Xinglian Yang

The occurrence of the genus Marrella (Trilobitoidea) in Asia

Abstract An important discovery in the Kaili Biota has been made recently, and many interesting components from Chengjiang Biota and Burgess Shale Biota have been discovered. Among them Marrella, only known from mid-Middle Cambrian Burgess Shale Biota of British Columbia, Canada, is one of the most important arthropods fossils. Because the Kaili Biota is older than the Burgess Shale Biota, the strange head shield of Marrella occurring in the Kaili Biota outside Laurentia ranges from mid-Middle Cambrian to early Middle Cambrian and is significant for the reconstruction of palaeogeography and evolutionary study of early metazoa. In the present paper Marrella sp. is reported for the first time in Asia.

Meteorological observations on Mount Everest in 2005

Abstract Mount Everest, the highest point on the Earth is often referred to as the earths third pole as such the place is relatively inaccessible and little is known about its meteorology. In April 2005, an automatic weather station was installed as the mountains North Col (6523 m a. s. l.). According to the observational 10-minute mean and daily records, the meteorological characteristics were analyzed. All the meteorological elements displayed obvious diurnal variations during May 1 to July 22, 2005. The monthly variation of daily meteorological elements on Mount Everest coincided with that on Dingri, the closest routine meteorological station, with the high correlation co-efficients of 0.928, 0.877, 0.682, 0.755, 0.826 and 0.676 (n = 83, p < 0.001) for mean temperature, minimum temperature, maximum temperature, relative humidity, pressure and wind speed, respectively. Furthermore, the vertical mean gradient of temperature was above 0.6°C/100 m, especially for the daily maximum temperature. Most weath...

Comments on some important issues concerning the establishment of a GSSP for Cambrian Stage 5

In order to help facilitate stratigraphic correlation between south China and Siberia, trilobite zones of Guizhou, China, and the Molodo River area, Siberia, need to be better coordinated. The Wuliu-Zengjiayan section is a strong candidate for the Global Standard Stratotype Section and Point for Cambrian Stage 5, and the Molodo River section provides important supplemental information that helps expand the precision of correlation on a global scale. The Kaili Formation in the Wuliu-Zengjiayan section contains three trilobite zones over an interval of 214.20 m. We propose that the Ovatoryctocara granulata Zone, as used in Siberia, replace the Ovatoryctocara Zone. Equivalent strata in Guizhou extend more than 150 m stratigraphically, from the Protoryctocephalus wuxunensis Zone to the Bathynotus kueichouensis–O. cf. O. granulata Assemblage Zone. We also propose that the traditional Kounamkites Zone be supplemented or replaced by the Oryctocephalus reticulatus Zone, which outside Siberia contains Oryctocephalus indicus.

Diachronous Increase in Early Cambrian Ichnofossil Size and Benthic Faunal Activity in Different Climatic Regions

Abstract In order to clarify the pattern of diversification and processes of biological activity during the Cambrian radiation, ichnofossils were comparatively studied in the early Cambrian sections of Newfoundland, South China and western Mongolia. Special attention was paid to size distributions of the most common ichnogenus, Planolites, and the densities of all the observed ichnofossils that preserve animal activity as expressed by bedding plane bioturbation indices (BPBI). From the Fortune Head section in Newfoundland, a clear size increase in the ichnogenus Planolites is confirmed from the Treptichnus pedum Zone to the overlying Rusophycus avalonensis Zone. The BPBI also shows much stronger biological activity in the R. avalonensis Zone than in the T. pedum Zone. In Meishucun, South China and Gobi-Altai, Mongolia, however, a variety of Planolites sizes had already appeared in the T. pedum Zone, and the BPBIs on some bedding surfaces of the T. pedum Zone are already comparable to those in the R. avalonensis Zone in Newfoundland. In the earliest Cambrian, diversification and increase in the biological activity of the benthic fauna were diachronous in the wide geographic scale, starting earlier at lower latitudes (South China and western Mongolia) than at higher latitudes (Newfoundland), reflecting differences in the onset of Cambrian benthic animal activity under different climatic conditions.

