Key results on deep electrical conductivity anomalies in the Pannonian Basin (PB), and their geodynamic aspects

Ádám, A.; Szarka, L.; Novák, Attila; Wesztergom, Viktor

doi:10.1007/s40328-016-0192-2

Cited by 15 publications

(5 citation statements)

References 25 publications

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“…Korja (2007) investigated the LAB depth beneath Europe based on electrical conductivity estimated with magnetotelluric methods. Similar studies have been conducted in the Pannonian region for a long time (Ádám & Wesztergom, 2001; Ádám et al., 1996), but delimiting the exact LAB depth is not trivial because the values obtained here change in a relatively wide zone (∼45–90 km) into the extensional Pannonian Basin with a thin lithosphere.…”

Section: Discussionsupporting

confidence: 80%

“…This map is based on the review of geophysical data, such as gravity, heat flow, magnetotellurics, seismic studies), which have been revisited. In particular, the study of previous LAB map is based on the inversion of magnetotelluric soundings (Ádám & Wesztergom, 2001; Ádám et al., 1996), heat flow (Lenkey, 1999; Lenkey et al., 2002), early body wave tomographic studies (Babuška & Plomerová, 1988, 1992, 1993; Pajdušák et al., 1989; Wéber, 2000) and gravity measurements (Ádám & Bielik, 1998). Besides previous geophysical constraints, some petrological studies also tackled the lithospheric structure using upper mantle xenoliths from alkali basalts (e.g., Embey‐Isztin, 1976; Embey‐Isztin et al., 2014; Klébesz et al., 2015; Szabó et al., 2004).…”

Section: Introductionmentioning

confidence: 99%

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Lithospheric Structure of the Circum‐Pannonian Region Imaged by S‐To‐P Receiver Functions

Kalmár,

Petrescu,

Stipčević

et al. 2023

Geochem Geophys Geosyst

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The lithosphere‐asthenosphere boundary and mid‐lithospheric discontinuities are primary attributes of the upper mantle. The Pannonian region is an extensional sedimentary basin enclosed by collisional orogens. Here, we estimate the negative phase depth of S‐to‐P receiver functions to image the lithospheric thickness and other discontinuities with high resolution, based on the recent dense seismological broadband networks. The lithosphere‐asthenosphere boundary is relatively shallow (<90 km) in the Pannonian Basin system, and deeper (∼90–140 km) in the surrounding orogens, where average surface heat flow values are higher (120 mW/m2) and lower (50–70 mW/m2), respectively. The 1D and 2D common conversion point migration with 3D velocity model provide comparable but different resolution images beneath the wider region of the Pannonian Basin. We obtained deeper values in the Western (∼120 km) and Southern‐Carpathians orogens (∼135 km). Furthermore, we provide new information on the lithospheric thickness and its seismic properties in the eastern part of the study region (e.g., Apuseni Mountains (∼95 km), Eastern‐Carpathians (∼120 km), Moesian Platform (∼90 km) and Transylvanian Basin (∼85 km). The shallower negative phase depth can be interpreted as the lithosphere‐asthenosphere boundary beneath the Pannonian Basin system in agreement with its high heat flow values. In contrast, the deeper negative phase depth estimates in the colder surroundings can be interpreted as intra‐ or mid‐lithospheric discontinuities, when compared with local seismic tomography models. In this region, the correlation with heat flow implies that the observed negative phase depth is of thermo‐chemical or rheological nature.

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Section: Discussionsupporting

confidence: 80%

Section: Introductionmentioning

confidence: 99%

Lithospheric Structure of the Circum‐Pannonian Region Imaged by S‐To‐P Receiver Functions

Kalmár,

Petrescu,

Stipčević

et al. 2023

Geochem Geophys Geosyst

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“…Estimates for the resistive lithospheric lid thickness from MT data in continents range from ~50–400 km depth, for example, ~60–170 km beneath the Eastern Great Basin and Colorado Plateau (Liu & Hasterok, 2016; Wannamaker et al, 2008), <50–300 km beneath the Yellowstone hot spot area (Kelbert et al, 2012; Zhdanov et al, 2011), ~100–300 km beneath the northern Canada (Jones et al, 2003; Jones et al, 2005), and ~160–250 km beneath cratons in southern Africa (Evans et al, 2011; M. R. Muller et al, 2009). Korja (2007) summarized that the electrical lithospheric lid varies from 45–400 km in Europe, such as 45–100 km thick under the extensional Pannonian Basin (Ádám & Wesztergom, 2001; Cerv et al, 2001) and 150–350 km thick beneath the Fennoscandia (Hjelt et al, 2006; Smirnov & Pedersen, 2009). The electrical LAB is estimated to be 50–80 km in northeastern China (Wei et al, 2008) and 80–120 km in the Qiangtang Terrane, central Tibet (Vozar et al, 2014).…”

