A Guadalupian-Lopingian (Middle to Late Permian) brachiopod fauna from the Juripu formation in the Yarlung-Zangbo suture zone, Southern Tibet, China

A brachiopod fauna of 16 species belonging to 11 genera and three genera and species indeterminate from the middle and upper parts of the Juripu Formation in the Yarlung-Zangbo (Indus-Tsangbo) Suture zone (=Yarlung-Zangbo River zone), southern Tibet, is described and figured for the first time. A new species, Taeniothaerus zhongbaensis, is described. The fauna is comparable with that in the Kalabagh Member of the Wargal Formation of the Salt Range, Pakistan, and is considered to be most likely Capitanian (late Guadalupian/Middle Permian) to Wuchiapingian (early Lopingian/early Late Permian) in age, as indicated by the majority of the brachiopod species and by being constrained by an underlying fusulinacean fauna (Parafusulina Zone) and an overlying ammonite fauna (Cyclolobus fauna).

Early carboniferous brachiopod faunas from the Baoshan block, west Yunnan, southwest China

38 brachiopod species in 27 genera and subgenera are described from the Yudong Formation in the Shidian-Baoshan area, west Yunnan, southwest China. New taxa include two new subgenera: Unispirifer (Septimispirifer) and Brachythyrina (Longathyrina), and seven new species: Eomarginifera yunnanensis, Marginatia cylindrica, Unispirifer (Unispirifer) xiangshanensis, Unispirifer (Septimispirifer) wafangjieensis, Brachythyrina (Brachythyrina) transversa, Brachythyrina (Longathyrina) baoshanensis, and Girtyella wafangjieensis. Based on the described material and constraints from associated coral and conodont faunas, the age of the brachiopod fauna from the Yudon Formation is considered late Tournaisian (Early Carboniferous), with a possibility extending into earlyViseacutean.

Permian of West Yunnan, Southwest China: a biostratigraphic synthesis

Recent progress in the study of Permian stratigraphy of western Yunnan, southwest China, is reviewed with particular references to the Tengchong and Baoshan blocks and the Changning–Menglian Belt. Where confusion or controversy exists in stratigraphical nomenclature and/or dating, we attempt to clarify the situation based on our recent field observations and newly obtained research results. The Permian within the Changning–Menglian Belt embraces different stratigraphic successions, suggesting different tectonic settings, ranging from passive margin and active margin, to oceanic basin and seamounts. Permo-Carboniferous faunas in the carbonate sequences of the Changning–Menglian Belt are of typical Cathaysian affinity, as demonstrated by abundant fusulinaceans and compound rugose corals. The Permian stratigraphy and faunas of the Tenchong and Baoshan blocks are markedly different from those of the Changning–Menglian Belt. The Baoshan Block lacks Upper Carboniferous deposits, and its subsequent Lower Permian sequence consists predominantly of siliciclastic strata yielding cool-water faunas and possibly glaciogene diamictites, overlain by thick basaltic lava and volcaniclastics of probably rift origin. The upper part of the Permian in the Baoshan Block is characterized by carbonates containing mixed Cathaysian and Gondwanan faunas. The Tengchong Block has a similar evolutionary history to the Baoshan Block, but completely lacks volcanic rocks.

A Wuchiapingian (Late Permian) brachiopod fauna from an exotic block in the Indus–Tsangpo suture zone, southern Tibet, and its palaeobiogeographical and tectonic implications

A brachiopod fauna including 19 species of 17 genera from an exotic block in the Indus–Tsangpo suture zone in southern Tibet is described and illustrated. The brachiopod fauna is dominated by Martinia elegans and two new taxa: Jinomarginifera lhazeensis gen. et sp. nov. and Zhejiangospirifer giganteus sp. nov. The fauna is closely comparable with those from the middle and upper parts of the Wargal Formation and the Chhidru Formation in the Salt Range of Pakistan, the Chitichun Limestone in southern Tibet, and the Basleo area of West Timor, and these correlations suggest a Wuchiapingian age. The fauna exhibits substantial links with both peri–Gondwanan and Cathaysian faunas, which may imply that it is a seamount biota originally located in the southern margin of the Neotethys during the Late Permian, and was later (in the early Cenozoic) displaced and became sandwiched into younger marine deposits in the collision process between India and Eurasia.

