TY - JOUR

T1 - The Xiaoyangqiao section, Dayangcha, North China

T2 - the new global Auxiliary Boundary Stratotype Section and Point (ASSP) for the base of the Ordovician System

AU - Wang, Xiaofeng

AU - Stouge, Svend

AU - Maletz, Jörg

AU - Bagnoli, Gabriella

AU - Qi, Yuping

AU - Raevskaya, Elena G.

AU - Wang, Chuanshang

AU - Yan, Chunbo

PY - 2021

Y1 - 2021

N2 - In 2019 the Sub-Commission on the Ordovician System approved the Xiaoyangqiao section, North China as a new ASSP section for the base of the Ordovician System. The sedimentary succession of the section is exposed in a natural outcrop near the Dayangcha Village at a position of 42 degrees 3'24 '' N, 126 degrees 42'21 '' E. It has a well-preserved, abun-dant and diverse fossil record across the boundary with key markers (conodonts and graptolites), which provide improved intercontinental correlation of the Cambrian- Ordovician boundary. The appearance of the first plank -tonic graptolites is immediately below the base of the Cordy-lodus lindstromi Conodont Zone. Other fossils, including acritarchs, brachiopods and trilobites are also present in the Xiaoyangqiao ASSP section. Non-biotic secondary global markers near the base of the Ordovician System include a positive carbon isotopic excursion with the maximum peak (named HSS) below the boundary, a prominent unnamed negative peak immediately below the boundary and a prominent carbon isotope excursion with positive peaks above the boundary. The latter excursion is associated with the appearance of the planktonic graptolites in the Ordo-vician. The strength of the Xiaoyangqiao ASSP section is the correlation between the conodonts and graptolites, correspondence of sea-level lowstands, and the matches of geochemical parameters.

AB - In 2019 the Sub-Commission on the Ordovician System approved the Xiaoyangqiao section, North China as a new ASSP section for the base of the Ordovician System. The sedimentary succession of the section is exposed in a natural outcrop near the Dayangcha Village at a position of 42 degrees 3'24 '' N, 126 degrees 42'21 '' E. It has a well-preserved, abun-dant and diverse fossil record across the boundary with key markers (conodonts and graptolites), which provide improved intercontinental correlation of the Cambrian- Ordovician boundary. The appearance of the first plank -tonic graptolites is immediately below the base of the Cordy-lodus lindstromi Conodont Zone. Other fossils, including acritarchs, brachiopods and trilobites are also present in the Xiaoyangqiao ASSP section. Non-biotic secondary global markers near the base of the Ordovician System include a positive carbon isotopic excursion with the maximum peak (named HSS) below the boundary, a prominent unnamed negative peak immediately below the boundary and a prominent carbon isotope excursion with positive peaks above the boundary. The latter excursion is associated with the appearance of the planktonic graptolites in the Ordo-vician. The strength of the Xiaoyangqiao ASSP section is the correlation between the conodonts and graptolites, correspondence of sea-level lowstands, and the matches of geochemical parameters.

KW - CONODONT IAPETOGNATHUS

KW - JILIN-PROVINCE

KW - GREEN POINT

KW - SEA-LEVEL

KW - STRATIGRAPHY

KW - NEWFOUNDLAND

KW - GSSP

KW - GRAPTOLITE

KW - EVOLUTION

KW - TRILOBITE

U2 - 10.18814/epiiugs/2020/020091

DO - 10.18814/epiiugs/2020/020091

M3 - Journal article

VL - 44

SP - 359

EP - 383

JO - Episodes

JF - Episodes

SN - 0705-3797

IS - 4

ER -