Geomorphology and geochemistry of the late Cenozoic volcanoes in the Halaha River-Chaoer River volcanic fields, western Greater Hinggan Mountain Range, NE China

2021 ◽  
pp. SP510-2020-82
Author(s):  
Yong-Wei Zhao ◽  
Haibo Zou ◽  
Ni Li

AbstractThe Halaha River-Chaoer River (HC) volcanic field in the Greater Hinggan Mountain Range (NE China) consists of at least 41 monogenetic basaltic volcanoes. Strombolian, violent Strombolian, and phreatomagmatic eruptions, as well as the transitional eruptions, generated simple volcanic cone (single vent) and composite volcanic cone (multiple vents). Simple elongated cone is the most abundant geomorphology type. By analyzing the elongated crater and coalescent aligned circular crater, cone breaching and depression, and aligned vents, we identified a number of magma-feeding fissures. The majority of these fissures strike NE-ENE. Accordingly, we infer that the regional stress field affected volcanism in the HC field. The lavas in this field are alkali basalts that are enriched in light rare earth elements (La/YbN = 7.9 to 24.5). Their OIB-like REE and spider-diagram patterns, high Nb/U ratios, and high TiO2 contents (> 2 wt. %) indicate that the basalts were derived from the asthenosphere mantle. Both the asthenosphere upwelling and the tectonic forces are the key controlling factors of the volcanism in the HC field.Supplementary material at https://doi.org/10.6084/m9.figshare.c.5355233

2021 ◽  
pp. SP510-2020-137
Author(s):  
Xiang Bai ◽  
Wei Wei ◽  
Hongmei Yu ◽  
Zhengquan Chen

AbstractThe Cenozoic alkali basalts are widely exposed in the Jingpohu volcanic field, Northeast China. Previous volcanology and geochronology researches have revealed that they were formed in three periods of Miocene (∼29.23-13.59 Ma), Pleistocene (∼83.7 Ka), and Holocene (∼5500-5200 a BP). The Miocene and Pleistocene basalts consist of alkali olivine basalts, while the Holocene basalts are composed of alkali olivine basalts and leucite tephrites. Petrogenetic studies reveal that the primary magmas of the Miocene and Pleistocene alkali olivine basalts originated from partial melting of EM2-like garnet peridotites, and those of the Holocene alkali olivine basalts were derived from melting of EM1- and EM2-like garnet peridotites with higher garnet proportions. In contrast, the primary magmas of Holocene leucite tephrites were derived from melting of eclogites and peridotites. Combined with previous researches, we suggest that melting of the mantle source region to generate Jingpohu alkali basalts was triggered by decarbonization and dehydration of the slabs stagnated in the mantle transition zone.Supplementary material at https://doi.org/10.6084/m9.figshare.c.5227666


2020 ◽  
Vol 177 (5) ◽  
pp. 1039-1056
Author(s):  
Thomas B. Phillips ◽  
Craig Magee

Intraplate volcanism is widely distributed across the continents, but the controls on the 3D geometry and longevity of individual volcanic systems remain poorly understood. Geophysical data provide insights into magma plumbing systems, but, as a result of the relatively low resolution of these techniques, it is difficult to evaluate how magma transits highly heterogeneous continental interiors. We use borehole-constrained 2D seismic reflection data to characterize the 3D geometry of the Tuatara Volcanic Field located offshore New Zealand's South Island and investigate its relationship with the pre-existing structure. This c. 270 km2 field is dominated by a dome-shaped lava edifice, surrounded and overlain by c. 69 volcanoes and >70 sills emplaced over 40 myr from the Late Cretaceous to Early Eocene (c. 85–45 Ma). The Tuatara Volcanic Field is located above a basement terrane boundary represented by the Livingstone Fault; the recently active Auckland Volcanic Field is similarly located along-strike on North Island. We suggest that the Livingstone Fault controlled the location of the Tuatara Volcanic Field by producing relief at the base of the lithosphere, thereby focussing lithospheric detachment over c. 40 myr, and provided a pathway that facilitated the ascent of magma. We highlight how observations from ancient intraplate volcanic systems may inform our understanding of active intraplate volcanic systems, including the Auckland Volcanic Field.Supplementary material: Interpreted seismic section showing well control on stratigraphic interpretation is available at https://doi.org/10.6084/m9.figshare.c.5004464


2020 ◽  
pp. SP510-2020-45
Author(s):  
Hongmei Yu ◽  
Bo Zhao ◽  
Zhengquan Chen ◽  
Haiquan Wei ◽  
Wenjian Yang ◽  
...  

