Changhsingian (Late Permian) foraminifers from the topmost part of the Xiala Formation in the Tsochen area,central Lhasa Block,Tibet and their geological implications

A foraminiferal fauna consisting of 15 genera and 19 species is documented for the first time from the topmost part of the Xiala Formation in the Aduogabu area in Tsochen County, central Lhasa Block. This foraminiferal fauna is dominated by Colaniella, indicating a broadly Changhsingian age. The presence of Colaniella, Reichelina and absence of the typical tropical fusuline genus Palaeofusulina in the fauna indicate that the Lhasa Block has not merged into equatorial regions during the Changhsingian. More importantly, the widespread Lopingian (Late Permian) marine carbonates with warm-water faunas and the stable platform carbonate sequence through the Guadalupian and Lopingian in the Lhasa Block present an obvious contrast against the contemporaneous sequences in the South Qiangtang Block and Gondwana margin. It suggests that both the Bangong-Nujiang Ocean and the Neotethys Ocean would have opened by the Guadalupian and Lopingian.     

An upper Kungurian/lower Guadalupian (Permian) brachiopod fauna from the South Qiangtang Block in Tibet and its palaeobiogeographical implications

A brachiopod fauna including 15 species belonging to 14 genera is described from a thin carbonate succession of the Lugu Formation at the Anmu section in the northern part of the South Qiangtang Block, which is about 15 km south to the Longmu Co-Shuanghu Suture. The brachiopod fauna is late Kungurian or early Guadalupian in age in terms of the presence of the brachiopod species Vediproductus punctatiformis, “Cryptospirifer” omeishanensis, and Paraplicatifera regularis. This is also generally consistent with the age indicated by the fusulines (e.g., Cancellina, Chusenella, Monodiexodina, Nankinella, Neofusulinella, Pseudofusulina, and Sphaerulina) from this formation at the nearby Mari and Duoma A (DMA) sections. Palaeobiogeographically, the brachiopod fauna exhibits a typical Cathaysian affinity and all the species are reported commonly from the equivalents in South China and Cimmerian blocks, which strongly suggest that the South Qiangtang Block had drifted to a position in the warm-water or temperate regime close to South China.     

Multidisciplinary study of the Mechetlino Quarry section (Southern Urals,Russia) — The GSSP candidate for the base of the Kungurian Stage (Lower Permian)

The Mechetlino Quarry section is a potential candidate for the Global Section Stratotype and Point (GSSP) for the base of the Global Kungurian Stage on the International Stratigraphic Chart. In 2017, the Mechetlino Quarry section became the part of the First Geopark in Russia, therefore excavation work was carried out to clear it, a road was laid, and infrastructure was developed. Recent evidence to justify the base Kungurian boundary in the Mechetlino section was obtained. Additional conodonts confirmed the data of V.V. Chernykh on the Artinskian–Kungurian transition. Besides Neostreptognathodus pnevi Kozur and Movshovitsch, the second marker (N. lectulus Chernykh) of the base-Kungurian was established. The Artinskian–Kungurian transition of the Mechetlino Quarry section is characterized by the richest associations of small foraminifers, ammonoids, and other groups. The occurrence of mass Clausiuraloceras above the Kungurian boundary, which changed the representative Artinskian association, was identified. Small foraminifers of the Artinskian–Kungurian transition are numerous and include sufficient species to provide a correlation with Western Tethys, Svalbard and Australia. Data on isotopic ratios of δ¹³C and δ¹⁸O, δ¹³C_org values and the magnetic susceptibility were obtained for the first time.     

