Paleomagnetism of early Paleozoic volcanic rocks from the Beishan area, Gansu of northwest China: Preliminary insight into early Paleozoic kinemics of the Beishan terrane

2002 ◽  
Vol 47 (18) ◽  
pp. 1561 ◽  
Author(s):  
Baochun HUANG
Keyword(s):  
Volcanic Rocks ◽  
Northwest China ◽  
Early Paleozoic ◽  
Beishan Area ◽  
Insight Into

A new insight into the eastern extension of the Proto-Tethyan margin of Gondwana by Early Paleozoic volcanic rocks in South China

Lithos ◽  
2021 ◽  
pp. 106328
Author(s):  
Yun Zhou ◽  
Shiyu Sun ◽  
Zuohai Feng ◽  
Cheng Xu ◽  
Yongfeng Cai ◽  
...  
Keyword(s):  
South China ◽  
Volcanic Rocks ◽  
Early Paleozoic ◽  
Insight Into

Accommodation of the Cenozoic Tunka Rift Valley at the Ordovician Slyudyanka Collision Zone: insight into volcanic sources, deep-seated inclusions, and seismic tomography models

2020 ◽  
Author(s):  
Tatyana Yasnygina ◽  
Sergei Rasskazov ◽  
Youseph Ailow ◽  
Irina Chuvashova ◽  
Elena Saranina ◽  
...  
Keyword(s):  
Seismic Tomography ◽  
Siberian Craton ◽  
Source Region ◽  
Volcanic Rocks ◽  
Early Paleozoic ◽  
Pb Isotope ◽  
Collision Zone ◽  
The One ◽  
Insight Into ◽  
South Baikal

<p>On the one hand, Pb isotope data on 18–13 Myr volcanic rocks from the eastern part of the Tunka Valley yield age estimate of garnet-bearing source region in the viscous mantle of ca. 2.2 Byr that might correspond to the age of the Siberian craton mantle. On the other hand, inclusions from basanites show the pressure range that overlaps the pressure estimates for rocks of the Slyudyanka Ordovician collision zone. The lithospheric material corresponds to the transition from spinel-pyroxene to olivine-plagioclase facies of peridotites in the uppermost part of the mantle and lower-middle crust. V<sub>S</sub>-data show a low-speed zone dipping from the central Tunka valley eastwards under Southern Baikal to a depth of 70 km. This zone ends at the South Baikal – Tunka Valley junction. We suggest that the eastern parts of the Tunka Valley has inherited the Early Paleozoic collision zone between the Hamar-Daban Terrane and Siberian Paleo-Continent and that the lithosphere of the collision zone overlays the viscous mantle related to the Siberian craton.</p><p>This work is supported by the RSF grant 18-77-10027.</p>

scholarly journals Lower Moscovian limestones of the Bogdashan Range (NW China) as an indicator of cessation of arc magmatism in the Junggar region

2019 ◽  
Vol 27 (1) ◽  
pp. 57-78
Author(s):  
D. V. Alexeiev ◽  
Yu. S. Biske ◽  
A. V. Djenchuraeva ◽  
B. Wang ◽  
O. L. Kossovaya ◽  
...  
Keyword(s):  
Volcanic Rocks ◽  
Foreland Basin ◽  
Northwest China ◽  
Island Arc ◽  
Tien Shan ◽  
Lower Permian ◽  
Carbonate Sediments ◽  
Tropical Zone ◽  
Middle Carboniferous ◽  
Marine Facies

The field revision of the Carboniferous and Lower Permian stratigraphy of the northern Bogdashan (South Junggar, Northwest China) shows that the Lower to Middle Carboniferous island arc volcanic rocks, widely developed in this region, are overlapped everywhere by carbonate and terrigenous-carbonate sediments, containing occasional lava flows and overlain up the section by thick terrigenous series practically devoid of volcanic rocks. The deposition of limestone occurred at the stage of dying off of a volcanic arc, and the question of their age is of fundamental importance for dating this event. Carbonates are represented by facies of lagoons, shoals, and bioherms that formed on the leveled surface of the arc and on the slopes of the last active volcanoes. Bioherms are Waulsortian mounds and are mainly composed of algal limestones and carbonate mud. There are no framestones composed of corals and sponges (chaetetids) typical of the tropical zone. The facies of shallow crinoid-fusulinid limestones typical of the adjacent territories of the Southern Tien Shan and Tarim are poorly represented. Paleogeographically, the position of bioherms corresponds to the northern boundary of the realm of Pennsylvanian reefs. On the basis of foraminifers, brachiopods, and corals, the age of carbonates is early Moscovian (ca. 315–310 Ma). Cessation of island-arc volcanism, followed by the accumulation of limestone in Bogdashan, occurred sub-synchronously with formation of the West Junggar (Bayingou) suture and may reflect docking of the Bogdashan arc to the Yili active margin of the Kazakhstan continent. Further subsidence of Bogdashan and adjacent regions of the Junggar and Turfan basins, which was somewhat slower at the end of the Carboniferous and more intense in the Early and Middle Permian, may reflect the development of the foreland basin that formed along the northern flank of the Tien Shan orogen. Marine facies were locally preserved in this basin until the Artinskian (ca. 285 Ma), and later the Junggar and Turfan basins lost connection to the ocean and developed in continental environments.

