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de Lima Ribeiro A, Fuchs MC, Lorenz S, Röder C, Heitmann J, Gloaguen R. Multi-sensor characterization for an improved identification of polymers in WEEE recycling. Waste Manag 2024; 178:239-256. [PMID: 38417310 DOI: 10.1016/j.wasman.2024.02.024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2023] [Revised: 01/23/2024] [Accepted: 02/15/2024] [Indexed: 03/01/2024]
Abstract
Polymers represent around 25% of total waste from electronic and electric equipment. Any successful recycling process must ensure that polymer-specific functionalities are preserved, to avoid downcycling. This requires a precise characterization of particle compounds moving at high speeds on conveyor belts in processing plants. We present an investigation using imaging and point measurement spectral sensors on 23 polymers including ABS, PS, PC, PE-types, PP, PVC, PET-types, PMMA, and PTFE to assess their potential to perform under the operational conditions found in recycling facilities. The techniques applied include hyperspectral imaging sensors (HSI) to map reflectance in the visible to near infrared (VNIR), short-wave (SWIR) and mid-wave infrared (MWIR) as well as point Raman, FTIR and spectroradiometer instruments. We show that none of the sensors alone can identify all the compounds while meeting the industry operational requirements. HSI sensors successfully acquired simultaneous spatial and spectral information for certain polymer types. HSI, particularly the range between (1600-1900) nm, is suitable for specific identification of transparent and light-coloured (non-black) PC, PE-types, PP, PVC and PET-types plastics; HSI in the MWIR is able to resolve specific spectral features for certain PE-types, including black HDPE, and light-coloured ABS. Fast-acquisition Raman spectroscopy (down to 500 ms) enabled the identification of all polymers regardless their composition and presence of black pigments, however, it exhibited limited capacities in mapping applications. We therefore suggest a combination of both imaging and point measurements in a sequential design for enhanced robustness on industrial polymer identification.
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Affiliation(s)
- Andréa de Lima Ribeiro
- Helmholtz-Zentrum Dresden-Rossendorf, Helmholtz Institute Freiberg for Resource Technology, Freiberg, Chemnitzer Str. 40, 09599 Freiberg, Germany.
| | - Margret C Fuchs
- Helmholtz-Zentrum Dresden-Rossendorf, Helmholtz Institute Freiberg for Resource Technology, Freiberg, Chemnitzer Str. 40, 09599 Freiberg, Germany
| | - Sandra Lorenz
- Helmholtz-Zentrum Dresden-Rossendorf, Helmholtz Institute Freiberg for Resource Technology, Freiberg, Chemnitzer Str. 40, 09599 Freiberg, Germany
| | - Christian Röder
- Institute of Applied Physics, Faculty of Chemistry and Physics, Technische Universität Bergakademie Freiberg, Leipziger Straße 23, 09599 Freiberg, Germany
| | - Johannes Heitmann
- Institute of Applied Physics, Faculty of Chemistry and Physics, Technische Universität Bergakademie Freiberg, Leipziger Straße 23, 09599 Freiberg, Germany
| | - Richard Gloaguen
- Helmholtz-Zentrum Dresden-Rossendorf, Helmholtz Institute Freiberg for Resource Technology, Freiberg, Chemnitzer Str. 40, 09599 Freiberg, Germany
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Booysen R, Jackisch R, Lorenz S, Zimmermann R, Kirsch M, Nex PAM, Gloaguen R. Detection of REEs with lightweight UAV-based hyperspectral imaging. Sci Rep 2020; 10:17450. [PMID: 33060759 PMCID: PMC7562707 DOI: 10.1038/s41598-020-74422-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Accepted: 09/28/2020] [Indexed: 11/09/2022] Open
Abstract
Rare earth elements (REEs) supply is important to ensure the energy transition, e-mobility and ultimately to achieve the sustainable development goals of the United Nations. Conventional exploration techniques usually rely on substantial geological field work including dense in-situ sampling with long delays until provision of analytical results. However, this approach is limited by land accessibility, financial status, climate and public opposition. Efficient and innovative methods are required to mitigate these limitations. The use of lightweight unmanned aerial vehicles (UAVs) provides a unique opportunity to conduct rapid and non-invasive exploration even in socially sensitive areas and in relatively inaccessible locations. We employ drones with hyperspectral sensors to detect REEs at the earth's surface and thus contribute to a rapidly evolving field at the cutting edge of exploration technologies. We showcase for the first time the direct mapping of REEs with lightweight hyperspectral UAV platforms. Our solution has the advantage of quick turn-around times (< 1 d), low detection limits (< 200 ppm for Nd) and is ideally suited to support exploration campaigns. This procedure was successfully tested and validated in two areas: Marinkas Quellen, Namibia, and Siilinjärvi, Finland. This strategy should invigorate the use of drones in exploration and for the monitoring of mining activities.