The Permian fusulinoidean faunas of the Sibumasu and Baoshan blocks: their implications for the paleogeographic and paleoclimatologic reconstruction of the Cimmerian Continent

Permian fusulinoidean faunas occur in mainly four stratigraphic levels in the Baoshan Block of West Yunnan and the Sibumasu Block of Southeast Asia, which constituted part of the eastern Cimmerian Continent. The oldest fauna, from the upper part of the Dingjiazhai Formation in the Baoshan Block, consists of Pseudofusulina, Eoparafusulina, and a new boultoniid genus, and is assignable to the Yakhtashian (=Artinskian). The second one, which occurs in the basal part of the Ratburi Limestone and its equivalent strata in the Sibumasu Block, is represented by Monodiexodina, and is probably referable to the Bolorian (=Kungurian). The third fauna, composed of Eopolydiexodina, Rugososchwagerina, Yangchienia, Chusenella, Jinzhangia, and several other genera, is dated to the Murgabian (=Wordian), and occurs in the lower part of the Shazipo and Daaozi formations in the Baoshan Block and the main part of the Ratburi Limestone in the Sibumasu Block. The youngest fauna of probably Dzhulfian (=Wuchiapingian) age is found in the upper part of the Ratburi Limestone, and contains Nanlingella, Reichelina, Codonofusiella?, and a few staffellid genera. A smaller foraminiferal genus, Shanita, found from the upper part of the Ratburi Limestone and the upper part of the Shazipo Formation is also an important element of the foraminiferal assemblage near the Midian-Dzhulfian (=Capitanian-Wuchiapingian) boundary in the Baoshan and Sibumasu blocks.In the eastern Cimmerian Continent, low generic diversity throughout the Permian and the paucity of Tethys-characterizing neoschwagerinid and verbeekinid genera during Middle Permian time are two remarkable features of the Permian fusulinoidean faunas. In the Cimmerian Continent, the generic diversity of Permian fusulinoidean faunas in space and time gradually increases from the Early Permian to late Middle Permian as well as from the eastern Cimmerian areas to western ones. The temporal increase of the generic diversity can be explained by the northward drift of the Cimmerian Continent during Permian time. In contrast, the lower generic diversity of the eastern Cimmerian Permian fusulinoidean faunas against western ones is possibly due to an oblique arrangement of the continent to paleolatitude. Thus, the western Cimmerian Continent was more proximal to the tropical Tethyan domain than its eastern part. In addition, the Middle Permian Cimmerian paleobiogeographic region is likely to be subdivided into two subregions, the western Tethyan Cimmerian and the eastern Gondwanan Cimmerian, based on the distribution pattern of verbeekinid and neoschwagerinid fusulinoideans and overall generic diversity. The scarce occurrence or total absence of these essentially Tethys-indicating fusulinoideans in the Baoshan and Sibumasu blocks suggests that the eastern Cimmerian Continent was still far from the equatoro-tropical Cathaysian domain and was probably in a warm temperate or subtropical zone until the end of the Permian. The eastern Cimmerian areas finally migrated into a tropical zone by the Late Triassic judging from well-developed Carnian sponge-coral buildups in the Chaiburi Formation in the Sibumasu Block.     

老挝北部宾夕法尼亚纪的一个新(筳)类动物群

作者报道了一个小型■类动物群,包括Eostaffella? sp., Pseudoendothyra sp., Staffella pseudosphae-roidea Dutkevich, Neostaffella ( N.)sp ., Profusulinella bona Grozdilova et Lebedeva以及P.cf .prisca (Depart) ,此动物群是在老挝北部琅勃拉邦省西南部的Thong Phiang Vilay村附近的石灰岩山中发现的。根据Profusulinella bona和P.cf. prisca的出现,该动物群的时代可归到晚石炭世宾夕法尼亚纪巴什基尔期或莫斯科期最早期。这是在老挝北部对该时代■类动物群的首次报道。当前■类动物群证明琅勃拉邦地区和泰国北部的黎地区在地质上有重要的关系,表明老挝北部地区从地质构造上属于印度支那板块的边缘。     

