Article
Geosciences, Multidisciplinary
Iva Lihter, Kyle P. Larson, Sudip Shrestha, John M. Cottle
Summary: The metamorphic core of the Himalayan orogen is divided into multiple packages by structural discontinuities. The scarcity of field evidence impedes the identification of these structures and hinders our understanding of their role in the development of the Himalaya. This study characterizes the metamorphic and geochronological history of garnet-, sillimanite- and kyanite-bearing gneisses in the Makalu-Arun region, Nepal. It identifies four rock packages with distinct metamorphic histories separated by thrust-sense structures.
JOURNAL OF THE GEOLOGICAL SOCIETY
(2023)
Article
Geosciences, Multidisciplinary
Lei Zhang, Bo Zhang, Jinjiang Zhang, Jiamin Wang, Fulong Cai, Zhongbao Zhao, Siyu Chen, Xiaorong Li
Summary: Deformation processes and rheological changes within the South Tibetan Detachment System (STDS) were studied to quantify the spatial and temporal variations of the shear zone's internal deformation and rheology properties. The results show that strain localization occurred within the STDS, and the strain rates and viscosities were calculated. The estimated viscosities are compatible with the channel flow model for exhumation, and this study contributes to a better understanding of the exhumation process in the Himalayas.
JOURNAL OF STRUCTURAL GEOLOGY
(2022)
Review
Geosciences, Multidisciplinary
Priyadarshi Chowdhury, Sumit Chakraborty, Taras Gerya
Summary: The evolution of metamorphic rocks in terms of pressure, temperature, and time is directly tied to geodynamics, with different tectonic settings showing variations in their thermal architecture. The association between P-T paths and thermobaric ratios of metamorphic rocks is commonly used to distinguish different tectonic domains. However, the significance of metamorphic timescales in constraining tectonic settings is often overlooked. The relationship between the thermal regime, rheology, and rates of motion controlled by heat, mass, and momentum conservation laws results in differences in heating, cooling, burial, exhumation rates of metamorphic rocks, ultimately influencing the duration of metamorphism.
Article
Geochemistry & Geophysics
Muhammad Qasim, Javed Iqbal Tanoli, Luqman Ahmad, Lin Ding, Qasim Ur Rehman, Umbreen Umber
Summary: This study conducted a detrital zircon provenance investigation of sandstones from the Kamlial Formation in the Kashmir Basin, revealing a dominant age population around 400-1200 Ma and a minor population around 1600-1900 Ma, with scattered ages between 2000 and 3000 Ma. The presence of younger ages (<150 Ma) in the samples indicates an Asian provenance. The age pattern of detrital zircons strongly resembles Himalayan sources, suggesting a mixed provenance for the Kamlial Formation. The study also proposes a tectonic model involving large-scale exhumation in the Himalaya due to Panjal thrust activation during the deposition of the Kamlial Formation.
Article
Geosciences, Multidisciplinary
Myo Min, Lothar Ratschbacher, Leander Franz, Bradley R. Hacker, Eva Enkelmann, Eko Yoan Toreno, Birk Haertel, Bernd Schurr, Marion Tichomirowa, Joerg A. Pfaender
Summary: In this study, lithologic tracers and data on pressure, temperature, deformation, and time were used to investigate the geological events that occurred in the Katha Range of central Myanmar. The researchers found Cambro-Ordovician rocks with Indian affinity, which are related to rocks in Tibet and the Himalayas. The study also revealed the metamorphism, exhumation/cooling, and tectonic processes of collision and subduction in the region.
GEOPHYSICAL RESEARCH LETTERS
(2022)
Article
Geochemistry & Geophysics
Beatriz Benetti, Chiara Montomoli, Salvatore Iaccarino, Antonio Langone, Rodolfo Carosi
Summary: The newly identified Badrinath shear zone (BSZ) in the Garhwal Himalaya of NW India plays a significant role in the evolution of the Greater Himalayan Sequence (GHS), with rocks experiencing various metamorphic processes and shear activities.
Article
Geosciences, Multidisciplinary
Xiaoyu Chen, Junlai Liu, Jean-Pierre Burg, Jiaxin Yan, Baojun Zhou, Hongshuai Shan, Xiaoxi Bao, Wenkui Fan, Jian Zhang, Chunru Hou
Summary: This study focuses on the extrusion mechanism of the Sundaland block in the southeastern Tibetan Plateau. Through structural and kinematic analysis, timing of shearing, and thermal history reconstruction, the researchers reveal the tectonic processes driving the deformation of metamorphic complexes in the area. The study finds that Cenozoic dome structures are widely distributed, with high-grade metamorphic rocks in the cores and low-grade metamorphism and deformation in the mantles. Kinematic indicators and thermochronological data suggest that the formation and exhumation of the dome structures were associated with middle and lower crustal flow during the extrusion of the Sundaland block.