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Affiliation(s)
- René Booysen
- Helmholtz-Zentrum Dresden-Rossendorf, Helmholtz Institute Freiberg for Resource Technology, 09599, Freiberg, Germany. .,School of Geosciences, University of the Witwatersrand, Johannesburg, 2000, South Africa.
| | - Robert Jackisch
- Helmholtz-Zentrum Dresden-Rossendorf, Helmholtz Institute Freiberg for Resource Technology, 09599, Freiberg, Germany
| | - Sandra Lorenz
- Helmholtz-Zentrum Dresden-Rossendorf, Helmholtz Institute Freiberg for Resource Technology, 09599, Freiberg, Germany
| | - Robert Zimmermann
- Helmholtz-Zentrum Dresden-Rossendorf, Helmholtz Institute Freiberg for Resource Technology, 09599, Freiberg, Germany
| | - Moritz Kirsch
- Helmholtz-Zentrum Dresden-Rossendorf, Helmholtz Institute Freiberg for Resource Technology, 09599, Freiberg, Germany
| | - Paul A M Nex
- School of Geosciences, University of the Witwatersrand, Johannesburg, 2000, South Africa
| | - Richard Gloaguen
- Helmholtz-Zentrum Dresden-Rossendorf, Helmholtz Institute Freiberg for Resource Technology, 09599, Freiberg, Germany
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Rasti B, Ghamisi P, Seidel P, Lorenz S, Gloaguen R. Multiple Optical Sensor Fusion for Mineral Mapping of Core Samples. Sensors (Basel) 2020; 20:E3766. [PMID: 32635611 PMCID: PMC7374339 DOI: 10.3390/s20133766] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Revised: 07/01/2020] [Accepted: 07/02/2020] [Indexed: 11/16/2022]
Abstract
Geological objects are characterized by a high complexity inherent to a strong compositional variability at all scales and usually unclear class boundaries. Therefore, dedicated processing schemes are required for the analysis of such data for mineralogical mapping. On the other hand, the variety of optical sensing technology reveals different data attributes and therefore multi-sensor approaches are adapted to solve such complicated mapping problems. In this paper, we devise an adapted multi-optical sensor fusion (MOSFus) workflow which takes the geological characteristics into account. The proposed processing chain exhaustively covers all relevant stages, including data acquisition, preprocessing, feature fusion, and mineralogical mapping. The concept includes (i) a spatial feature extraction based on morphological profiles on RGB data with high spatial resolution, (ii) a specific noise reduction applied on the hyperspectral data that assumes mixed sparse and Gaussian contamination, and (iii) a subsequent dimensionality reduction using a sparse and smooth low rank analysis. The feature extraction approach allows one to fuse heterogeneous data at variable resolutions, scales, and spectral ranges and improve classification substantially. The last step of the approach, an SVM classifier, is robust to unbalanced and sparse training sets and is particularly efficient with complex imaging data. We evaluate the performance of the procedure with two different multi-optical sensor datasets. The results demonstrate the superiority of this dedicated approach over common strategies.
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Affiliation(s)
- Behnood Rasti
- Helmholtz-Zentrum Dresden-Rossendorf, Helmholtz Institute Freiberg for Resource Technology, Exploration Division, 09599 Freiberg, Germany; (P.G.); (P.S.); (S.L.); (R.G.)
