Geochemistry and Nd isotopes of Lower Permian siliciclastic rocks from central Tibet, western China: Evidence for Early Permian initiation of the rifting between the Lhasa and Qiangtang blocks?

2020 ◽  
Vol 55 (4) ◽  
pp. 2915-2929
Author(s):  
Li‐Long Yan ◽  
Lu Zeng ◽  
Yang Wang ◽  
Xian‐Chun Tang
Keyword(s):  
Western China ◽  
Lower Permian ◽  
Early Permian ◽  
Nd Isotopes ◽  
Siliciclastic Rocks ◽  
Central Tibet

Nd isotopes of siliciclastic rocks from Tibet, western China: Constraints on provenance and pre-Cenozoic tectonic evolution

2007 ◽  
Vol 256 (3-4) ◽  
pp. 604-616 ◽  
Author(s):  
Kai-Jun Zhang ◽  
Yu-Xiu Zhang ◽  
Bing Li ◽  
Li-Feng Zhong
Keyword(s):  
Tectonic Evolution ◽  
Western China ◽  
Nd Isotopes ◽  
Siliciclastic Rocks

Newly discovered eclogites from the Bangong Meso–Tethyan suture zone (Gaize, central Tibet, western China): mineralogy, geochemistry, geochronology, and tectonic implications

2015 ◽  
Vol 58 (5) ◽  
pp. 574-587 ◽  
Author(s):  
Yu-Xiu Zhang ◽  
Zhi-Wu Li ◽  
Li-Dong Zhu ◽  
Kai-Jun Zhang ◽  
Wen-Guang Yang ◽  
...  
Keyword(s):  
Suture Zone ◽  
Western China ◽  
Tectonic Implications ◽  
Central Tibet

scholarly journals Charcoal remains from a tonstein layer in the Faxinal Coalfield, Lower Permian, southern Paraná Basin, Brazil

2011 ◽  
Vol 83 (2) ◽  
pp. 471-481 ◽  
Author(s):  
André Jasper ◽  
Dieter Uhl ◽  
Margot Guerra-Sommer ◽  
Abdalla M. B Abu Hamad ◽  
Neli T. G Machado
Keyword(s):  
Lower Permian ◽  
Published Data ◽  
Early Permian ◽  
Ash Fall ◽  
Potential Source ◽  
Volcanic Events ◽  
Paraná Basin ◽  
Surrounding Areas ◽  
Parana Basin

Fossil charcoal has been discovered in the Faxinal Coalfield, Early Permian, Rio Bonito Formation, in the southernmost portion of the Paraná Basin, Brazil. Three types of pycnoxylic gymnosperm woods recovered from a single tonstein layer are described and confirm the occurrence of paleowildfire in this area. A decrease of the charcoal concentration from the base to the top within the tonstein layer indicates that the amount of fuel declined during the deposition probably due to the consumption of vegetation by the fire. The presence of inertinite in coals overlying and underlying the tonstein layer indicates that fire-events were not restricted to the ash fall interval. The integration of the new data presented in the current study with previously published data for the Faxinal Coalfield demonstrates that volcanic events that occurred in the surrounding areas can be identified as one potential source of ignition for the wildfires. The presence of charcoal in Permian sediments associated with coal levels at different localities demonstrates that wildfires have been relatively common events in the peat-forming environments in which the coal formation took place in the Paraná Basin.

Early Permian colonial rugose corals from the Stikine River area, British Columbia, Canada

1989 ◽  
Vol 63 (2) ◽  
pp. 158-181 ◽  
Author(s):  
Calvin H. Stevens ◽  
Barbara Rycerski
Keyword(s):  
British Columbia ◽  
New Species ◽  
Lower Permian ◽  
Early Permian ◽  
Klamath Mountains ◽  
Coral Fauna ◽  
Rugose Corals ◽  
Two New Species ◽  
Three New Species ◽  
One New Species

Twenty-two species of Early Permian colonial rugose corals belonging to 12 genera from 10 locations in the Stikine River area in northwestern British Columbia, Canada, are described. These include three new species ofFomichevella(F. magna, F. southeri, F. bamberi); two species ofHeintzella; five species ofHeritschioides, of which three are new (H. bagleyae, H. garvinae, H. hoganae); two new species ofParaheritschioides(P. jennyi, P. wickenae); one new species questionably assigned toKleopatrina(K.?stikinensis); two new species ofPetalaxis(P. guaspariniae, P. neriae); and two new species ofLytvophyllum(L.?mongeri, L. wersoni). In addition, five new species assigned to five new genera are here namedEastonastraea complexa, Fedorowskiella simplex, Pararachnastraea lewisi, Stikineastraea thomasi, andWilsonastraea rigbyi.These corals occur in rocks forming part of the Stikine terrane, the largest tectonostratigraphic unit in western Canada. This coral fauna shows a very close affinity with that of the Lower Permian McCloud Limestone of the eastern Klamath Mountains of northern California, and there is some similarity to the Coyote Butte fauna of central Oregon. Several species compare most closely with species from Spitsbergen, but there are few similarities with any cratonal North American faunas and none with Tethyan faunas.