EARTH-SCIENCE REVIEWS
(2023)
Article
Geosciences, Multidisciplinary
Subhajit Ghosh, Nibir Mandal, Sreetama Roy, Santanu Bose
Summary: This study identifies a change in ductile deformation modes and the formation of the Main Central Thrust (MCT) zone in the Himalayan Crystalline Complex (HCC) based on field and microstructural evidence. The HCC initially experienced distributed ductile strains before a transition to localized deformation at approximately 16 Ma. The MCT zone marks a boundary between the hot HCC and the colder Lesser Himalayan terrane, with a thickness of 4-6 km. The study also presents a tectonic model for the evolution of the Higher Himalaya based on previous laboratory findings.
JOURNAL OF STRUCTURAL GEOLOGY
(2023)
Article
Geosciences, Multidisciplinary
Subhajit Ghosh, Nibir Mandal, Sreetama Roy, Santanu Bose
Summary: This study investigates the transition in the modes of ductile deformation across the Himalayan Crystalline Complex (HCC) and the formation of the Main Central Thrust (MCT) zone. The HCC experienced distributed ductile strains prior to-16 Ma, resulting in planar fabrics and folds. At-16 Ma, there was a tectonic transition to localized deformation and the formation of the MCT zone. This study presents field data and a conceptual tectonic model to understand the tectono-thermal evolution of the Higher Himalaya.
JOURNAL OF STRUCTURAL GEOLOGY
(2023)
Article
Geography, Physical
Mahesh Thakur, Gurvinder Singh, Javed N. Malik
Summary: This paper reports geomorphic signatures of neotectonic activity along Himalayan Frontal Thrust (HFT) in the area around Nahan Salient using remote sensing and field investigations, highlighting newly discovered exposures of HFT fault zone and active fault traces at Khetpurali. The study demonstrates the non-blind nature of the HFT fault zone at Khetpurali, with variable geometry and the presence of fault-propagation-fold structures, indicating implications for seismic hazard in the Nahan Salient.
QUATERNARY INTERNATIONAL
(2021)
Article
Geology
T. G. Zhao, Q. L. Hou, M. Y. Shi, L. Ding
Summary: The study of the Dashuiyu ductile shear zone reveals the deformation process and structural significance of the shear zone through analysis of deformation temperature, finite strain, and kinematic vorticity. The results show that the shear zone is affected by flattening and controlled by pure shear during formation. The study indicates that magmatism plays a dominant role in the formation of the Yunmengshan metamorphic core complex, with the detachment process of the northeast segment of the Dashuiyu ductile shear zone being obstructed by the eastern rock mass.
ACTA PETROLOGICA SINICA
(2021)
Article
Geosciences, Multidisciplinary
Dyuti Prakash Sarkar, Jun-ichi Ando, Akihiro Kano, Hirokazu Kato, Gautam Ghosh, Kaushik Das
Summary: It is crucial to determine the temperature and depth of formation of fault rocks in order to understand their rheology, exhumation, and evolution. This study demonstrates the applicability of the carbonate clumped isotope thermometer in low-grade carbonate-bearing fault rocks, providing more accurate temperature and depth constraints for fault zones. The integration of analytical techniques can promote the application of calcite-based clumped isotope thermometry in fault zone processes and help refine shallow crustal fault zone models.
PROGRESS IN EARTH AND PLANETARY SCIENCE
(2021)
Review
Geosciences, Multidisciplinary
Nusrat Nazir, Ramamoorthy Ayyamperumal, Khawaja Umair Majeed, Zhang Chengjun
Summary: The mineralization in this area is closely related to the shoshonitic Niuxinshan meddling complex (NIC), and the structural change may have occurred between 155 and 185 Ma. According to geochronological and geochemical data, the mineralization is Late Jurassic (155 Ma).
GEOLOGICAL JOURNAL
(2022)
Article
Geosciences, Multidisciplinary
Takeshi Imayama, Ryuhei Hoshino, Keewook Yi, Ryoichi Kawabata
Summary: This study presents the P-T-t path of the Ilam Nappe and establishes its correlation with the lower-middle High Himalayan Crystalline Sequence hinterland. The results indicate that the formation and evolution of the Ilam Nappe are associated with crustal thickening and overthrusting.
