasted morphological (wide versus narrow), volcanic (many versus a few edifices) and seismic (shallow versus deep activity) signatures. Magnetotelluric profiles across the two segments were inverted with a three-dimensional approach and supplied the resistive structure of the upper lithosphere (down to about 70 km). The Natron segment has a rather conductive lithosphere containing several resistive features (Proterozoic Belt), whereas the Manyara segment displays highly resistive blocks probably of cratonic nature encompassing a conductive structure under the axial valley. The joint interpretation of these models with recent local and regional seismological studies highlights totally different structures and processes involved in the two segments of the North Tanzanian Divergence. We identified contrasted CO2 content, magma upwelling or trapping, in depth regarding the Manyara or the Natron branch and the influence of inherited cratonic structures in the rifting dynamics.

show abstract

Section: Three-dimensional Inversionmentioning

confidence: 89%

Lithospheric Structure of a Transitional Magmatic to Amagmatic Continental Rift System—Insights from Magnetotelluric and Local Tomography Studies in the North Tanzanian Divergence, East African Rift

Plasman

Hautot²,

Tarits

et al. 2019

Geosciences

View full text Add to dashboard Cite

show abstract

“…The MT data shows that there was a partial melting body at depths of 15-35 km in the western Gonghe Basin, with a length of ~41 km and a width of ~34 km (Zhang et al, 2020b). A three-dimensional MT imaging indicated a conductive layer in the middle-upper crust in southeastern Gonghe Basin and a possible magma chamber near Gonghe town (Gao et al, 2018). The seismic results also show partial melting with low-velocity at depths of 1-10 km, 25-40 km and about 60 km in the basin .…”

Section: Introductionmentioning

confidence: 79%

Heat Flow Distribution and Thermal Mechanism Analysis of the Gonghe Basin based on Gravity and Magnetic Methods

Wang

Zeng

Liu

et al. 2021

Acta Geologica Sinica (Eng)

View full text Add to dashboard Cite

Geothermal resource is indispensable as a clean, renewable, stable and cheap resource. Nowadays in China, the Gonghe Basin, located in northeastern Qinghai Province, has been thought to be a promising geothermal area. To explore geothermal energy potential in and around the Gonghe Basin, geophysical means including magnetic and gravity methods were used to plot distribution. Firstly, we inversed Moho depth and Curie point depth in and around the basin using gravity and magnetic data, respectively, through an improved Parker-Oldenburg algorithm. Secondly, seven different thermal models were established, considering radiogenic heat, basement depth, anomalous heat source and simulated corresponding temperature field and heat flow. These were analyzed numerically and we found the high heat flow in the Gonghe Basin coacted with radiogenic heat, an anomalous heat source and conductive heat. The distribution of seismic activities indicates that the Langshan-Wuwei-Gonghe Fault might have provided channels for transporting heat effectively.

show abstract

“…Conductor anomaly C1 was connected to C2-C4, which is located at 0-3 km below the surface. This conductive area with a resistivity of <10 ohm•m is thought to be a clay cap layer with highly conductive characteristics that acts as a cover layer that stores heat and hot liquid in the volcanic system [69,70]. The formation process of clay cap layers in geothermal systems relates to liquids at lower temperatures or to steam condensing at shallow levels to create a highly conductive condensate layer [2].…”

Section: Two-dimensional Occam Inversionmentioning

confidence: 99%

Mapping of Fault and Hydrothermal System beneath the Seulawah Volcano Inferred from a Magnetotellurics Structure

et al. 2021

View full text Add to dashboard Cite

Magnetotellurics (MT) is an important geophysical method for exploring geothermal systems, with the Earth resistivity obtained from the MT method proving to be useful for the hydrothermal imaging changes of the system. In this research, we applied the MT method to map the geothermal system of the Seulawah Agam volcano in northern Sumatra, a site intended for the construction of a geothermal power plant with an estimated energy of 230 Mwe. Herein, 3D MT measurements were carried out, covering the entire area of the volcano and the various intersecting local faults from the Seulimeum segment in the NW–SE direction. Based on Occam 2D inversion, a conductive anomaly (<10 ohm·m) near the surface was identified in response to specific manifestation areas, including the Heutsz crater on the northern side and the Cempaga crater on the southern side. A further conductive anomaly was also found at a depth of 1 km, which was presumably due to a clay cap layer covering the fluid in the reservoir layer below the surface, where the manifestation areas are formed at various locations (where faults and fractures are found) owing to the fluid in the reservoir rising to the surface. The MT modeling also revealed that the reservoir layer in Seulawah Agam lies at a depth of 2 km with a higher resistivity of 40–150 ohm·m, which is the main target of geothermal energy exploration. At the same time, the heat source zone where magma is located was estimated to lie in two locations, namely, on the northern side centering on the Heutsz crater area and the southern side in the Cempaga crater area. A clear 3D structure obtained via Occam inversion was also used to visualize the hydrothermal flow in the Seulawah Agam volcano that originates from two heat source zones, where one structure that was consistent across all models is the conductive zone that reaches a depth of 5 km in the south in response to the regional faulting of the Seulimeum segment. Based on the MT research, we concluded that the volcano has the geothermal potential to be tapped into power plant energy in the future.

show abstract

Three-dimensional magnetotelluric imaging of the geothermal system beneath the Gonghe Basin, Northeast Tibetan Plateau

Cited by 72 publications

References 27 publications

Lithospheric Structure of a Transitional Magmatic to Amagmatic Continental Rift System—Insights from Magnetotelluric and Local Tomography Studies in the North Tanzanian Divergence, East African Rift

Lithospheric Structure of a Transitional Magmatic to Amagmatic Continental Rift System—Insights from Magnetotelluric and Local Tomography Studies in the North Tanzanian Divergence, East African Rift

Heat Flow Distribution and Thermal Mechanism Analysis of the Gonghe Basin based on Gravity and Magnetic Methods

Mapping of Fault and Hydrothermal System beneath the Seulawah Volcano Inferred from a Magnetotellurics Structure

Contact Info

Product

Resources

About