西藏拉萨地块中部扎布耶茶卡一带中二叠世(蜓)类动物群及其古生物地理意义

对拉萨地块中部扎布耶茶卡北岸的两个剖面开展(虫筳)类动物群系统古生物学及古生物地理研究。鉴定出(虫筳)类 6 属 16 种,包括Yangchienia tobleri Thompson,Yangchienia haydeni Thompson,Chusenella brevipola (Chen),C. schwagerinaeformis Sheng,C. cf. brevis (Chen),C. sp.,Nankinella rarivoluta Wang,Sheng and Zhang,N. complanata Wang,Sheng and Zhang,Kahlerina tenuitheca Wang,Sheng and Zhang,K. pachytheca Kochansky-Devidé and Ramovs,Verbeekina americana Thompson, Wheeler and Danner,V. tenuispira Sheng,Neoschwagerina cheni Sheng,N. colaniae Ozawa,N. craticulifera (Schwager),N. brevis Thompson,Wheeler and Danner。基于Kahlerina属的出现及Neoschwagerina属的厚壁壳体以及第二旋向副隔壁发育较弱的形态特征,判断其时代为二叠纪瓜德鲁普世(Guadalupian)沃德期(Wordian)。该(虫筳)类动物群面貌可与拉萨地块的狮泉河地区、措勤夏东地区、申扎地区、林周地区等对比。拉萨地块从中二叠世开始普遍出现暖水(虫筳)类动物群,这与印度板块北缘特提斯喜马拉雅地区中、晚二叠世时期均以冷水的腕足生物群为主所反映的水体性质有明显的差异。这表明拉萨地块和喜马拉雅地区在晚三叠世之前仍然连在一起的可能性并不大,拉萨地块可能在瓜德鲁普世沃德期以前已经脱离冈瓦纳大陆。     

Main biotic and climatic events in Early Permian of the Western Urals,Russia, as exemplified by the shallow-water biota of the early Kungurian lagoons

The paper deals with the Early Permian (mostly early Kungurian) biotas of the Cis-Urals (Perm region, Russia). Taxonomic composition of the early Kungurian biota of the stratotype area (close vicinity of the City of Kungur) includes algae Algites philippoviensis Naugolnykh, A. shurtanensis Naugolnykh, tracheophytes (higher plants), i.e., equisetophytes Paracalamites spp., conifers Shaidurodendron columnaris Naugolnykh, Walchia appressa Zalessky, vojnovskyaleans Rufloria derzavinii (Neuburg) S. Meyen etc.; invertebrates: coelenterates of uncertain affinity, bivalves Permophorus costatus (Brown), Permophorus sp., Netschajewia sp. cf. N. tschernyshowi (Licharew), gastropods Goniasma angulata (Stuckenberg), terebratulid brachiopods Dielasma sp. cf. D. moelleri Tschernyschew, arthropods (limulids Paleolimulus kunguricus Naugolnykh); vertebrates: chondrichthyan and actinistian fishes.Paleogeographically, the studied area belonged to the near-shore zone of a large lagoon basin disposed along the western-southern part of the Paleo-Urals during the Kungurian time. The main events in evolution of this basin reflect the final phases of the Artinskian sea basin with normal salinity, the transition to an early Kungurian (Philippovian) lagoon, then the appearance of intercalations of evaporate conditions and episodic incursion of marine faunas, and finally a gradual transition to semi-terrestrial environments with the cyanophyte communities in early Ufimian (Solikamskian, early Roadian) time. Climatic conditions in this area changed from semi-humid to semi-arid. A new genus and species of algae Dichothallus divaricatus Naugolnykh n. gen. n. sp. is described on the basis of material originated from the stratotype of the Philippovian Horizon of the Kungurian stage, Lower Permian.     