The Carboniferous and Permian sequences in north and south of the Longmucuo-Shuanghu suture zone in Tibet

The location of the Palaeo-tethys suture in Tibet has been in great dispute for past two decades. The Longmucuo-Shuanghu suture has long been considered as the Palaeo-tethys in Tibet. Restudy of the Carboniferous and Permian sequences in the north and south of this suture reveal that: (1) the Carboniferous and Permian sequence of the North Qiangtang Block is characterized by containing compound corals and intact fusulinids zones from Moscovian Fusulinella, Fusulina to Changhsingian Palaeofusulina zones; (2) the Early Permian of the South Qiangtang Block is

Taphonomy and palaeobiology of early Middle Triassic coprolites from the Luoping biota, southwest China: implications for reconstruction of fossil food webs

Abundant, exceptionally preserved coprolites are documented from the Luoping biota (Anisian, Middle Triassic) of Yunnan Province, southwest China. These coprolites can be categorized into fourmorphological types: A) bead to ribbon-shaped, B) short to long cylindrical-shaped, C) flattened, disk-like, and D) segmented faeces. Detailed multi-disciplinary studies reveal that coprolite type A was likely produced by invertebrate animals,while coprolite types B to D could be faeces generated by carnivorous fishes or marine reptiles, perhaps from different taxonomicgroups. When compared with coprolites reported from the Lower Triassic, the Luoping forms indicate more complicated predation-prey food web networks. These evidences, combined with body fossil discoveries fromLuoping, suggest the emergence of complex trophic ecosystems in the Anisian,marking the full biotic recovery following the Permian–Triassic Mass Extinction.

Late Middle Permian (Guadalupian) fusuline fauna from the Gyanyima area of Burang County, Tibet, China and its paleobiogeographic implications

Numerous Permian limestone blocks exposed along the Yarlung-Zangbo Suture Zone have been named Tibetan facies exotic limestone blocks or Chitichun-type Permian deposits.The Gyanyima limestone block,one of those limestone blocks,is located in Burang County,southwestern Tibet.Fusulines are abundant in the Gyanyima limestone block especially for Middle Permian Xilanta Formation.The fusuline fauna comprises 10 genera,respectively Neoschwagerina, Yangchienia, Armenina, Verbeekina, Paraverbeekina, Kahlerina, Lantschichites, Codonofusiella,Chusenella, Nankinella.This fauna indicates a Midian age(Late Guadalupian or Lengwuan age of South China) in terms of the coexistence of Kahlerina, Lantschichites, Codonofusiella and Neoschwagerina.

High-resolution terrestrial permian-triassic eventostratigraphic boundary in western Guizhou and eastern Yunnan, southwestern China

The adjoining area of western Guizhou and eastern Yunnan Provinces in southwest China is an ideal place to investigate the feasibility of correlating marine and nonmarine Permian–Triassic boundary (PTB) sequences, as it contains outcrop sections of shallow marine, marginal marine (or paralic), and terrestrial PTB sections, all in close geographic proximity. This paper documents for the first time multiple stratigraphic data from several well-preserved terrestrial PTB sections in the area and attempts to use these data to define, locate, and correlate the PTB in the area. A study of the spores and pollen and vegetation types across the terrestrial PTB sections in the study area suggests three distinct evolutionary stages across the boundary: Stage 1 (Xuanwei Formation) is characterised by Late Permian or Paleozoic-type ferns and pteridosperms (85.0%), with a few gymnosperms (15.0%); stage 2 is marked by an abrupt drop of sporopollen elements of Late Permian aspects, coupled with the appearance of fungal spores and limited Early Triassic palynomorphs; stage 3 (top Xuanwei Formation and Kayitou Formation) is dominated by gymnosperm pollen (58.8%) of clearly Early Triassic aspect, although still retaining limited ferns and pteridosperms. The three biotic stages seem to well correspond with the changing trend of the δ13Corg curves from the same sections, which is characterized by a sharp drop just before the PTB, followed by a short term partial recovery across the boundary, and then succeeded by a gradual decline after the PTB in the Early Triassic. Combining evidence from eventostratigraphic (i.e., the succession of boundary clay beds), biostratigraphic (using both macroplants and palynomorphs), and chemostratigraphic (i.e., organic carbon isotope excursion signals), we propose that a high-resolution PTB succession, closely correlatable to its marine counterpart at the Meishan section in eastern China, is recognisable at the terrestrial PTB sections in the western Guizhou–eastern Yunnan area in southwest China.

