Guang Rong Shi

Multivariate data analysis in palaeoecology and palaeobiogeography-a review

Abstract Palaeoecologists and palaeobiogeographers are often confronted with large, multivariate data sets, from which fossil communities (assemblages or associations) or faunal provinces are to be recognized. The complex, multidimensional nature of these data sets, the recognition of the enormous variation of communities and environments both in space and time, and the difficulties of dealing with these problems by the human mind, justify the use of multivariate statistical methods in palaeoecology and palaeobiogeography. Concepts and basic procedures of several commonly used multivariated statistical methods of palaeoecology and palaeobiogeography are reviewed in the wider context of quantitative community ecology and biogeography, basic assumptions about data structure and theoretical and practical limitations are discussed. The emphasis is on evaluation of binary similarity coefficients and two multivariate approaches: cluster analysis and ordination. Thirty-nine binary similarity coefficients are evaluated against nine criteria, Jaccards coefficient of community is found most suitable as a similarity measure between samples under the conditions tested. Algorithmic procedures of cluster analysis, especially the agglomerative hierarchical cluster analysis techniques, and indirect ordinations (particularly polar ordination, principal component analysis, principal coordinate analysis, correspondence analysis, detrended correspondence analysis, and nonmetric multidimensional scaling) are outlined and their applicability to palaeoecological and palaeobiogeographical data is discussed. Where the data are appropriate, an integration of cluster analysis and ordination is suggested to be applied to the same data.

End-Permian catastrophe by a bolide impact: Evidence of a gigantic release of sulfur from the mantle

Our studies in southern China have revealed a remarkable sulfur and strontium isotope excursion at the end of the Permian, along with a coincident concentration of impact- metamorphosed grains and kaolinite and a significant decrease in manganese, phosphorous, calcium, and microfossils (foraminifera). These data suggest that an asteroid or a comet hit the ocean at the end of Permian time and caused a rapid and massive release of sulfur from the mantle to the ocean-atmosphere system, leading to significant oxygen consumption, acid rain, and the most severe biotic crisis in the history of life on Earth.

Distribution and characteristics of mixed (transitional) mid-Permian (Late Artinskian—Ufimian) marine faunas in Asia and their palaeogeographical implications

Abstract The Permian marine biogeography of the Asian region is characterised by the development of three broad realms (Boreal, Tethyan and Gondwanan). In the early Early Permian (Asselian to Early Artinskian), there seems to have existed sharp biogeographical boundaries with no transitional zones between the realms, presumably due to the effect of Gondwanan glaciation and sharp climatic zonation. The mid-Permian (Late Artinskian to Ufimian) of the Asian region is distinguished by the rise of two broad transitional zones in which mixed marine faunas flourished. The northern transitional zone (north and northeast China, Sikhote Alin, central and northeast Japan) is characterised by an admixture of both warm-water Cathaysian and cold temperate Boreal genera. The southern transitional zone (Arabian Peninsula, Iran, Afghanistan, the Karakorum, southeast and central Pamir, Salt Range, central and northwest Tibet, Shan-Thai terrane, Timor, and western Irian Jaya), on the other hand, is distinguished by incorporating faunal elements of both Gondwanan and Cathaysian origin. The mixed faunas of both transitional zones share several antitropically distributed genera (e.g., Monodiexodina, Lytvolasma and Spiriferella ) and are succeeded by palaeotropical Tethyan faunas of Late Permian age. It has been postulated that the mixed mid-Permian fauna of the northern transitional zone was probably formed in an epicontinental sea which was connected to both the Asian Tethys and the Arctic, which facilitated the migration of Cathaysian and Boreal forms into the epicontinental sea and subsequent faunal mixing. The formation of the mixed faunas of the southern transitional zone, on the other hand, is probably related to the breaking off of the Cimmerian blocks from northern Gondwana and subsequent drifting into a lower latitudinal zone with geographical proximity to both Gondwana and Cathaysia during the mid-Permian.

Paleobiogeographical extinction patterns of Permian brachiopods in the Asian-western Pacific region