Biostratigraphy and palaeobiogeography of Lower Permian (lower Kungurian) conodonts from the Tak Fa Formation (Saraburi Limestone), Thailand

Lower Permian (lower Kungurian) conodonts are reported from the Indochina Block of Southeast Asia. The fauna from the Tak Fa Formation of the Saraburi Limestone Group exposed in limestone hills NNW of Khok Samrong, Thailand, includes Sweetognathus subsymmetricus Wang, Ritter and Clark (early forms) and Pseudosweetognathus costatus Wang, Ritter and Clark. The co-occurrence of these species indicates a Lower Permian age (upper half of the lower Kungurian) for the sampled limestones representative of the Mesogondolella siciliensis–S. subsymmetricus Zone of South China. Sweetognathus and Pseudosweetognathus are for the first time reported from the Indochina terrane located in the palaeoequatorial belt in the Kungurian. Pseudosweetognathus appears restricted to the Kungurian of the South China and Indochina terranes thus supporting palaeogeographic reconstructions that isolate these terranes within the Palaeo-Tethys during the Kungurian.     

Conodonts from the Permian Jisu Honguer (Zhesi) Formation of Inner Mongolia, China

The Jisu Honguer Formation (“Zhesi Formation”) is a North China marine carbonate unit of Permian age containing a mixed fauna of Tethyan, Boreal and endemic elements. The age of the Jisu Honguer Formation has been thought to range from Artinskian to Kazanian based on previous studies using mostly benthic macrofossils. A typical Mesogondolella aserrata conodont fauna is reported from the lower part of the upper member of the Jisu Honguer Formation in the Ulanqub District, Zhesi area, of northern China. The fauna indicates a Middle Permian (Guadalupian) age, most likely late Wordian to early Capitanian, for the strata yielding conodonts. The whole Jisu Honguer Formation could be assigned to the Wordian to early Capitanian age. The overlying Yihewusu Formation is probably of Capitanian age. There are no Wuchiapingian marine deposits in the Zhesi area. As characteristic of the open sea Guadalupian conodont faunas of the Tethys, smooth Mesogondolella dominate the fauna. The view that all Tethyan Guadalupian conodont faunas consist exclusively of serrated Mesogondolella cannot be confirmed. Three new species are described: Mesogondolella neoprolongata C. - y. Wang, Mesogondolella mandulaensis C. - y. Wang and Wardlawella jisuensis C. - y. Wang.     

Artinskian–Wordian antitropical rugose coral associations: A palaeogeographical approach

Recent investigations in the Urals and East-European Platform as well as study of corals collections from South Primorye (Russian Far East) and South-Eastern Pamirs have been undertaken. Antitropical rugose associations include taxa that are bounded in their distribution by the temperate zones of the Boreal and Perigondwanan realms. They occur sporadically in tropical latitudes but never form abundant and diverse communities. Antitropical associations are represented by the so-called ‘Cyathaxonia fauna’ (sensu lato), predominating in two selected stratigraphic intervals. The abrupt change of taxonomic composition from colonial to ‘Cyathaxonia fauna’ allows the separation of two assemblages: (i) mid Artinskian–Kungurian and (ii) Roadian–Wordian. The key regions for comparison are the Urals (mid Artinskian–Kungurian), Spitsbergen (Kungurian–Wordian), East-European Platform (Roadian), Texas (mid Artinskian–Kungurian), South Primorye (Wordian–Capitanian), South-Eastern Pamirs (Upper Artinskian), and the Sverdrup Basin (Wordian). The Late Artinskian fauna of the South-Eastern Pamirs and Wordian faunas of South Primorye bear features of mixed assemblages. A few models of the origination of antitropical assemblages are acceptable: (i) the convergent parallel evolution of Lophophyllidium in the Northern Hemisphere and Southern Hemisphere, (ii) a similar evolution trend developed in parallel in three geographically distant regions: Verbeekiella, Pseudowannerophyllum, and “Pseudoverbeekiella”, and (iii) immigration of some species within temperate zones caused by current circulation changes both in the Northern and Southern Hemispheres, as well as northward spreading of terranes in the Perigondwanan Realm.     

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.     