Permian brachiopods from the Baoshan and Simao Blocks in Western Yunnan, China

This paper describes and illustrates four Permian brachiopod assemblages (Assemblages A–D) from western Yunnan, southwest China. Assemblage A occurs in the basal part of the Yongde Formation in the Xiaoxinzhai section in the southern Baoshan Block and is assignable to the latest Artinskian or earliest Kungurian. Assemblage B occurs about 50 m stratigraphically above Assemblage A in the same section, and is of Chihsian (Kungurian–Roadian) age. Assemblage C was collected from the Yongde Formation in the Anpaitian section in the southern Baoshan Block and is most likely Roadian to Wordian in age. Assemblage D came from the Longtan Formation in the Simao Block and is of late Wuchiapingian in age. The brachiopod faunas from the Yongde Formation of the Baoshan Block, as a whole, is dominated by species characteristic of the Cathaysian Province, although some links with Peri-Gondwanan faunas are also evident. In contrast, Assemblage D from the Simao Block is characterised exclusively by taxa of the Cathaysian Province. New taxa described and illustrated are Neochonetes (Huangichonetes) inflatus n. sp. Costatumulus minor n. sp. and Celebetus yunnanensis n. sp.

Life crises on land across the Permian–Triassic boundary in South China

The western Guizhou and eastern Yunnan area of southwest China commands a unique and significant position globally in the study of Permian–Triassic boundary (PTB) events as it contains well and continuously exposed PTB sections of marine, non-marine and marginal-marine origin in the same area. By using a range of high-resolution stratigraphic methods including biostratigraphy, eventostratigraphy, chronostratigraphy and chemostratigraphy, not only are the non-marine PTB sections correlated with their marine counterparts in the study area with high-resolution, the non-marine PTB sections of the study area can also be aligned with the PTB Global Stratotype Section and Point (GSSP) at Meishan in eastern China. Plant megafossils (“megaplants”) in the study area indicate a major loss in abundance and diversity across the PTB, and no coal beds and/or seams have been found in the non-marine Lower Triassic although they are very common in the non-marine Upper Permian. The megaplants, however, did not disappear consistently across the whole area, with some elements of the Late Permian Cathaysian Gigantopteris flora surviving the PTB mass extinction and locally even extending up to the Lower Triassic. Palynomorphs exhibit a similar temporal pattern characterized by a protracted stepwise decrease from fern-dominated spores in the Late Permian to pteridosperm and gymnosperm-dominated pollen in the Early Triassic, which was however punctuated by an accelerated loss in both abundance and diversity across the PTB. Contemporaneous with the PTB crisis in the study area was the peculiar prevalence and dominance of some fungi and/or algae species.

The temporal patterns of megaplants and palynomorphs across the PTB in the study area are consistent with the regional trends of plant changes in South China, which also show a long-term decrease in species diversity from the Late Permian Wuchiapingian through the Changhsingian to the earliest Triassic, with about 48% and 77% losses of species occurring respectively in the end-Wuchiapingian and end-Changhsingian. Such consistent patterns, at both local and regional scales, contradict the hypothesis of a regional isochronous extinction of vegetation across the PTB, and hence call into question the notion that the end-Permian mass extinction was a one-hit disaster. Instead, the data from the study area and South China appears more consistent with a scenario that invokes climate change as the main driver for the observed land vegetation changes across the PTB in South China.