The trilobite Bathynotus from Cambrian Series 2 of China and its implications for global correlation

The trilobite Bathynotus kueichouensis is widespread, occurring in Siberia, South China, North America and Australia. With a short stratigraphic range and widespread geographic distribution, it is useful for marking the top of Cambrian Series 2 and provides important information for precise correlation of the top of the series.

A new vauxiid sponge from the Kaili Biota (Cambrian Stage 5), Guizhou, South China

The skeleton of a new vauxiid sponge (Order Verongida), Angulosuspongia sinensis gen. et sp. nov., described on the basis of material from calcareous mudstones of the Kaili Formation (Cambrian Stage 5), Jianhe area, Guizhou, South China, is composed of two layers of fused spicules outlining hexagonal or polygonal openings. These vauxiid remains are the first reported from outside Laurentia, and represent only the second genus attributed to the family. Its age is close to but still slightly older than the Burgess Shale Biota, and it appears to be a primitive relative of other members of the Vauxiidae. The morphological differences between Chinese and Laurentian vauxiid sponges may be a result of vicariance. These specimens not only extend the geographic distribution of vauxiids, but also help to fill a chronostratigraphical gap between North Greenland and North American material and provide additional evidence for understanding the evolutionary history of the Demospongiae.

Geochemistry of the trace elements and rare-earth elements at the boundary between Cambrian Series 2 and Series 3 at Jianshan, South China: Paleoenvironmental and stratigraphic implications

The Jianshan section in Jianhe County, Guizhou Province, is a very important auxiliary section to the candidate stratotype at the boundary between Cambrian Series 2 and Series 3. Twenty four samples collected from the Jianshan section of the Kaili Formation were analyzed for the concentrations of trace element and rare-earth elements (REEs) by inductively coupled plasma mass spectrometry. The trace element and REE geochemical characteristics of the Kaili Formation at the Jianshan section show that trace element composition and REE distribution patterns across the section are covariant. Notably, at 44 m above the base of the Kaili Formation, most trace element contents and REEs concentrations are lower than those values observed below 44 m. Above 44 m, an increasing trend in the concentration of both trace elements and REEs is observed. These geochemical data indicate important, but subtle, changes at the 44 m horizon. If this is, in fact, verified by work in progress, geochemical criteria can provide additional supports for defining the top surface of Cambrian Series 2, especially in sections where Oryctocephalus indicus is absent. Trace element ratios, specifically Ni/Co, V/Cr, V/(Ni+V) and Th/U as well as Ce and Eu anomalies indicate that the sedimentary environment of the Kaili Formation at the Jianshan section was oxidizing, that benthic redox conditions were less oxic, and may have been influenced by freshwater as compared to the Balang area. Moreover, the Eu anomalies observed in the Kaili Formation are similar to the negative Eu anomalies observed in post-Archean sedimentary rocks, and reveal fluctuations in oxygen content from the bottom to the top of the Kaili Formation.

Paleoecological Significance of Complex Fossil Associations of the Eldonioid Pararotadiscus guizhouensis with other Faunal Members of the Kaili Biota (Stage 5, Cambrian, South China)

Abstract The planktonic medusiform taxon Pararotadiscus guizhouensis (Zhao and Zhu, 1994) is one of the most abundant components of the Kaili Biota. Many specimens are in direct association with other taxa, including trilobites, brachiopods, hyolithids, echinoderms, and algae, as well as the trace fossil Gordia. Four types of interrelationships between P. guizhouensis and associated fossils are recognized: symbiosis, co-burial, attachment of benthic taxa on P. guizhouensis carcasses, and scavenging of P. guizhouensis carcasses. These associations of P. guizhouensis within the Kaili Biota are unique among occurrences of medusiform fossils in Burgess Shale-type biotas worldwide and provide important insights concerning ecological complexity in the Kaili Biota and in Cambrian marine communities in general.