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Sharma SK, Beyer J, Gloaguen R, Heitmann J. Comparing the optical properties and thermal stability of green (TbPO 4), yellow (DyPO 4), and red (PrPO 4) emitting single crystal samples. Phys Chem Chem Phys 2020; 22:10247-10255. [DOI: 10.1039/d0cp01561j] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Blue, green and red-emitting phosphors for near-UV/blue based phosphor blend converted white-light emitting devices have been investigated extensively over the past years.
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Affiliation(s)
- Suchinder K. Sharma
- Institute of Applied Physics
- TU Bergakademie Freiberg
- 09599 Freiberg
- Germany
- Helmholtz-Zentrum Dresden-Rossendorf
| | - Jan Beyer
- Institute of Applied Physics
- TU Bergakademie Freiberg
- 09599 Freiberg
- Germany
| | - Richard Gloaguen
- Helmholtz-Zentrum Dresden-Rossendorf
- Helmholtz Institute Freiberg for Resource Technology
- 09599 Freiberg
- Germany
| | - Johannes Heitmann
- Institute of Applied Physics
- TU Bergakademie Freiberg
- 09599 Freiberg
- Germany
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Sharma SK, Beyer J, Gloaguen R, Heitmann J. Non-quenching photoluminescence emission up to at least 865 K upon near-UV excitation in a single crystal of orange-red emitting SmPO 4. Phys Chem Chem Phys 2019; 21:25669-25677. [PMID: 31729517 DOI: 10.1039/c9cp05663g] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The adjustment of photoluminescence emission spectrum and an enhancement in the thermal stability of red/orange-red emitting phosphors is an important issue for the whole lighting industry. Herein, we present our results on the luminescence spectroscopy of a single crystal sample of SmPO4 exhibiting a prominent orange-red emission at 597 nm, along with a charge-transfer absorption (O2- → Sm3+) around 200 nm. We study the temperature dependence of emission spectra in SmPO4 for excitations at 365 and 455 nm, to mimic experimental conditions for phosphor converted light emitting diodes, to show that the sample has a non-quenching photoluminescence emission up to at least 865 K for an excitation at 365 nm, and ∼865 K for an excitation at wavelength, 455 nm. The thermal stability of SmPO4 was found to be much higher than its structural analogue, EuPO4, which is also an orange-red emission phosphor, but possesses a thermal quenching temperature of 710 K (exc. 365 nm), and 735 K (exc. 455 nm). The extraordinary thermal stability of SmPO4 is a result of the energy transfer from deep defects to the Sm3+ ions at high temperatures. The color purity of SmPO4 (65%) was found to be slightly lower than the EuPO4 sample (70%), at room temperature. The results suggests that the rare earth orthophosphate, SmPO4, has a large potential for near-UV excited phosphor converted solid state lighting devices.
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Affiliation(s)
- Suchinder K Sharma
- Institute of Applied Physics, TU Bergakademie Freiberg, Leipziger Str. 23, 09599 Freiberg, Germany.
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Lorenz S, Seidel P, Ghamisi P, Zimmermann R, Tusa L, Khodadadzadeh M, Contreras IC, Gloaguen R. Multi-Sensor Spectral Imaging of Geological Samples: A Data Fusion Approach Using Spatio-Spectral Feature Extraction. Sensors (Basel) 2019; 19:s19122787. [PMID: 31234309 PMCID: PMC6631011 DOI: 10.3390/s19122787] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/23/2019] [Revised: 06/14/2019] [Accepted: 06/18/2019] [Indexed: 11/20/2022]
Abstract
Rapid, efficient and reproducible drillcore logging is fundamental in mineral exploration. Drillcore mapping has evolved rapidly in the recent decade, especially with the advances in hyperspectral spectral imaging. A wide range of imaging sensors is now available, providing rapidly increasing spectral as well as spatial resolution and coverage. However, the fusion of data acquired with multiple sensors is challenging and usually not conducted operationally. We propose an innovative solution based on the recent developments made in machine learning to integrate such multi-sensor datasets. Image feature extraction using orthogonal total variation component analysis enables a strong reduction in dimensionality and memory size of each input dataset, while maintaining the majority of its spatial and spectral information. This is in particular advantageous for sensors with very high spatial and/or spectral resolution, which are otherwise difficult to jointly process due to their large data memory requirements during classification. The extracted features are not only bound to absorption features but recognize specific and relevant spatial or spectral patterns. We exemplify the workflow with data acquired with five commercially available hyperspectral sensors and a pair of RGB cameras. The robust and efficient spectral-spatial procedure is evaluated on a representative set of geological samples. We validate the process with independent and detailed mineralogical and spectral data. The suggested workflow provides a versatile solution for the integration of multi-source hyperspectral data in a diversity of geological applications. In this study, we show a straight-forward integration of visible/near-infrared (VNIR), short-wave infrared (SWIR) and long-wave infrared (LWIR) data for sensors with highly different spatial and spectral resolution that greatly improves drillcore mapping.
