A Late Cambrian positive carbon-isotope excursion in the Southern Appalachians; relation to biostratigraphy, sequence stratigraphy, environments of deposition, and diagenesis

1998 ◽  
Vol 68 (6) ◽  
pp. 1212-1222 ◽  
Author(s):  
B. Glumac ◽  
K. R. Walker
Keyword(s):  
Sequence Stratigraphy ◽  
Carbon Isotope ◽  
Southern Appalachians ◽  
Late Cambrian ◽  
Carbon Isotope Excursion

The geochemistry of the late Cambrian carbonate in North China: the Steptoean Positive Carbon Isotope Excursion (SPICE) record suppressed in a coastal condition?

2019 ◽  
Vol 156 (10) ◽  
pp. 1805-1819 ◽  
Author(s):  
Jing Huang ◽  
Yali Chen ◽  
Xuelei Chu ◽  
Tao Sun
Keyword(s):  
Sea Level ◽  
Carbon Isotope ◽  
North China ◽  
Coastal Environment ◽  
Sedimentary Records ◽  
Late Cambrian ◽  
Geochemical Proxies ◽  
Carbon Isotope Excursion ◽  
Globally Distributed ◽  
Shallow Coastal Environment

AbstractThe Steptoean Positive Carbon Isotope Excursion (SPICE) is globally distributed in late Cambrian sedimentary records but controversially heterogeneous in its magnitudes. Here we use multiple geochemical proxies to investigate the late Cambrian carbonates from the Tangwangzhai section in North China, which were deposited in a shallow coastal environment with three depositional sequences (S1–S3). Each sequence comprises a transgressive systems tract (TST) and a highstand systems tract (HST). The REE + Y and trace element records are consistent with the depositional condition and indicate that terrigenous influence was more significant in the TST than HST. δ13Ccarb and δ34SCAS are low in the TST relative to HST, consistent with the scenario that terrigenous inputs were profoundly aggressive to seawater by introducing 13C-depleted and 34S-depleted materials. Within the TST of S2, the SPICE excursion shows a scaled-down δ13Ccarb positive shift (∼1.7 ‰) relative to its general records (∼4–6 ‰); the corresponding δ34SCAS show no positive excursion. This ‘atypical’ SPICE record is attributed to enhanced 13C-depleted and 34S-depleted terrigenous influence during the TST, which would reduce the amplitude of δ13Ccarb excursion, and even obscure δ34SCAS excursion. Meanwhile the subaerial unconformity at the base of TST would also cause a partially missing and a ‘snapshot’ preservation. Our study confirms significant local influence to the SPICE records, and further supports the heterogeneity and low sulphate concentrations of the late Cambrian seawater, because of which the SPICE records may be vulnerable to specific depositional conditions (e.g. sea-level, terrigenous input).

scholarly journals The Furongian (late Cambrian) Steptoean Positive Carbon Isotope Excursion (SPICE) in Avalonia

2011 ◽  
Vol 168 (4) ◽  
pp. 851-862 ◽  
Author(s):  
Mark A. Woods ◽  
Philip R. Wilby ◽  
Melanie J. Leng ◽  
Adrian W.A. Rushton ◽  
Mark Williams
Keyword(s):  
Carbon Isotope ◽  
Late Cambrian ◽  
Carbon Isotope Excursion

scholarly journals Sequence stratigraphy, chemostratigraphy and facies analysis of Cambrian Series 2 – Series 3 boundary strata in northwestern Scotland

2016 ◽  
Vol 155 (4) ◽  
pp. 865-877 ◽  
Author(s):  
LUKE E. FAGGETTER ◽  
PAUL B. WIGNALL ◽  
SARA B. PRUSS ◽  
YADONG SUN ◽  
ROBERT J. RAINE ◽  
...  
Keyword(s):  
Sea Level ◽  
Sequence Stratigraphy ◽  
Carbon Isotope ◽  
Sea Level Changes ◽  
Carbon Isotopic ◽  
Carbonate Carbon ◽  
Carbon Isotope Excursion ◽  
Isotope Record ◽  
Laurentian Margin ◽  
Sequence Boundaries

AbstractGlobally, the Series 2 – Series 3 boundary of the Cambrian System coincides with a major carbon isotope excursion, sea-level changes and trilobite extinctions. Here we examine the sedimentology, sequence stratigraphy and carbon isotope record of this interval in the Cambrian strata (Durness Group) of NW Scotland. Carbonate carbon isotope data from the lower part of the Durness Group (Ghrudaidh Formation) show that the shallow-marine, Laurentian margin carbonates record two linked sea-level and carbon isotopic events. Whilst the carbon isotope excursions are not as pronounced as those expressed elsewhere, correlation with global records (Sauk I – Sauk II boundary andOlenellusbiostratigraphic constraint) identifies them as representing the local expression of the ROECE and DICE. The upper part of the ROECE is recorded in the basal Ghrudaidh Formation whilst the DICE is seen around 30m above the base of this unit. Both carbon isotope excursions co-occur with surfaces interpreted to record regressive–transgressive events that produced amalgamated sequence boundaries and ravinement/flooding surfaces overlain by conglomerates of reworked intraclasts. The ROECE has been linked with redlichiid and olenellid trilobite extinctions, but in NW Scotland,Olenellusis found after the negative peak of the carbon isotope excursion but before sequence boundary formation.

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