Section: Recent Observational Constraints On the Depth And Sharpness ...mentioning

confidence: 99%

The Nature of the Lithosphere‐Asthenosphere Boundary

et al. 2020

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Plate tectonic theory was developed 50 years ago and underpins most of our understanding of Earth's evolution. The theory explains observations of magnetic lineations on the seafloor, linear volcanic island chains, large transform fault systems, and deep earthquakes near deep sea trenches. These features occur through a system of moving plates at the surface of the Earth, which are the surface expression of mantle convection. The plate consists of the chemically distinct crust and some amount of rigid mantle, which move over a weaker mantle beneath. However, exactly where the transition between stronger and weaker mantle occurs and what determines and defines the plate are still debated. In the classic definition the plate is defined thermally, by the geotherm-adiabat intersection, where the plate is the conductively cooling part of the mantle convection system. Many observations such as heat flow, seafloor bathymetry, seismic imaging, and magnetotelluric (MT) imaging are consistent with general lithospheric thickening with age, which suggests that temperature is an important factor in determining lithospheric thickness. However, while age averages give a good indication of overall properties, the range of lithospheric thicknesses reported is large for any given tectonic age interval, suggesting greater complexity. A number of observations including sharp discontinuities from teleseismic scattered waves and active source reflections and also strong anomalies from surface and body wave tomography and MT imaging cannot be explained by a purely thermal model. Another property or process is required to explain the anomalies and sharpen the boundary. Many subsolidus models have been proposed, although none can universally explain the variety of independent global observations. Alternatively, a small amount of partial melt can easily satisfy a range of observations. The presence of melt could also weaken the mantle over geologic timescales, and it would therefore define the lithosphere-asthenosphere boundary (LAB). The location of melt is important to mantle dynamics and the LAB, although exactly where and exactly how much melt exists in the mantle are debated. Asthenospheric melt interpretations include a variety of forms: in small or large melt triangles beneath spreading ridges, in channels, in layers, along a permeability boundary leading to the ridge, at a depth of neutral buoyancy, punctuated, or pervasively over broad areas and either sharply or gradually falling off with depth. This variability in melt character or geometry may explain the previously described variability in LAB depths. The LAB is likely highly variable laterally as are the locations, forms, and amounts of melt, and the LAB is likely dynamic, dictated by small-scale convection and the dynamics of melt generation and migration. A melt-defined, dynamic LAB and a weak asthenosphere have broad implications for our understanding of Earth systems and planetary habitability. A weak asthenosphere caused by volatiles or melt could enable plate tectonic ...

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“…Since the studies by Burov & Cloetingh (2009, 2010), no new attempts have been made to investigate plume‐lithosphere interaction as the driving mechanism for subduction‐like downward movements of the continental lithosphere. This is still the case despite a growing body of robust geophysical data, including observations from seismic tomography and magneto‐telluric sounding in areas such as the Caucasus (Ismail‐Zadeh et al., 2020; Koulakov et al., 2012; Zabelina et al., 2016); Central Asia (He & Santosh, 2018); North‐East China (Kuritani et al., 2019; Li et al., 2020; Wang et al., 2018; Zhang, 2012); Iberia and its margins (Civiero et al., 2019); the Carpathians (e.g., Wortel & Spakman, 2000; Koulakov et al., 2010; Ismail‐Zadeh et al., 2012; Ádám et al., 2017; Petrescu et al., 2019), and the Colorado Plateau (Levander et al., 2011) where upwelling of hot mantle material flanked by downgoing slabs of sinking mantle lithosphere has been recently documented. This makes plume‐induced intra‐continental mantle sinking/foundering a viable and testable mechanism, deserving detailed investigation by means of both modeling and critical analysis of pertinent observations.…”

Section: Subduction Initiation: a Survey Of Mechanisms And Scenariosmentioning

confidence: 99%

Plume‐Induced Sinking of Intracontinental Lithospheric Mantle: An Overlooked Mechanism of Subduction Initiation?

Cloetingh

Koptev

Kovàcs

et al. 2021

Geochem Geophys Geosyst

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Although many different mechanisms for subduction initiation have been proposed, only few of them are viable in terms of consistency with observations and reproducibility in numerical experiments. In particular, it has recently been demonstrated that intra‐oceanic subduction triggered by an upwelling mantle plume could greatly contribute to the onset and operation of plate tectonics in the early and, to a lesser degree, modern Earth. On the contrary, the initiation of intra‐continental subduction still remains underappreciated. Here we provide an overview of 1) observational evidence for upwelling of hot mantle material flanked by downgoing proto‐slabs of sinking continental mantle lithosphere, and 2) previously published and new numerical models of plume‐induced subduction initiation. Numerical modeling shows that under the condition of a sufficiently thick (>100 km) continental plate, incipient downthrusting at the level of the lowermost lithospheric mantle can be triggered by plume anomalies of moderate temperatures and without significant strain‐ and/or melt‐related weakening of overlying rocks. This finding is in contrast with the requirements for plume‐induced subduction initiation within oceanic or thinner continental lithosphere. As a result, plume‐lithosphere interactions within continental interiors of Paleozoic‐Proterozoic‐(Archean) platforms are the least demanding (and thus potentially very common) mechanism for initiation of subduction‐like foundering in the Phanerozoic Earth. Our findings are supported by a growing body of new geophysical data collected in various intra‐continental areas. A better understanding of the role of intra‐continental mantle downthrusting and foundering in global plate tectonics and, particularly, in the initiation of “classic” ocean‐continent subduction will benefit from more detailed follow‐up investigations.

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Key results on deep electrical conductivity anomalies in the Pannonian Basin (PB), and their geodynamic aspects

Cited by 15 publications

References 25 publications

Lithospheric Structure of the Circum‐Pannonian Region Imaged by S‐To‐P Receiver Functions

Lithospheric Structure of the Circum‐Pannonian Region Imaged by S‐To‐P Receiver Functions

The Nature of the Lithosphere‐Asthenosphere Boundary

Plume‐Induced Sinking of Intracontinental Lithospheric Mantle: An Overlooked Mechanism of Subduction Initiation?

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