Lower Permian Bryozoa of the Jamal Formation from Bagh-e Vang (Shotori Mountains,northeast Iran)

Lower Permian Bryozoan fauna of Jamal Formation, exposed in Bagh-e Vang (Shotori Mountains, northeast Iran) includes six species. Three species – Streblotrypa (Streblascopora) marmionensis (Etheridge 1926), Rhabdomeson bispinosum (Crockford 1944) and Alternifenestella kungurensis (Stuckenberg 1898) – indicate the Lower Permian (Artinskian to Kungurian) age of the formation. Three additional taxa – Fistulipora sp. 1, Fistulipora sp. 2 and undetermined timanodictyid bryozoan ?Timanodictya sp. could not be identified at the species level. The investigated fauna refers to Uralian and Australian palaeobiogeographic provinces.     

A new genus of male cones of voltzialean affinity,Uralostrobus voltzioides nov. gen., nov. sp., from the Lower Permian of the Urals (Russia)

A new genus and species of male cones of coniferophyte from the Lower Permian (Artinskian and Kungurian) deposits of the Urals, Russia is described: Uralostrobus voltzioides Naugolnykh nov. gen., nov. sp. The cone shows characters typical of some representatives of conifers belonging to the order Voltziales: more or less isometrical bracts of rhombic shape, prolonged sporangia with attenuate apices, and bisaccate pollen of Illinites-type. General information on the associated female seed scales and vegetative leafy shoots is given as well.     

Brachiopods from the Cisuralian–Guadalupian of Darvaz,Tajikistan and implications for Permian stratigraphic correlations

In this paper, we describe the upper Cisuralian Safetdara and Gundara formations of the Darvaz mountains, North Pamir, which were part of the Kunlun Arc, developed along the active Eurasian margin. The Safetdara Formation comprises massive limestones (mainly cyanobacterial, Tubiphytes and Archaeolithoporella boundstones) alternating with well-bedded bioclastic and oncoidal limestones and an interval of recessive shales. The formation crops out above the Chelamchi Formation consisting of turbiditic siltstones and sandstones with bioclastic silty limestones yielding massive limestone olistoliths. The Gundara Formation consists of fine sandstones at the base, followed by well-bedded marly bioclastic, oncoidal and microbial limestones, bearing a rich silicified brachiopod fauna in life-position. Two new taxa have been identified in this association: the cemented coralliform Gundaria insolita n. gen. n. sp. and the pedicle attached Hemileurus politus n. sp. The inferred environmental setting is that of shoal deposits of warm, shallow, high energy, clear marine waters for the Safetdara Formation. The agglutinated microbial reefs to cluster reefs of the Gundara Formation were probably growing in a muddier, quieter and probably slightly deeper setting.The foraminifers of the Brevaxina Zone suggest a Bolorian age for the top of the Chelamchi Formation, the Safetdara Formation and the base of the Gundara Formation. Kungurian conodonts have been found in the lower part of the Safetdara Formation. The biostratigraphic data from the sedimentary succession of North Pamir, integrated with those already obtained from Southeast Pamir, allow to refine the correlations between the Tethyan regional scale and the International Time Scale. In particular, it seems now clear that the Bolorian and the lower part of the Kubergandian correlate to the Kungurian.     

Crustaceen-Koprolithen aus der Trias der westlichen Tethys (Lienzer Dolomiten, Österreich; Pragser Dolomiten,Italien) und vom Gondwana-Westrand (oberes Magdalenatal,Kolumbien, Südamerika)

We describe Triassic Crustacean microcoprolites from the western Tethyan realm (Lienz Dolomites, Southern Alps) and from the western shores of Gondwana (upper Magdalena valley, Colombia, South America). The Colombian fauna originates from the Norian Payandé Formation and represents the first discovery of microfossils in this formation. The Colombian fauna is highly diverse and shows close affinities to faunas of the western Tethyan and Mediterranean region but also to North American faunas. The form speciesPalaxius colombiensis andPalaxius groesseri are new, and forPalaxitts shastaensis the genusPayandea n. gen. is erected.Thoronetia quinaria is revised. It is shown, that crustacean microcoprolites are a good tool for supra-regional stratigraphic correlation. Possible migration paths are discussed.     