Abstract Spatial and temporal variations in biological diversity are critical in understanding the role of biogeographical regulation (if any) on mass extinctions. An analysis based on a latest database of the stratigraphic ranges of 89 Permian brachiopod families, 422 genera, and 2059 species within the Boreal, Paleoequatorial, and Gondwanan Realms in the Asian–western Pacific region suggests two discrete mass extinctions, each possibly with different causes. Using species/family rarefaction analysis, we constructed diversity curves for late Artinskian–Kungurian, Roadian–Wordian, Capitanian, and Wuchiapingian intervals for filtering out uneven sampling intensities. The end-Changhsingian (latest Permian) extinction eliminated 87–90% of genera and 94–96% of species of Brachiopoda. The timing of the end-Changhsingian extinction of brachiopods in the carbonate settings of South China and southern Tibet indicates that brachiopods suffered a rapid extinction within a short interval just below the Permian/Triassic boundary. In comparison, the end-Guadalupian/late Guadalupian extinction is less profound and varies temporally in different realms. Brachiopods in the western Pacific sector of the Boreal Realm nearly disappeared by the end-Guadalupian but experienced a relatively long-term press extinction spanning the entire Guadalupian in the Gondwanan Realm. The end-Guadalupian brachiopod diversity fall is not well reflected at the timescale used here in the Paleoequatorial Realm because the life-depleted early Wuchiapingian was overlapped by a rapid radiation phase in the late Wuchiapingian. The Guadalupian fall appears to be related to the dramatic reduction of habitat area for the brachiopods, which itself is associated with the withdrawal of seawater from continental Pangea and the closure of the Sino-Mongolian seaway by the end-Guadalupian.

Diversity and extinction patterns of Permian Brachiopoda of South China

The stratigraphical and geographical distribution of 851 brachiopod species from 216 genera and 65 families in the Permian of South China are analysed. It is revealed that the brachiopod diversity underwent two sharp falls during the Permian. The first occurred at the end of Maokouan, accompaning the widely recognised, extensive regression across the Maokouan‐Wujiapingian boundary. Fifty‐seven species of 29 genera survived this first major extinction event. The second sharp reduction of brachiopod diversity took place in the later Changhsingian, with only 17 Permian‐type brachiopod species of 12 genera straggling into the earliest Triassic. Detailed stratigraphic analysis shows that more than 90% of the Changhsingian brachiopod species disappeared at different levels in the Changhsingian before the widely perceived end‐Permian ‘mass extinction’ occurred. It is also notable that each of the step‐wise diversity reduction events was apparently heterochronous. In view of the evidence from lithologies, faunal ...

Palynological and stable isotopic study of palaeoenvironmental changes on the northeastern Tibetan plateau in the last 30,000 years

Abstract The Tibetan Plateau is important in influencing the atmospheric circulation of the Northern Hemisphere. However, only a few continuous palaeoclimate records are available. Here, we present a 30,000 year pollen and carbon stable-isotope record of two lacustrine sections from the Zoige Plateau on the northeastern Tibetan Plateau. The pollen spectra show that the territorial palaeovegetational evolution experienced 7 stages in the following order: (1) 30.0 (?)–26.0 kyr B.P., alpine desert and desert–grassland vegetation; (2) 26.0–18.0 kyr B.P., grassland and alpine meadow vegetation; (3) 18.0–14.2 kyr B.P., alpine desert; (4) 14.2–10.0 kyr B.P., grasslands and meadows with islet forests; (5) 10.0–9.4 kyr B.P., marsh and meadow vegetation; (6) 9.4–4.0 kyr B.P., dark conifer islet and marsh; and finally (7) 4.0 kyr B.P.–present, marsh and subalpine meadows with scattered islets of dark conifer. The palaeoclimate was inferred from these variations in palaeovegetation, and in particular, the variation in the last 12,000 years was confirmed by the δ 13 C curve of the No. 2 pit section. Major post-glacial climatic events are clearly identified in the two study sequences, including the Late Glacial series of Bolling, Allerod, Old Dryas and Younger Dryas, and the Holocene Optimum. The climate records in the two sequences also indicate a long-term trend towards aridity in the study area.

Pyrite framboids interpreted as microbial colonies within the Permian Zoophycos spreiten from southeastern Australia

Two types of pyrite framboids (PF, probably sulphate-reducing bacteria) have been found within the Zoophycos spreiten, hosted in the Guadalupian (Middle Permian) glaciomarine greywacke of the Westley Park Sandstone Member within the Broughton Formation from the southern Sydney Basin of southeastern Australia. They are composed of non-sheathed (PF1) and sheathed (PF2) sub-micron balls, respectively. Chemically, the sub-micron balls consist of iron, sulphur, carbon and oxygen. Both PF1 and PF2 occur in rhythmic alternation within the thick, light-grey and thin, dark-grey minor lamellae of Zoophycos spreiten. The framboids from the minor lamellae are highly abundant and occur in an orderly arrangement of equal density and in a good state of preservation. Within Zoophycos spreiten no homogeneous filling, fecal pellets, or any sign of re-exploitation of the minor lamellae have been recognized. No similar framboids have been observed outside Zoophycos spreiten. Therefore, the framboids are interpreted as the pyritized remains of microbial colonies within Zoophycos spreiten. The trace Zoophycos would be a multifunctional garden that may have been carefully constructed by the Zoophycos maker, where different microbial colonies were orderly and carefully planted and cultured within different minor lamellae. Further, it is proposed that the Zoophycos maker had a symbiotic relationship with microbial colonies on the mutual basis of food supply and redox conditions. The fact that the overlying spreiten cut the underlying ones indicates that the Zoophycos from the study area is of an upward construction. The rhythmic alternation of both the thick, light-grey and thin, dark-grey minor lamellae within Zoophycos spreiten may be suggestive of a gardening manner of the Zoophycos maker responding to the warm and cold changes, food supply in pulses and variations of sedimentation rate for planting and culturing microbial colonies under the conditions of a glaciomarine environment at the high latitudes.