scholarly journals Ecophenotypic variation and phylogeny within the Erisocrinacea (Crinoidea): linkage of morphology, ecology, & sea - level in the Late Paleozoic

1992 ◽  
Vol 6 ◽  
pp. 131-131
Author(s):  
Peter F. Holterhoff
Keyword(s):  
Body Size ◽  
Sea Level ◽  
Maximum Size ◽  
Intermediate Frequency ◽  
Characteristic Size ◽  
Second Order ◽  
Metabolic Energy ◽  
Lower Permian ◽  
Early Permian ◽  
Fifth Order

Cyclothems (fifth - order depositional sequences) are the fundamental stratigraphic motif of the Upper Pennsylvanian and Lower Permian of the North American mid - continent. Through this interval, sequences display an overall second order regression modulated by intermediate frequency sea-level fluctuations. Thus, shelfward incursions of offshore (basinal) facies are more extensive in the lower Upper Pennsylvanian, while merely shoaling facies characterize marine units of many higher sequences.Within basal Upper Pennsylvanian (Missourian) sequences, species of the Erisocrinacea are ubiquitous members of nearshore and offshore crinoid assemblages. However, the species Erisocrinus typus and Delocrinus subhemisphericus display significant ecophenotypic variation between facies: smaller mean and maximum size characterizes offshore/transgressive populations while larger size characterizes nearshore/regressive populations. It is proposed that these are hydrographically - controlled phenotypes: offshore, quiet bottom waters inhibit effective filtration, imposing a metabolic energy threshold beyond which larger morphologies are not viable while nearshore populations are able to assume larger body sizes.Shifting now to the Catacrinidae within the Erisocrinacea, as the frequency of interbasinal drowned shelf conditions waned through the Late Pennsylvanian, new species, inhabiting regressive facies, increased maximum body size and diversity for the family. Thus, lower Virgilian assemblages are highly variable in characteristic size, with smaller, ancestral D. subhemisphericus dominant in offshore facies while robust D. vulgatus, Pyndaxocrinus sp., and Arrectocrinus sp. dominate nearshore facies. Speciation may have involved the stabilization and subsequent diversification of the earlier nearshore phenotype.Through the remainder of the Virgilian and into the Early Permian, near the terminal late Early Permian regression, larger morphologies, represented by D. brownsvillensis, D. vastus, and A. abruptus, dominate midcontinent crinoid assemblages; smaller offshore species had been lost, thus increasing body size for the clade as a whole.Thus, it appears that the same parameters which controlled morphological expression at the fifth - order level (ecophenotypic variation) may also have acted at the second - order level (phylogenetic trend). The interrelationship between sub-cycle and super-cycle sea - level and metabolic viability is paramount to understanding potential morphologies for this clade. However, these factors may not have ultimately influenced clade diversity.

Aspects of the postcranial skeleton of the Lower Permian lungfish, Gnathorhiza

1989 ◽  
Vol 63 (6) ◽  
pp. 919-930 ◽  
Author(s):  
Walter W. Dalquest ◽  
M. John Kocurko ◽  
John V. Grimes
Keyword(s):  
Axial Skeleton ◽  
Lower Permian ◽  
Fish Scales ◽  
Early Permian ◽  
Postcranial Skeleton ◽  
Caudal Fin ◽  
North Central ◽  
New Information ◽  
Central Texas ◽  
Median Fins

A newly discovered locality of aestivation burrow casts containing the lungfish, Gnathorhiza serrata, is reported from the early Permian Arroyo Formation of Wilbarger County, north-central Texas. Remains preserved in the burrow casts provide sections of mummified Gnathorhiza and new information about the postcranial skeleton of this fish. Scales of Gnathorhiza resemble those of the modern lungfishes such as Lepidosiren in their microanatomy. No traces of paddle-like pectoral or pelvic fins were found and paired fins of Gnathorhiza may have resembled those of Lepidosiren. The axial skeleton and median fins of Gnathorhiza seem to resemble those of Lepidosiren except that the tail area and caudal fin of Gnathorhiza were stout and strong rather than slender and tapering. Gnathorhiza, which aestivated tail-down in its burrow, may have required a stout tail for support.

