Calcified biofiims are preserved as thin micritic coatings in the Cambrian oolitic limestone of two sections in North and South China. Standard petrographic examination revealed that the biofilms were developed during...Calcified biofiims are preserved as thin micritic coatings in the Cambrian oolitic limestone of two sections in North and South China. Standard petrographic examination revealed that the biofilms were developed during the early diagenetic stage immediately after the freshly deposited ooids, proceeding in the continuous sequence of depositional processes. The biofilm outlines are highly irregular, with steep sides, tower-like structures and overhanging projections; the internal fabric of the biofilms is composed of roughly laminated micrite aggregates with channel-like structures. Biofilms exhibit a strong fluorescent reaction. Detailed SEM examination suggests that the biofilms are biotically dominated by cyanobacteria. Our study demonstrates that microbial colonies, such as biofilms, can develop on ooid cortices and influence the formation and microstructures of those ooids.展开更多
Phosphatized and three-dimensionally preserved embryos and spherical fossils of metazoan recovered from the Kuanchuanpu Member, Dengying Formation in southern Shaanxi, China provide nice devel- opmental sequence for t...Phosphatized and three-dimensionally preserved embryos and spherical fossils of metazoan recovered from the Kuanchuanpu Member, Dengying Formation in southern Shaanxi, China provide nice devel- opmental sequence for the studies of origination, taxonomy, phylogenic evolution and developmental biology of early animals. Ontogeny of these larva fossils has not been systemically studied mainly due to their poor preservation and limited identification. The Kuanchuanpu Member, predominated by phosphorites and cherts, yields phosphatized animal embryos, particularly those of Olivooides and Punctatus which have high resolution in fine structures and different ontogeny developmental stages. An ontogenetic sequence of the Punctatus is established mainly base on its developmental transitions from body part to oral one, which is perfectly consistent with the embryonic ontogeny sequence pro- posed by Bengtson and Yue (1997). Furthermore, a new genus Quadrapyrgites gen. nov is erected to receive a larva with tetraradial body plan.展开更多
Marine invertebrate animal embryos and their early developmental products are of great significance to the study of taxonomy and phylogeny of early animals. A great number of phosphatized globular fossils were collect...Marine invertebrate animal embryos and their early developmental products are of great significance to the study of taxonomy and phylogeny of early animals. A great number of phosphatized globular fossils were collected fromthe early Cambrian Kuanchuanpu Member (upper Dengying Formation), southern Shaanxi, and a nearly complete develo-pmental sequence—from a fertilized egg, via blastodisc formation, blastula development, blastodisc enlargement toward gastrulae, to tissue differentiation—can be discerned in this collection. This discovery provides unmatchable material for studies on the origin, taxonomy, radiation, and ontogeny of early metazoans.展开更多
Middle and Late Cambrian trilobite faunas from the Dama section in western Hunanare are composed of 63 genera and subgenera, 84 species, and two forms of gen. et sp. indetermined. Which include a mixture of cosmopolit...Middle and Late Cambrian trilobite faunas from the Dama section in western Hunanare are composed of 63 genera and subgenera, 84 species, and two forms of gen. et sp. indetermined. Which include a mixture of cosmopolitan agnostoids and polymeroids. Three new species,Hardyoides damaensis,Meringaspis damaensis and Rhyssometopus (Rodtrifinis) nitidus, are described by present author in 2004. Besides, Erixanium is recognised for the first time in study area, which is significant for biostratigraphical correlation of the Late Cambrian in the Austalo-Asia region. According to distribution regularity vertical, the Middle and Late Cambrian trilobites can be divided into 9 trilobite communities for the Dama section. Based on the trilobite communities analysis, the author concludes that from the east Mt. Lailong to Dama through Fenghuang, further east, reach in Chenxi,the palaeoenvironments were changed from a shallow-water of oxygen-rich (platform margin slope ) into a deep-water of oxygen-poor setting (basin).展开更多
The Cambrian rocks are well exposed along the Kurgiakh-Surichun La section,situated 78 km SE of the Padam Village along a track route at 33°03′787″N and 77°013′647″E in between the Kurgiakh and Surichun ...The Cambrian rocks are well exposed along the Kurgiakh-Surichun La section,situated 78 km SE of the Padam Village along a track route at 33°03′787″N and 77°013′647″E in between the Kurgiakh and Surichun La,in Kurgiakh Valley(southeastern Zanskar).Around 715 m thick Cambrian succession was measured along the right and left banks of展开更多