Early Paleozoic Volcanism and Metamorphism of the Moretons Harbour–Twillingate Area, Newfoundland

1973 ◽  
Vol 10 (9) ◽  
pp. 1363-1379 ◽  
Author(s):  
D. F. Strong ◽  
J. G. Payne
Keyword(s):  
Oceanic Crust ◽  
Volcanic Rocks ◽  
Metal Sulfides ◽  
Early Paleozoic ◽  
Extensive Area ◽  
Sea Floor ◽  
Pillow Lavas ◽  
Intense Deformation ◽  
Sea Floor Spreading ◽  
Harbour Area

In the Moretons Harbour area, at the eastern end of the Lushs Bight terrane of central Newfoundland, the volcanic rocks of the "Lushs Bight Supergroup" are divided into two new groups, viz, the Moretons Harbour Group and the Chanceport Group. The former is separable into four formations, consisting primarily of variable proportions of basaltic pillow lavas and volcanoclastic sediments, with a composite thickness in excess of 6 km, or around 8 km including an extensive area of 'sheeted' diabase dikes. These formations are steeply dipping and face southwest; they are separated by the Chanceport fault from the Chanceport Group to the south. The latter consists of interbedded basaltic pillow lavas with graywackes and banded red and green cherts, all facing north and steeply dipping to overturned, with a composite thickness of approximately 3 km.The Moretons Harbour Group has been intruded by the Twillingate trondhjemitic granite–granodiorite pluton and abundant basic dikes intrude the granite, indicating that the mafic and felsic magmatism were coeval. Both have undergone intense deformation and the volcanics show a change from greenschist to amphibolite facies mineralogy within a distance of 2 km on approaching the pluton, a result of buttressing by the pluton during deformation, and not an intrusive effect.Base metal sulfides are common throughout the area, but the main occurrences of Cu, As, Sb, and Au are concentrated in the Little Harbour Formation, a 2600 m thick sequence of volcanoclastic rocks within the Moretons Harbour Group.The great thickness of volcanic rocks is interpreted as having formed in an island arc environment, although it is possible that the lowermost parts of the sequence represent oceanic crust. It is unlikely that the sheeted diabases of the Moretons Harbour area were produced by sea-floor spreading.

scholarly journals Geology, Fluid Inclusions and Stable Isotopes of the Xialiugou Polymetallic Deposit in North Qilian, Northwest China: Constraints on its Metallogenesis

Minerals ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 478
Author(s):  
Yongjun Shao ◽  
Huajie Tan ◽  
Guangxiong Peng ◽  
Jiandong Zhang ◽  
Jianzhou Chen ◽  
...  
Keyword(s):  
Fluid Inclusions ◽  
Volcanic Rocks ◽  
Massive Sulfide ◽  
Northwest China ◽  
Polymetallic Deposit ◽  
The North ◽  
Vms Deposits ◽  
Forming Temperature ◽  
North Qilian Orogenic Belt ◽  
North Qilian

The Xialiugou polymetallic deposit is located in the North Qilian Orogenic Belt, Northwest China, of which the main ore-bearing strata are the Middle Cambrian Heicigou Group. The mineralization is zoned with “black” orebodies (galena–sphalerite), which are stratigraphically above the “yellow” orebodies (pyrite–chalcopyrite–tennantite) at the lower zone, corresponding to the alteration assemblages of quartz–sericite in the ore-proximal zone and chlorite in the ore-distal zone. The Xialiugou mineralization can be divided into three stages: (1) Stage I (pyrite); (2) Stage II (chalcopyrite–tennantite–sphalerite); and (3) Stage III (galena–sphalerite). Fluid inclusions data indicate that the physicochemical conditions that lead to ore formation were the medium–low temperature (157–350 °C) and low salinity (0.17–6.87 wt % NaCleqv), and that the ore-forming temperature tended to decrease with the successive mineralization processes. Taking the H–O isotopic compositions (δDV-SMOW = −51.0‰ to −40.5‰, δ18OH2O = −0.4‰ to 8.6‰) into consideration, the ore-forming fluids were most likely derived from seawater with a small amount of magmatic- and meteoric-fluids input. In addition, the combined S (−3.70‰ to 0.10‰) and Pb isotopic (206Pb/204Pb = 18.357 to 18.422, 207Pb/204Pb = 15.615 to 15.687, 208Pb/204Pb = 38.056 to 38.248) data of pyrite indicate that the ore-bearing volcanic rocks may be an important source of ore-forming materials. Finally, we inferred that the Xialiugou deposit shares similarities with the most important volcanogenic massive sulfide (VMS) deposits (Baiyinchang ore field) in China and typical “black ore” type VMS deposits worldwide.

Tectonic affinity of the Alxa Block, Northwest China: Constrained by detrital zircon U–Pb ages from the early Paleozoic strata on its southern and eastern margins

2016 ◽  
Vol 339 ◽  
pp. 289-303 ◽  
Author(s):  
Beihang Zhang ◽  
Jin Zhang ◽  
Yiping Zhang ◽  
Heng Zhao ◽  
Yannan Wang ◽  
...  
Keyword(s):  
Detrital Zircon ◽  
Northwest China ◽  
Early Paleozoic
Sign in / Sign up

Export Citation Format

Share Document