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Affiliation(s)
- Sandra Lorenz
- Division "Exploration Technology", Helmholtz Institute Freiberg for Resource Technology, Helmholtz-Zentrum Dresden-Rossendorf, Chemnitzer Straße 40, 09599 Freiberg, Germany.
| | - Peter Seidel
- Division "Exploration Technology", Helmholtz Institute Freiberg for Resource Technology, Helmholtz-Zentrum Dresden-Rossendorf, Chemnitzer Straße 40, 09599 Freiberg, Germany.
| | - Pedram Ghamisi
- Division "Exploration Technology", Helmholtz Institute Freiberg for Resource Technology, Helmholtz-Zentrum Dresden-Rossendorf, Chemnitzer Straße 40, 09599 Freiberg, Germany.
| | - Robert Zimmermann
- Division "Exploration Technology", Helmholtz Institute Freiberg for Resource Technology, Helmholtz-Zentrum Dresden-Rossendorf, Chemnitzer Straße 40, 09599 Freiberg, Germany.
| | - Laura Tusa
- Division "Exploration Technology", Helmholtz Institute Freiberg for Resource Technology, Helmholtz-Zentrum Dresden-Rossendorf, Chemnitzer Straße 40, 09599 Freiberg, Germany.
| | - Mahdi Khodadadzadeh
- Division "Exploration Technology", Helmholtz Institute Freiberg for Resource Technology, Helmholtz-Zentrum Dresden-Rossendorf, Chemnitzer Straße 40, 09599 Freiberg, Germany.
| | - I Cecilia Contreras
- Division "Exploration Technology", Helmholtz Institute Freiberg for Resource Technology, Helmholtz-Zentrum Dresden-Rossendorf, Chemnitzer Straße 40, 09599 Freiberg, Germany.
| | - Richard Gloaguen
- Division "Exploration Technology", Helmholtz Institute Freiberg for Resource Technology, Helmholtz-Zentrum Dresden-Rossendorf, Chemnitzer Straße 40, 09599 Freiberg, Germany.
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Sharma SK, Köhler T, Beyer J, Fuchs M, Gloaguen R, Heitmann J. Extending the temperature sensing range using Eu3+ luminescence up to 865 K in a single crystal of EuPO4. Phys Chem Chem Phys 2019; 21:16329-16336. [DOI: 10.1039/c9cp03501j] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Extending the temperature sensing range up to 865 K using an appropriate choice of excitation wavelength and coupling scheme in a single crystal sample of EuPO4.
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Affiliation(s)
- Suchinder K. Sharma
- Institute of Applied Physics
- TU Bergakademie Freiberg
- 09599 Freiberg
- Germany
- Helmholtz–Zentrum Dresden–Rossendorf
| | - Thomas Köhler
- Institute of Experimental Physics
- TU Bergakademie Freiberg
- 09599 Freiberg
- Germany
- Helmholtz–Zentrum Dresden–Rossendorf
| | - Jan Beyer
- Institute of Applied Physics
- TU Bergakademie Freiberg
- 09599 Freiberg
- Germany
| | - Margret Fuchs
- Helmholtz–Zentrum Dresden–Rossendorf
- Helmholtz Institute Freiberg for Resource Technology
- 09599 Freiberg
- Germany
| | - Richard Gloaguen
- Helmholtz–Zentrum Dresden–Rossendorf
- Helmholtz Institute Freiberg for Resource Technology
- 09599 Freiberg
- Germany
| | - Johannes Heitmann
- Institute of Applied Physics
- TU Bergakademie Freiberg
- 09599 Freiberg
- Germany
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Sulaymonova VA, Fuchs MC, Gloaguen R, Möckel R, Merchel S, Rudolph M, Krbetschek MR. Feldspar flotation as a quartz-purification method in cosmogenic nuclide dating: A case study of fluvial sediments from the Pamir. MethodsX 2018; 5:717-726. [PMID: 30094201 PMCID: PMC6070659 DOI: 10.1016/j.mex.2018.06.014] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2018] [Accepted: 06/26/2018] [Indexed: 11/16/2022] Open
Abstract
Our flotation cell is built of borosilicate glass, holds up to 90 g of sample, and achieves quartz and feldspar separation in ≤2 h. The procedure uses air bubbles to which the feldspars attach, 0.2% HF to reduce the surface energy of quartz, dodecylamine solution as a feldspar collector, and operates at a pH range of 2.4–2.7 at room temperature. We trace the stepwise enrichment of quartz by X-ray diffraction analysis, which shows that froth flotation is the decisive step to reach 95–100% purity from the initial 23–46%.