AbstractThe Tengchong Volcanic Field (TVF) is one of the youngest volcanic areas in China, and located in the southwestern part of Yunnan Province, China, adjacent to the collision zone between the Indian Plate and Eurasian Plate. This paper summarizes the results of previous research on the eruption history, petrochemistry, and geodynamic background of the TVF and presents a detailed analysis of the available data. Eruptions took place from the Pliocene to the Holocene and were divided into five stages. The composition of the magma went through two cycles: the N2-Q1 P-Q2 P volcanic rocks went through the evolutionary process from basalt to dacite and the Q3 P-Qh magma evolved from trachybasalt to trachyte. The evolution of magma is mainly related to the crystallisation and separation of pyroxene and ilmenite. The mantle source area of the TVF volcanic rocks was caused by the mixing between the MORB-source mantle and the eastern Indian continental margin sediments (EIS) to different degree. Geophysical data also showed that the Indian Plate has been subducted under the TVF area. There are also magma chambers in the crust within a depth of 25 km in the TVF that are replenished by mantle magma.Supplementary material at https://doi.org/10.6084/m9.figshare.c.5227663


2021 ◽  
pp. SP510-2020-132
Author(s):  
Bo Zhao ◽  
Feixiang Wei ◽  
Wenjian Yang ◽  
Jiandong Xu ◽  
Xiaoge Cui

AbstractIn the West Kunlun Mountains, four volcanic fields (i.e., Kangxiwa, Dahongliutan, Qitaidaban, and Quanshuigou) are distributed along the Dahongliutan fault, which is approximately 180 km long. Based on field investigations, chronological measurements, and geochemical analysis of some volcanic fields, the results of geological, geochemical, and geophysical research by the predecessors in the corresponding study areas are summarised. The volcanic activities in these areas were mainly effusive eruptions, explosive eruptions, and phreatomagmatic eruptions. In this study, we discovered the Qitaiyanhu volcanic field for the first time and determined that the 14C age of the lacustrine strata underlying the Qitaiyanhu lava flows are 13110 ± 40 a B.P., indicating that there may still have been volcanic activities in the late Pleistocene and even the Holocene in the Dahongliutan fault area. The base surge deposits, which are the products of the interaction between magma and water, were found in the Kangxiwa volcanic field. The four shoshonitic rock fields of Kangxiwa, Dahongliutan, Qitaidaban, and Quanshuigou are likely to be products of different evolution stages from the same magma source area. The magmatic origin of these volcanic fields may be related to the upwelling of the asthenosphere, triggered by the collision between the Indian and Tarim plates.Supplementary material at https://doi.org/10.6084/m9.figshare.c.5353446


2021 ◽  
pp. SP510-2020-67
Author(s):  
Zhengquan Chen ◽  
Yongwei Zhao ◽  
Xiang Bai ◽  
Wei Wei ◽  
Yongshun Liu ◽  
...  

AbstractCombined geologic, geochronologic, and geophysical data demonstrate that the evolution of the Wudalianchi Volcanic Field is closely linked to the most recent tectonic movements affecting the Songliao Basin, driven by dynamics associated with the subducting slab of the Pacific Plate. Intense volcanic activity has occurred in the Wudalianchi since the middle Pleistocene, including historical eruptions in 1720, 1721, and 1776. Together with radiometric age data, variations in the geomorphology of the volcanic cones reflect the effects of multiple eruptions at the same locations but during different periods. Geophysical data-including seismic images, tomography, and magneto-telluric profiles-suggest the existence of subsurface low-resistivity bodies beneath some of the volcanoes, posing the potential that these could reactivate and erupt again in the future. To better characterize and elucidate the magmatic and volcanic processes operative in the WDLC over geologic time, it is essential to conduct systematic geochemical and isotopic studies of many more samples of eruptive product, especially those from the older, single volcanoes.Supplementary material at https://doi.org/10.6084/m9.figshare.c.5260046


2020 ◽  
pp. SP510-2020-133
Author(s):  
Jiandong Xu ◽  
Bo Zhao ◽  
Hongmei Yu ◽  
Feixiang Wei ◽  
Zhengquan Chen

AbstractAshikule volcanic field, developed in the western Kunlun mountain of north Tibet, is composed with about 10 volcanoes, and covers a total area of about 200km2 at the average altitude around 5,000m, one of the highest volcanic field in the world. In this study, we conducted detailed field investigation of geological and geomorphological features of volcanic rocks and volcanic edifices in Ashikule basin, and compiled large-scaled geologic map of the study area for the first time. We also collected series of samples to conduct petrochemistry analysis, as well as high-precision 40Ar/39Ar geochronology study of selected lavas from Ashikule volcanic field. Finally, we refined the eruption history for the volcanic activity in the basin, which provides some new volcanological evidence for the study of tectonic evolution of the Northern Tibetan Plateau.Supplementary material at https://doi.org/10.6084/m9.figshare.c.5227665