In Korea, trilobites are among the most intensively studied fossil groups in the past century and provide invaluable information about lower Paleozoic stratigraphy, paleogeography, and tectonics of the Korean Peninsul...In Korea, trilobites are among the most intensively studied fossil groups in the past century and provide invaluable information about lower Paleozoic stratigraphy, paleogeography, and tectonics of the Korean Peninsula. Trilobites occur in the lower Paleozoic Joseon Supergroup of the Taebaeksan Basin which was part of the Sino-Korean Craton in the Paleozoic. The Joseon Supergroup is divided into the Taebaek, Yeongwol, and Mungyeong groups. The Taebaek and Yeongwol groups are richly fossiliferous, while the Mungyeong Group is poorly fossiliferous. Contrasting trilobite faunal contents of the Taebaek and Yeongwol groups resulted in two separate biostratigraphic schemes for the Cambrian–Ordovician of the Taebaeksan Basin. A total of 22 biozones or fossiliferous horizons were recognized in the Taebaek Group; 19 zones were established in the Yeongwol Group; and four biozones were known from the Mungyeong Group. These trilobite biozones of the Taebaeksan Basin indicate the Joseon Supergroup ranges in age from the Cambrian Series 2 to Middle Ordovician and can be correlated well with the formations of North China, South China, and Australia.展开更多
Biostratigraphy and chronostratigraphy are common means of subdividing rock strata. The biostratigraphic succession and chronostratigraphic scheme are regarded as the basis for the subdivision and correlation of regio...Biostratigraphy and chronostratigraphy are common means of subdividing rock strata. The biostratigraphic succession and chronostratigraphic scheme are regarded as the basis for the subdivision and correlation of regional and global stratigraphic units. This paper reviews research on the biostratigraphy and chronostratigraphy carried out in the Jiangnan Slope Belt, South China since 1978, and, in particular, the biostratigraphic succession and chronostratigraphic scheme developed in the last decade. The updated biostratigraphic succession of South China includes 36 biozones, the base of each of which is defined by the first appearance of a single taxon (index fossil), and a poorly fossiliferous interzone. The updated chronostratigraphic scheme of South China comprises 4 series and 10 stages, embracing 3 global chronostratigraphic units, the Guzhangian Stage, Furongian Series, and Paibian Stage, and 2 GSSPs, all of which are erected in northwestern Hunan and 2 International Tie Points recognized in sections also in northwestern Hunan and each was accepted by the International Subcommission on Cambrian Stratigraphy for defining the base of the global stage. The biostratigraphic and chronostratigraphic systems are recognized as Chinese standards both domestically and worldwide. Future research is suggested for improving the two sets of stratigraphic standards.展开更多
基金financial support from the Major Basic Research Project of the Ministry of Science and Technology of China(Grant:2013CB835002)the Natural Science Foundation of China(Grants:41272036)+1 种基金the China Postdoctoral Science Foundation(Grant:2014M552481)the"Sanqin Scholarship"project of the Shaanxi Authority
文摘Calcified biofiims are preserved as thin micritic coatings in the Cambrian oolitic limestone of two sections in North and South China. Standard petrographic examination revealed that the biofilms were developed during the early diagenetic stage immediately after the freshly deposited ooids, proceeding in the continuous sequence of depositional processes. The biofilm outlines are highly irregular, with steep sides, tower-like structures and overhanging projections; the internal fabric of the biofilms is composed of roughly laminated micrite aggregates with channel-like structures. Biofilms exhibit a strong fluorescent reaction. Detailed SEM examination suggests that the biofilms are biotically dominated by cyanobacteria. Our study demonstrates that microbial colonies, such as biofilms, can develop on ooid cortices and influence the formation and microstructures of those ooids.
基金Supported by the National Natural Science Foundation of China (Grant Nos. 40572015 and 40332016)Ministry of Science and Technology of China (Grant No. 2006CB806400)+1 种基金Program for Changjiang Scholars and Innovative Research Team in University (PCSIRT)Program for New Century Excellent Talents in University, and National Basic Science Personnel Training Foundation (Grant No. J0630537)
文摘Phosphatized and three-dimensionally preserved embryos and spherical fossils of metazoan recovered from the Kuanchuanpu Member, Dengying Formation in southern Shaanxi, China provide nice devel- opmental sequence for the studies of origination, taxonomy, phylogenic evolution and developmental biology of early animals. Ontogeny of these larva fossils has not been systemically studied mainly due to their poor preservation and limited identification. The Kuanchuanpu Member, predominated by phosphorites and cherts, yields phosphatized animal embryos, particularly those of Olivooides and Punctatus which have high resolution in fine structures and different ontogeny developmental stages. An ontogenetic sequence of the Punctatus is established mainly base on its developmental transitions from body part to oral one, which is perfectly consistent with the embryonic ontogeny sequence pro- posed by Bengtson and Yue (1997). Furthermore, a new genus Quadrapyrgites gen. nov is erected to receive a larva with tetraradial body plan.