Cosmogenic nuclide (CN) dating relies on specific target minerals such as quartz as markers to identify geologic events, including the timing of landscape evolution. The presence of feldspar in sediment samples poses a challenge to the separation of quartz and affects the chemical procedures for extracting the radioactive CNs 10Be and 26Al. Additionally, feldspar contamination reduces the 26Al/27Al ratio, thus hinders the accurate determination of 26Al by accelerator mass spectrometry (AMS). Using fluvial sediment samples from Central Asia, which contain 16–50 weight percent (wt.%) of feldspar, we show that the standard physical separation and chemical cleaning-up procedures for quartz-enrichment reduces the feldspar content to only 9–47 wt.%. We present a new froth flotation mineral-separation device and procedure that allows for very effective quartz enrichment before CN chemistry. Our flotation cell, which has a volume of 600 cm3, is built of borosilicate glass, holds up to 90 g of sample, and achieves quartz and feldspar separation in ≤2 h for very feldspar-rich samples. We trace the stepwise enrichment of quartz to 95–100% purity with our procedure by X-ray diffraction analysis.
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Affiliation(s)
- Vasila A. Sulaymonova
- Geologie, TU Bergakademie Freiberg, Germany
- University of Central Asia, Kyrgyzstan
- Corresponding author at: Geologie, TU Bergakademie Freiberg, Bernhard-von-Cotta-Str. 2, 09599, Freiberg, Germany.
| | - Margret C. Fuchs
- Applied Physics, TU Bergakademie Freiberg, Germany
- Helmholtz-Zentrum Dresden-Rossendorf, Helmholtz Institute Freiberg for Resource Technology, Germany
| | - Richard Gloaguen
- Helmholtz-Zentrum Dresden-Rossendorf, Helmholtz Institute Freiberg for Resource Technology, Germany
| | - Robert Möckel
- Helmholtz-Zentrum Dresden-Rossendorf, Helmholtz Institute Freiberg for Resource Technology, Germany
| | - Silke Merchel
- Helmholtz-Zentrum Dresden-Rossendorf, Helmholtz Institute Freiberg for Resource Technology, Germany
| | - Martin Rudolph
- Helmholtz-Zentrum Dresden-Rossendorf, Helmholtz Institute Freiberg for Resource Technology, Germany
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Ratschbacher L, Krumrei I, Blumenwitz M, Staiger M, Gloaguen R, Miller BV, Samson SD, Edwards MA, Appel E. Rifting and strike-slip shear in central Tibet and the geometry, age and kinematics of upper crustal extension in Tibet. ACTA ACUST UNITED AC 2011. [DOI: 10.1144/sp353.8] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
AbstractThe youngest deformation structures on the Tibet Plateau are about NNE-trending grabens. We first combine remote-sensing structural and geomorphological studies with structural field observations and literature seismological data to study the Muga Purou rift that stretches at c. 86°E across central Tibet and highlight a complex deformation field. ENE-striking faults are dominated by sinistral strike–slip motion; NNE-striking faults have normal kinematics and outline a right-stepping en-echelon array of grabens, also suggesting sinistral strike–slip; along NW-striking fault sets, the arrangement of grabens may indicate a dextral strike–slip component. Thus, in central Tibet, rifts comprise mostly grabens connected to strike–slip fault zones or are arranged en-echelon to accommodate sinistral wrenching; overall strain geometry is constrictional, in which NNE–SSW and subvertical shortening is balanced by WNW–ESE extension. The overwhelmingly shallow earthquakes only locally outline active faults; clusters seem to trace linkage or propagation zones of know structures. The earthquake pattern, the neotectonic mapping, and the local fault–slip analyses emphasize a distributed, heterogeneous pattern of deformation within a developing regional structure and indicate that strain concentration is weak in