滇西保山地区丁家寨组、卧牛寺组牙形刺的时代

本首次描述了滇西保山卧牛寺组及永德丁家寨组的Rabeignathus牙形刺动物群,其中2个新种：Rabeignathus yunnanensis sp．nov．,R．ritterianus sp．nov．,并划分出3个牙形刺带,进一步确定了古生物地层工作争论已久的卧牛寺组的时代为Artinskian晚期-Kungurian早期;丁家寨组上段为Sakmarian晚期-Artinskian早期。该牙形刺动物群为暖温型动物群,结合保山地块当时的古地磁资料,丁家寨组、卧牛寺组沉积之时,应处于边缘冈瓦纳区。卧牛寺组玄武岩喷发时间的确定,预示了保山地块从边缘冈瓦纳区分离出来的时间为Artinskian晚期。     

豫淮盆地太原组顶部斯威特刺(Sweetognathus)种的分类修正及其地层意义

作者通过对豫淮盆地太原组顶部灰岩中牙形刺的研究,发现Sweetognathus动物群较为丰富,计4属10种,含一个新种:Sweetognathuspraeiranicussp.nov.。其中以Sweetognathus最为繁盛,并对其种的分类进行了修正,将原定的Sweetognathusinornatus的大部分标本归入Sweetognathusmerrilli。根据新的分类,建立了两个组合带,即Sweetognathusmerrilli带和Sweetognathuswhitei-Xuzhougnathusmonoridgosus带。通过与国内外相当牙形刺组合带(带)的对比,初步认为该动物群属中、晚萨克马尔到早亚丁斯克期。     

Biostratigraphy and important biotic events in the Western Verkhoyansk Region around the Sakmarian–Artinskian boundary

A diverse marine invertebrate fauna was found in the Echij Formation (Sakmarian–Artinskian) at the Arkachan, Chelge, and Nizhnyaya Dielendzha sections, all Western Verkhoyansk Region, North-East of Russia. The biostratigraphic sequence of ammonoid, brachiopod, bivalve, and foraminiferal assemblages in the Echij Formation of the Western Verkhoyansk Region is studied. Five ammonoids units are identified in the Echian Regional Stage (“Horizon”): Uraloceras subsimense, Uraloceras omolonense, Neoshumardites triceps hyperboreus, Eotumaroceras endybalense, and Eotumaroceras subyakutorum beds. The first two divisions contain ammonoids of the Arkachanian association, and the last three contain the Endybalian association. The boundary between the Sakmarian and Artinskian stages is established at the base of Neoshumardites triceps hyperboreus beds. In the Sakmarian interval of the Echij Regional Stage of the Verkhoyansk Region, a brachiopod biostratigraphic sequence similar to that of the Kolyma–Omolon Region is observed: Jakutoproductus insignis, Jakutoproductus terechovi, and Jakutoproductus rugosus zones. In the lower part of the Artinskian stage, Uraloproductus stuckenbergianus beds are identified, which are characterized by a rich brachiopod assemblage (Peregoedov et al., 2009), not typical for Verkhoyansk Region. The bivalves, identified in the Lower Echij Subformation, presumably belong to the Merismopteria permiana, Cypricardinia eopermica, and Cypricardinia borealica zones of the Ogonerian Horizon of the Kolyma–Omolon Region. Bivalves of the Middle and Upper subformations are characteristic of the Edmondia gigantea and Aphanaia lima zones of the Koargychanian Regional Stage (“Horizon”). The foraminifera complex identified in the Echij Formation is compared with the complex of the lower part of the Sandy Foraminifera horizon of the northeast of the Siberian platform, to which the Tustakh Formation belongs. The beginning of the wide distribution of the Early Permian foraminifera in the Western Verkhoyansk Region was recorded at the base of the Artinskian. The Sakmarian–Artinskian boundary interval in the Verkhoyansk Region is characterized by three significant biotic events: the replacement of the brachiopod Jakutoproductus by Inoceramus-like bivalves, the first appearance of the Endybalian ammonoid association, and biotic invasions from the Uralian and North American regions. An important factor of the Late Sakmarian–Early Artinskian events was a large sea level rise (the Echian transgression), which significantly changed the environmental conditions for East Siberian marine invertebrates, and contributed to the spread of new faunas.     