2021 ◽  
pp. SP520-2021-144
Author(s):  
Marie-Noëlle Guilbaud ◽  
Corentin Chédeville ◽  
Ángel Nahir Molina-Guadarrama ◽  
Julio Cesar Pineda-Serrano ◽  
Claus Siebe

AbstractThe eruption of the ∼10 km3 rhyolitic Las Derrumbadas twin domes about 2000 yrs ago has generated a wide range of volcano-sedimentary deposits in the Serdán-Oriental lacustrine basin, Trans-Mexican Volcanic Belt. Some of these deposits have been quarried, creating excellent exposures. In this paper we describe the domes and related products and interpret their mode of formation, reconstructing the main phases of the eruption as well as syn-and-post eruptive erosional processes. After an initial phreatomagmatic phase that built a tuff ring, the domes grew as an upheaved plug lifting a thick sedimentary pile from the basin floor. During uplift, the domes collapsed repeatedly to form a first-generation of hetero-lithologic hummocky debris avalanche deposits. Subsequent dome growth produced a thick talus and pyroclastic density currents. Later, the hydrothermally-altered over-steepened dome peaks fell to generate 2nd generation, mono-lithologic avalanches. Subsequently, small domes grew in the collapse scars. From the end of the main eruptive episode onwards, heavy rains remobilized parts of the dome carapaces and talus, depositing lahar aprons. Las Derrumbadas domes are still an important source of sediments in the basin, and ongoing mass-wasting processes are associated with hazards that should be assessed, given their potential impact on nearby populations.Supplementary material at https://doi.org/10.6084/m9.figshare.c.5752296


2021 ◽  
pp. jgs2021-035
Author(s):  
Wanchese M. Saktura ◽  
Solomon Buckman ◽  
Allen P. Nutman ◽  
Renjie Zhou

The Jurassic–Cretaceous Tsoltak Formation from the eastern borderlands of Ladakh Himalaya consists of conglomerates, sandstones and shales, and is intruded by norite sills. It is the oldest sequence of continent-derived sedimentary rocks within the Shyok Suture. It also represents a rare outcrop of the basement rocks to the voluminous Late Cretaceous–Eocene Ladakh Batholith. The Shyok Formation is a younger sequence of volcaniclastic rocks that overlie the Tsoltak Formation and record the Late Cretaceous closure of the Mesotethys Ocean. The petrogenesis of these formations, ophiolite-related harzburgites and norite sill is investigated through petrography, whole-rock geochemistry and U–Pb zircon geochronology. The youngest detrital zircon grains from the Tsoltak Formation indicate Early Cretaceous maximum depositional age and distinctly Gondwanan, Lhasa microcontinent-related provenance with no Eurasian input. The Shyok Formation has Late Cretaceous maximum depositional age and displays a distinct change in provenance to igneous detritus characteristic of the Jurassic–Cretaceous magmatic arc along the southern margin of Eurasia. This is interpreted as a sign of collision of the Lhasa microcontinent and the Shyok ophiolite with Eurasia along the once continuous Shyok–Bangong Suture. The accreted terranes became the new southernmost margin of Eurasia and the basement to the Trans-Himalayan Batholith associated with the India-Eurasia convergence.Supplementary material:https://doi.org/10.6084/m9.figshare.c.5633162


2021 ◽  
pp. geochem2021-074
Author(s):  
Godson Godfray

Successful gold exploration projects depend on a piece of clear information on the association between gold, trace elements, and mineralization controlling factors. The use of soil geochemistry has been an important tool in pinpointing exploration targets during the early stage of exploration. This study aimed to establish the gold distribution, the elemental association between gold and its pathfinder elements such as Cu, Zn, Ag, Ni, Co, Mn, Fe, Cd, V, Cr, Ti, Sc, In, and Se and identify lithologies contributing to the overlying residual soils. From cluster analysis, a high similarity level of 53.93% has been shown with Ag, Cd, and Se at a distance level of 0.92. Au and Se have a similarity level of 65.87% and a distance level of 0.68, hence is proposed to be the most promising pathfinder element. PCA, FA, and the Pearson's correlation matrix of transformed data of V, Cu, Ni, Fe, Mn, Cr, and Co and a stronger correlation between Pb and U, Th, Na, K, Sn, Y, Ta and Be shows that source gold mineralization might be associated with both hornblende gneisses interlayered with quartzite, tonalite, and tonalitic orthogneiss. From the contour map and gridded map of Au and its pathfinder elements, it has been noted that their anomalies and target generated are localized in the Northern part of the area. The targets trend ESE to WNW nearly parallel to the shear zones as a controlling factor of Au mineralization emplacement.Supplementary material:https://doi.org/10.6084/m9.figshare.c.5721965


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