the uppermost crust of central Tibet. Thus, the geometry of neotectonic deformation is different from that in southern Tibet. Next, we use structural and palaeomagnetic data along the Zagaya section of southern central Tibet to outline significant block rotation and sinistral strike–slip SE of the Muga Purou rift. Our analysis supports earlier interpretations of reactivation of the Bangong–Nujiang suture as a neotectonic strike–slip belt. Then, we review the existing and provide new geochronology on the onset of neotectonic deformation in Tibet and suggest that the currently active neotectonic deformation started c. 5 Ma ago. It was preceded by c. north–south shortening and c. east–west lengthening within a regime that comprises strike–slip and low-angle normal faults; these were active at c. 18–7 Ma. The c. east-striking, sinistral Damxung shear zone and the c. NE-trending Nyainqentanghla sinistral-normal detachment allow speculations about the nature of this deformation: the ductile, low-angle detachments may be part of or connect to a mid-crustal décollement layer in which the strike–slip zones root; they may be unrelated to crustal extension. Finally, we propose a kinematic model that traces neotectonic particle flow across Tibet and speculate on the origin of structural differences in southern and central Tibet. Particles accelerate and move eastwards from western Tibet. Flow lines first diverge as the plateau is widening. At c. 92°E, the flow lines start to converge and particles accelerate; this area is characterized by the appearance of the major though-going strike–slip faults of eastern-central Tibet. The flow lines turn southeastward and converge most between the Assam–Namche Barwa and Gongha syntaxes; here the particles reach their highest velocity. The flow lines diverge south of the cord between the syntaxes. This neotectonic kinematic pattern correlates well with the decade-long velocity field derived from GPS-geodesy. The difference between the structural geometries of the rifts in central and southern Tibet may be an effect of the basal shear associated with the subduction of the Indian plate. The boundary between the nearly pure extensional province of the southern Tibet and the strike–slip and normal faulting one of central Tibet runs obliquely across the Lhasa block. Published P-wave tomographic imaging showed that the distance over which Indian lithosphere has thrust under Tibet decreases from west to east; this suggests that the distinct spatial variation in the mantle structure along the collision zone is responsible for the surface distribution of rift structures in Tibet.Supplementary material:Containing supporting data is available at http://www.geolsoc.org.uk/SUP18446.
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Affiliation(s)
- Lothar Ratschbacher
- Geowissenschaften, Technische Universität Bergakademie Freiberg, 09599 Freiberg, Germany
| | - Ingrid Krumrei
- Geowissenschaften, Technische Universität Bergakademie Freiberg, 09599 Freiberg, Germany
| | - Marli Blumenwitz
- Geologie, Abteilung Geophysik, Universität Tübingen, 72076 Tübingen, Germany
| | - Martin Staiger
- Geologie, Abteilung Geophysik, Universität Tübingen, 72076 Tübingen, Germany
| | - Richard Gloaguen
- Geowissenschaften, Technische Universität Bergakademie Freiberg, 09599 Freiberg, Germany
| | - Brent V. Miller
- Earth Sciences, Syracuse University, Syracuse, NY 13244-1070, USA
- Geosciences, Texas A&M University, College Station, TX 77843-3148, USA
| | - Scott D. Samson
- Earth Sciences, Syracuse University, Syracuse, NY 13244-1070, USA
| | - Michael A. Edwards
- Geowissenschaften, Technische Universität Bergakademie Freiberg, 09599 Freiberg, Germany
| | - Erwin Appel
- Geologie, Abteilung Geophysik, Universität Tübingen, 72076 Tübingen, Germany
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