A giant Permian fusulinid from east-central Alaska with comparisons of all giant fusulinids in western North America

1995 ◽  
Vol 69 (5) ◽  
pp. 805-812 ◽  
Author(s):  
Calvin H. Stevens
Keyword(s):  
North America ◽  
Related Species ◽  
The Other ◽  
Lower Permian ◽  
Early Permian ◽  
Western North America ◽  
Closely Related Species ◽  
East Central ◽  
West Texas ◽  
Species Groups

The discovery of a new locality yielding giant Guadalupian (Lower Permian) fusulinids in east-central Alaska extends the range of these forms much farther north than previously known, and into a tectonostratigraphic terrane from which they previously had not been reported. The number of areas from which giant parafusulinids are known in North America is thus raised to eight. Three of these localities are in rocks that previously had been referred to the allochthonous McCloud belt arc, and one, West Texas, is known to have been part of Paleozoic North America. Comparison of species from all areas suggests that there are two closely related species groups: one represented in Texas and Coahuila, and the other represented in Sonora, northern California, northeastern Washington, southern and northern British Columbia, Alaska, and apparently in Texas. These groups may differ because they are of slightly different ages or because interchange between the faunas of Texas–Coahuila area and the other regions was somewhat inhibited during the Early Permian.

scholarly journals Supplemental Material: Crustal material recycling induced by subduction erosion and subduction-channel exhumation: A case study of central Tibet (western China) based on P-T-t paths of the eclogite-bearing Baqing metamorphic complex

2020 ◽  
Author(s):  
Xin Jin ◽  
Yu-Xiu Zhang ◽  
Kai-Jun Zhang ◽  
et al.
Keyword(s):  
Western China ◽  
Metamorphic Rocks ◽  
Crustal Material ◽  
Metamorphic Complex ◽  
Subduction Channel ◽  
Material Recycling ◽  
Subduction Erosion ◽  
Mineral Compositions ◽  
Central Tibet

Compositional mapping images of one garnet, Triassic paleo-geographic facies of Qiangtang, summarized published Paleozoic and Proterozoic ages in Tibetan Plateau and Himalaya, mineral compositions, and chronology data of the Baqing metamorphic rocks.

Subduction erosion and crustal material recycling indicated by adakites in central Tibet

Geology ◽  
2021 ◽  
Author(s):  
Zong-Yong Yang ◽  
Qiang Wang ◽  
Lu-Lu Hao ◽  
Derek A. Wyman ◽  
Lin Ma ◽  
...  
Keyword(s):  
Crustal Material ◽  
Convergent Margins ◽  
Nd Isotopes ◽  
Magmatic Arc ◽  
Material Recycling ◽  
Intrusive Rocks ◽  
Subducted Oceanic Crust ◽  
Subduction Erosion ◽  
Central Tibet ◽  
Qiangtang Terrane

Subduction erosion is important for crustal material recycling and is widespread in modern active convergent margins. However, such a process is rarely identified in fossil convergent systems, which casts doubt on the importance of subduction erosion through the geological record. We report on ca. 155 Ma Kangqiong (pluton) intrusive rocks of a Mesozoic magmatic arc in the southern Qiangtang terrane, central Tibet. These rocks mainly consist of trondhjemites and tonalites and are similar to slab-derived adakites with mantle-like zircon oxygen isotope compositions (δ18O = 5.2‰–5.6‰), they display more evolved Sr-Nd isotopes and higher Th/La relative to mid-oceanic ridge basalts from the Bangong-Nujiang suture, and they contain abundant amphibole and biotite. These characteristics indicate magma generation via H2O-fluxed melting of eroded forearc crust debris with subducted oceanic crust at 1.5–2.5 GPa and 700–800 °C. In addition, the intrusions are exposed <20 km north of the Bangong-Nujiang suture. Given the formation of adakites, narrow arc-suture distance, migration of the Jurassic frontal arc toward the continent interior, and other independent geological archives, we suggest that the hydrated forearc crust materials were removed from the overlying plate and carried into the mantle by subduction erosion. Our study provides the first direct magmatic evidence for a subduction erosion process in pre-Cenozoic convergent systems, which confirms an important role for such processes in subduction-zone material recycling.

scholarly journals First record of catacrinid crinoid from the Lower Permian of Spitsbergen

2013 ◽  
Vol 34 (2) ◽  
pp. 139-150 ◽  
Author(s):  
Przemysław Gorzelak ◽  
Błażej Błażejowski ◽  
Alfred Uchman ◽  
Nils−Martin Hanken
Keyword(s):  
First Record ◽  
Lower Permian ◽  
Early Permian ◽  
Considerable Part ◽  
Generic Level ◽  
Degree Of Certainty ◽  
First Time

AbstractAn early Permian (late Artinskian-Roadian) cladid crinoid (Catacrinidae gen. et sp. indet.) is reported for the first time from the Vøringen Member of the Kapp Starostin Formation of Spitsbergen. The specimen is partly articulated and preserves a considerable part of its stalk and a complete cup, but only the proximal portions of its arms. Thus, it can− not be identified with any degree of certainty at the generic level. Despite this, our finding is important as it constitutes one of the youngest records of catacrinid crinoids to date and con− siderably extends the palaeogeographic distribution of this group.

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