Details

Autor(en) / Beteiligte

• Liu, Bingchen
• Dai, Mingyue
• Qi, Yong’an
• Sun, Xiaofang
• Zheng, Wei
• Wang, Min
• Xing, Zhifeng
• Li, Da
• Fan, Yuchao

Titel

Alternation of stromatolites and vertical burrows controlled by storm processes and sea-level changes in the middle Cambrian carbonates of central China

Ist Teil von

• Journal of Earth System Science, 2022-03, Vol.131 (1), p.65, Article 65

Ort / Verlag

New Delhi: Springer India

Erscheinungsjahr

2022

Quelle

SpringerLink

Beschreibungen/Notizen

• The rapid beginning of modern phyla in the Early Cambrian, which is known as the Cambrian explosion, represents one of the most dramatic episodes in the history of the biosphere. During this period, microbes and metazoans coevolved notably under the influence of the environment, and microbiogenic structures and bioturbated structures tended to alternate in the strata, forming a unique Cambrian ecological landscape. A large number of biogenic structures occurred in the carbonates of the Mantou formation (Cambrian series 3) in the Dengfeng complex, western Henan, China. The microbially induced stromatolites are preserved in marlstone and mostly grow upwards on irregular erosive storm surfaces. Stromatolites are laterally discontinuous and dominated by a columnar shape, which locally display inverted cone and finger-like or irregular shapes; they formed in the intertidal zone under alternating high- and low-energy hydrodynamic conditions. The vertical Skolithos burrows and U-shaped Arenicolites occur widely in oolitic limestones, forming Skolithos piperock. Additionally, the clear linings indicate that the burrows represent permanent domiciles of suspension feeders and passive predators and were formed in a high-energy near-shore oolitic beach environment. The microbially induced stromatolites and the metazoan-produced vertical burrows were alternately developed in the carbonate rocks of the Mantou formation, indicating that the Cambrian was a period of co-prosperity of microbes and metazoans, and the development of microbiogenic structures and bioturbated structures was obviously controlled by environmental conditions. In the Cambrian carbonate rocks, the microbial rocks and metazoan-disturbed limestones or bioclastic limestones coexist and show a trend of change. The marine sedimentary substrates are characterised by alternate development of tough matgrounds and soft mixgrounds. The special characteristics of sedimentary substrates reveal that the ‘Cambrian substrate revolution’ was probably a protracted process operating during the entire Cambrian period. Research highlights Stromatolites grow around the oolitic conglomerates formed by storm action. Metazoans colonize the intertidal zone during intervals between storms. Microorganisms appear in stable water environment before metazoans. Alternation of stromatolites and vertical burrows controlled by storm processes and sea-level changes.