JOURNAL OF ASIAN EARTH SCIENCES
(2022)
Article
Geosciences, Multidisciplinary
Aranya Sen, Alosree Dey, Koushik Sen
Summary: This study investigates the geochemistry, geochronology, and metamorphic modeling of garnet-amphibolite in the Western Garhwal Himalaya region of India. The results suggest that the garnet-amphibolite represents the pre-Himalayan Indian lower crust and underwent high-pressure metamorphism during the Himalayan orogeny under high-pressure and medium-temperature conditions.
GEOLOGICAL JOURNAL
(2023)
Article
Geosciences, Multidisciplinary
Riccardo Graziani, Chiara Montomoli, Salvatore Iaccarino, Luca Menegon, Laura Nania, Rodolfo Carosi
GEOLOGICAL MAGAZINE
(2020)
Article
Geochemistry & Geophysics
M. Simonetti, R. Carosi, C. Montomoli, J. M. Cottle, R. D. Law
Article
Dentistry, Oral Surgery & Medicine
M. Simonetti, R. Carosi, C. Montomoli, R. D. Law, J. M. Cottle
Summary: Shear zone behavior is controlled by deformation regime, temperature, strain rate, and rheology of rocks. Differential strain may lead to deformation localization or migration into wall-rocks, affecting shear zone thickness. The Ferriere-Mollieres Shear Zone in the Western Alps provides insight into deformation processes and can serve as a valuable research area for studying large-scale shear zones.
JOURNAL OF ORAL AND MAXILLOFACIAL SURGERY
(2021)
Article
Geosciences, Multidisciplinary
Laura Nania, Chiara Montomoli, Salvatore Iaccarino, Gianfranco Di Vincenzo, Rodolfo Carosi
Summary: This study focuses on the static micas in the hanging wall of the South Tibetan Detachment System (STDS) and uses geochronological 40Ar/39Ar analyses and microstructural data to determine the timing of static (re)crystallization of these micas, as well as hypothesizing a kinematic link to a late thermal event in the central Himalaya. Homogeneous chemical compositions and ages were found in the micas, suggesting a late thermal event after ductile activity ceased in the shear zone.
JOURNAL OF THE GEOLOGICAL SOCIETY
(2022)
Article
Geochemistry & Geophysics
Beatriz Benetti, Chiara Montomoli, Salvatore Iaccarino, Antonio Langone, Rodolfo Carosi
Summary: The newly identified Badrinath shear zone (BSZ) in the Garhwal Himalaya of NW India plays a significant role in the evolution of the Greater Himalayan Sequence (GHS), with rocks experiencing various metamorphic processes and shear activities.
Article
Geography
A. Petroccia, C. Montomoli, S. Iaccarino, R. Carosi
Summary: This study deciphers the structural evolution of a sector in the Sardinian Variscan Belt, highlighting the polyphasic evolution under low-grade metamorphic conditions. It provides insights into the geological history of the region during the Variscan orogeny.
Article
Geosciences, Multidisciplinary
Alessandro Petroccia, Rodolfo Carosi, Chiara Montomoli, Salvatore Iaccarino, Alberto Vitale Brovarone
Summary: This study presents new thermal data obtained from Raman Spectroscopy on Carbonaceous Material (RSCM) in the low-grade metamorphic rocks of the hinterland-foreland transition zone in the Variscan belt of Sardinia. The results suggest that the internal and external nappes experienced different degrees of metamorphism and additional heating along the tectonic boundary, followed by regional-scale folding.
Article
Geosciences, Multidisciplinary
Rodolfo Carosi, Chiara Montomoli, Salvatore Iaccarino, John M. Cottle, Hans-Joachim Massonne, Laura Nania, Matteo Simonetti
Summary: Through structural analysis, petrochronology and metamorphic petrology, the timing of a high-temperature ductile shear zone (Jagat Shear Zone) in the Himalayan metamorphic core in Central-Western Nepal has been identified and constrained. The establishment of the age of this shear zone, as well as its connection with the Main Central Thrust activity, fills a gap in understanding the distribution and internal structure of the Himalayan metamorphic core. This study is a significant step towards a precise identification of the burial, assembly and exhumation mechanisms of the core.
GEOLOGICAL MAGAZINE
(2023)
Article
Geosciences, Multidisciplinary
Rodolfo Carosi, Chiara Montomoli, Salvatore Iaccarino, Beatriz Benetti, Alessandro Petroccia, Matteo Simonetti
Summary: In this article, a combined structural and geochronological approach is used to study two major regional shear zones, revealing the timing of their activity and their impact on the orogenic evolution.