文摘Marine invertebrate animal embryos and their early developmental products are of great significance to the study of taxonomy and phylogeny of early animals. A great number of phosphatized globular fossils were collected fromthe early Cambrian Kuanchuanpu Member (upper Dengying Formation), southern Shaanxi, and a nearly complete develo-pmental sequence—from a fertilized egg, via blastodisc formation, blastula development, blastodisc enlargement toward gastrulae, to tissue differentiation—can be discerned in this collection. This discovery provides unmatchable material for studies on the origin, taxonomy, radiation, and ontogeny of early metazoans.
文摘Middle and Late Cambrian trilobite faunas from the Dama section in western Hunanare are composed of 63 genera and subgenera, 84 species, and two forms of gen. et sp. indetermined. Which include a mixture of cosmopolitan agnostoids and polymeroids. Three new species,Hardyoides damaensis,Meringaspis damaensis and Rhyssometopus (Rodtrifinis) nitidus, are described by present author in 2004. Besides, Erixanium is recognised for the first time in study area, which is significant for biostratigraphical correlation of the Late Cambrian in the Austalo-Asia region. According to distribution regularity vertical, the Middle and Late Cambrian trilobites can be divided into 9 trilobite communities for the Dama section. Based on the trilobite communities analysis, the author concludes that from the east Mt. Lailong to Dama through Fenghuang, further east, reach in Chenxi,the palaeoenvironments were changed from a shallow-water of oxygen-rich (platform margin slope ) into a deep-water of oxygen-poor setting (basin).
文摘The Cambrian rocks are well exposed along the Kurgiakh-Surichun La section,situated 78 km SE of the Padam Village along a track route at 33°03′787″N and 77°013′647″E in between the Kurgiakh and Surichun La,in Kurgiakh Valley(southeastern Zanskar).Around 715 m thick Cambrian succession was measured along the right and left banks of
基金supported by a grant from the National Research Foundation of Korea(Grant No.NRF-2014R1A1A2002851)
文摘In Korea, trilobites are among the most intensively studied fossil groups in the past century and provide invaluable information about lower Paleozoic stratigraphy, paleogeography, and tectonics of the Korean Peninsula. Trilobites occur in the lower Paleozoic Joseon Supergroup of the Taebaeksan Basin which was part of the Sino-Korean Craton in the Paleozoic. The Joseon Supergroup is divided into the Taebaek, Yeongwol, and Mungyeong groups. The Taebaek and Yeongwol groups are richly fossiliferous, while the Mungyeong Group is poorly fossiliferous. Contrasting trilobite faunal contents of the Taebaek and Yeongwol groups resulted in two separate biostratigraphic schemes for the Cambrian–Ordovician of the Taebaeksan Basin. A total of 22 biozones or fossiliferous horizons were recognized in the Taebaek Group; 19 zones were established in the Yeongwol Group; and four biozones were known from the Mungyeong Group. These trilobite biozones of the Taebaeksan Basin indicate the Joseon Supergroup ranges in age from the Cambrian Series 2 to Middle Ordovician and can be correlated well with the formations of North China, South China, and Australia.
基金Supported by the Key-Direction Project of Knowledge Innovation Program, Chinese Academy of Sciences (Grant No. KZCX2-YW-122)National Basic Research Pro-gram of China (Grant No. 2006CB806400, 2006FY120300)National Natural Science Foundation of China (Grant Nos. 40023002 and 400332018)
文摘Biostratigraphy and chronostratigraphy are common means of subdividing rock strata. The biostratigraphic succession and chronostratigraphic scheme are regarded as the basis for the subdivision and correlation of regional and global stratigraphic units. This paper reviews research on the biostratigraphy and chronostratigraphy carried out in the Jiangnan Slope Belt, South China since 1978, and, in particular, the biostratigraphic succession and chronostratigraphic scheme developed in the last decade. The updated biostratigraphic succession of South China includes 36 biozones, the base of each of which is defined by the first appearance of a single taxon (index fossil), and a poorly fossiliferous interzone. The updated chronostratigraphic scheme of South China comprises 4 series and 10 stages, embracing 3 global chronostratigraphic units, the Guzhangian Stage, Furongian Series, and Paibian Stage, and 2 GSSPs, all of which are erected in northwestern Hunan and 2 International Tie Points recognized in sections also in northwestern Hunan and each was accepted by the International Subcommission on Cambrian Stratigraphy for defining the base of the global stage. The biostratigraphic and chronostratigraphic systems are recognized as Chinese standards both domestically and worldwide. Future research is suggested for improving the two sets of stratigraphic standards.