Wuchiapingian (early Lopingian, Permian) global brachiopod palaeobiogeography: a quantitative approach

Abstract A global presence/absence database of 212 Wuchiapingian (early Lopingian, Permian) brachiopod genera from 30 stations is analysed by cluster analysis, nonmetric multidimensional scaling and minimum spanning tree to document the global palaeobiogeographical patterns. Five core groups are revealed by the quantitative analysis and interpreted as representing five marine biotic provinces. They are the Cathaysian (tropical), Western Tethyan (tropical), Himalayan (warm temperate), Austrazean (cold temperate) and Greenland–Svalbard Provinces (cold temperate). The Cathaysian Province is composed of many isolated or semi-isolated islands situated in the Palaeotethys, whereas the other four provinces occurred mainly on the continental shelves of Pangea: the Western Tethyan Province along the western coast of the Palaeotethys, the Himalayan Province on the northern margin of Gondwanaland, the Austrazean Province along the southeastern margin of Gondwanaland, and the Greenland–Svalbard Province on the northern margin of Pangea. In addition, nonmetric multidimensional scaling helped to identify key biogeographic determinants: latitude-related thermal gradient appears to have accounted for most of the variance in the data; geographic distance and ocean circulation may have also played a major, but subordinate, role in the delineation and/or enhancement of some of the provinces. Comparison with Early and Middle Permian global marine provincialism indicates that marine biotic provinces had significantly reduced during the Lopingian (Late Permian) in the lead up to the end-Permian mass extinction.

Late Paleozoic depositional history of the Tarim basin, northwest China: An integration of biostratigraphic and lithostratigraphic constraints

This study provides the first detailed lithostratigraphic and biostratigraphic constraints for improving stratigraphic resolution for hydrocarbon prospecting and exploration in the Tarim basin. A total of 49 stratigraphic units (38 formations and 11 members), ranging in age from the latest Devonian to Permian, are reviewed or redefined in terms of nomenclatures, lithology, age constraints, and lateral distributions based on the detailed field works or newly published data. Of these, the Piqiang Formation (new formation) is proposed to include the reefal carbonates of Asselian–Sakmarian age from the northern Tarim. The subsurface upper Paleozoic stratigraphic framework of the desert areas of the basin is also established for the first time. The high-resolution, basinwide stratigraphic correlations reveal that the sedimentation of the basin in the late Paleozoic was extremely uneven. Of these, the Famennian to Changhsingian successions are completely recorded in the southwestern margin areas of the basin. Here, five eustatic sedimentary cycles are well recognizable, suggesting the sedimentation was more eustatically controlled and little affected by local tectonism. The late Paleozoic successions of both Kalpin and Taklimakan regions are commonly interrupted by major hiatuses at various horizons, suggesting that the sedimentation was apparently modified by local tectonism. Of these, the northward movement of the Tarim block and its subsequent collision with the Yili microcontinent (part of the Kazakhstan plate) may be principally accountable for the discrepancy in the sedimentation of the various regions in the basin in the late Paleozoic.

Western Pacific Permian marine invertebrate palaeobiogeography

Data matrices of the presence/absence occurrence data of brachiopod genera from faunal stations throughout the western Pacific region for the Asselian‐Tastubian, Sterlitamakian‐Aktastinian, Baigendzhinian‐Early Kungurian and Kazanian‐Midian time slices of the Permian Period have been analysed by cluster analysis, non‐metric multidimensional scaling and principal coordinate analysis. An evolving pattern of provincialism is recognised for the Permian of the western Pacific with four provinces (Indoralian, Himalayan, Cathaysian and Verkolyma) for the Asselian‐Tastubian, six (Austrazean, Westralian, incipient Cimmerian, Cathaysian, Sino‐Mongolian precursor and Verkolyma) for the Sterlitamakian‐Aktastinian, seven (Austrazean, Westralian, Cimmerian‐with the Sibumasu and Himalayan subprovinces‐Cathaysian, Sino‐Mongolian and Verkolyma) for the Baigendzhinian‐Early Kungurian, and three (Austrazean, Cathaysian and Verkolyma) for the Kazanian‐Midian time slice. The changing pattern of provincialism is best understoo...