滇西保山地区丁家寨组生物群的时代

首次系统描述保山地区丁家寨组的类化石,详细讨论丁家寨组所产类和腕足类动物群及孢粉植物群的时代和性质,提出丁家寨组的时代应与华南早二叠世的紫松阶相当,即相当于国际上的Ａｓｓｅｌｉａｎ阶至Ｓａｋｍａｒｉａｎ阶。确认丁家寨组不存在不同时代化石的再沉积混杂或大量化石时代倒置的异常现象。丁家寨组出现特提斯型Ｅｏｐａｒａｆｕｓｕｌｉｎａ动物类;腕足类组合属介于西澳区和泰马区之间的过渡动物群,西澳区的色彩较浓;     

Evolution of Permian conodont provincialism and its significance in global correlation and paleoclimate implication

The main components of Asselian through Artinskian conodont faunas found around the world are basically the same, and the provincialism is indicated only by less common endemic elements such as Gondolelloides and New Genus A Henderson in North Pangea, Sweetognathus bucaramangus around the equator and Vjalovognathus in eastern Gondwana. Provincialism is marked by differences at the species level of Mesogondolella, Neostreptognathodus and Sweetognathus during the Kungurian, and becomes very distinct with differences at the genus level during the Guadalupian and Lopingian. Three provinces of Permian conodonts, referred to as the North Cool Water Province (NCWP), the Equatorial Warm Water Province (EWWP) and the peri-Gondwana Cool Water Province (GCWP), are recognized. The NCWP is marked by Gondolelloides in the early Cisuralian, dominance of Neostreptognathodus and no or rare Sweetognathus in the late Cisuralian, dominance of Merrillina and Mesogondolella and absence of Sweetognathus in the Guadalupian, and dominance of Merrillina and Mesogondolella and absence of Iranognathus in the Lopingian. The EWWP is characterized by the absence of Gondolelloides and Vjalovognathus in the Cisuralian, abundance of Sweetognathus and Pseudosweetognathus in the Kungurian (late Cisuralian), Jinogondolella and Sweetognathus in the Guadalupian, and Clarkina and Iranognathus in the Lopingian. The GCWP is marked by Vjalovognathus, Merrillina in the Cisuralian, Vjalovognathus, Merrillina and Mesogondolella in the Guadalupian, and Vjalovognathus and Merrillina in the Lopingian. Mixed faunas are recognized in regions bordering between the EWWP and GCWP including Western Timor during the Artinskian, Pamirs during the Kungurian and the Salt Range during the Guadalupian and Lopingian.

Three different conodont zonations are proposed, one for each of the three conodont provinces. Four potential horizons for inter-provincial correlation of Permian conodonts are recognized. They are in ascending order: (1) the first appearance of Sweetognathus whitei, which is closely related to the last occurrence of Carboniferous-type conodonts such as Streptognathodus and Adetognathus; (2) the first appearance of Neostreptognathodus pequopensis; (3) the base of the Jinogondolella nankingensis Zone; and (4) the base of the Clarkina postbitteri–Iranognathus erwini Zone.

The spatial and temporal distribution pattern of Permian conodonts suggests that temperature is the primary controlling factor. Evolution of Permian conodont provincialism reveals a glaciation during the Asselian and Sakmarian, a global warming during the Artinskian, a climate cooling in North Pangea during the Kungurian, a continuation of Kungurian climate trends in the Guadalupian, a relatively minor warming during the Wuchiapingian, a returned cooling in the Changhsingian and Lower and Middle Griesbachian, and a global warming in the Late Griesbachian, which ended the Permian conodont lineage.