A biogeographically mixed late Guadalupian (late Middle Permian) brachiopod fauna from an exotic limestone block at Xiukang in Lhaze county, Tibet

A total of 17 brachiopod species belonging to 15 genera are recorded from a limestone block of about 3×4 km2 in the Indus–Tsangbo suture zone at Xiukang in Lhaze County of Tibet. The brachiopod fauna generally indicates a Late Guadalupian age (late Wordian–Capitanian, late Middle Permian) based on its association with the Timorites-bearing ammonoid fauna and the presence of the brachiopod Urushtenoidea crenulata. Palaeobiogeographically, the fauna exhibits transitional/mixed characters between the warm-water Cathaysian and cold to temperate Gondwanan faunas and may have developed on a carbonate build-up or seamount on the oceanic crust.

Lopingian (Late Permian) stratigraphy, sedimentation and palaeobiogeography in southern Tibet

Investigations of the Permian-Triassic sections and limestone blocks scattered in the Indus-Tsangbo Suture Zone in southern Tibet show widespread distribution of the Lopingian strata. The Lopingian deposits mostly contain rich brachiopod fossils and characteristic conodonts of the Mesogondolella shenz Zone of latest Changhsingian age in the topmost part. Brachiopod assemblages are largely comparable with those known from the upper Wargal and Chhidru Formations of the Salt Range, Pakistan, the Zewan Formation of Kashmir, the upper part of the Kuling Group in Spiti of India and the Hardman Formation of Western Australia. A revised Lopingian (Late Permian) age is proposed for the Selong Group and its equivalents in southern Tibet. The Lopingian deposits in southern Tibet can be grouped into three different sedimentary types, each of which reflects different sedimentary environments from coastal to continental shelfal settings on the northern peri-Gondwanan margin. The Qubu-type sequence represents marine coastal and proximal barrier-lagoon sediments during a gradual sea-level rise. Micaceous sandstone and shale of regressive origin, with abundant palynomorphs and acritarches, developed during the Late Lopingian sea-level lowstand, which is followed by a major rapid transgression at the very end of Permian. The Selong-type sequence in the Selong area consists of bioclastic limestone and calcareous shale in the lower part, and crinoid grainstone in the upper part. The latter part is believed to have been formed in a high-energy inner shelf shoal setting. The Chitichun-type sequence, sporadically distributed along the Indus-Tsangbo suture zone as small limestone blocks, consists of pure bioclastic sparite with the ammonoid Cyclolobus fauna. It is interpreted as the break-up products of sea-mounts and/or small isolated carbonate build-ups developed on the outer shelfal settings.

A biogeographically mixed, Middle Permian brachiopod fauna from the Baoshan Block, Western Yunnan, China

A small brachiopod fauna is described from the carbonate rocks of the basal Shazipo Formation of the Baoshan Block, western Yunnan, south-west China, including significant new ventral and dorsal internal morphological features of Cryptospirifer omeishanensis Huang. This fauna is regarded as Wordian (Middle Guadalupian, Middle Permian) because of the presence of Cryptospirifer omeishanensis Huang and associated fusulinids (Neoschwagerina craticulifera Zone). Palaeobiogeographically, the brachiopod fauna is of considerable interest because of its admixed nature characterized by typical warm-water Cathaysian elements intermingled with temperate Peri-Gondwanan taxa. This in turn is interpreted to indicate that the Baoshan Block may have been situated in an intermediate palaeogeographical position between Gondwanaland to the south and Cathaysia to the north during the Mid Permian and, as such, it probably furnished an important 'stepping stone' for the dispersal of Mid Permian eastern Tethyan marine invertebrate taxa (e.g. Cryptospirifer) to the western Tethys.