TY - JOUR
T1 - A meta-analysis of the Steptoean Positive Carbon Isotope Excursion
T2 - The SPICEraq database
AU - Pulsipher, Mikaela A.
AU - Schiffbauer, James D.
AU - Jeffrey, Matthew J.
AU - Huntley, John Warren
AU - Fike, David A.
AU - Shelton, Kevin L.
N1 - Funding Information:
The authors would like to thank P. Scheel and the staff at the McCracken Core Library and Research Center, Missouri Department of Natural Resources for core access and assistance, S. Jacquet (Univ. of Missouri) for sample collection assistance, S. Moore (Washington Univ. in St. Louis) for IRMS processing, and S. Rosbach (Univ. of Missouri) for RStudio assistance. We additionally thank M. Brown, M. Chisholm, V. Beckham, E. Bunton, and G. Halliwell for project inspiration. Funding: This work was supported by the Univ. of Missouri Research Council to KLS; the Univ. of Missouri Dept. of Geological Sciences to MAP [James H. Stitt Memorial Fellowship, Keller Opportunities for Excellence, and Marshall Opportunities for Excellence]; the National Science Foundation to JDS [ EAR CAREER #1652351 ] and JWH [ EAR CAREER #1650745 ].
Publisher Copyright:
© 2020 Elsevier B.V.
PY - 2021/1
Y1 - 2021/1
N2 - The Steptoean Positive Isotopic Carbon Excursion (SPICE) is a prominent chemostratigraphic feature in the Lower Paleozoic. It has been used to correlate Upper Cambrian carbonate strata globally, and is cited as intimately linked to the Crepicephalus-Aphelaspis trilobite extinction event and the Sauk II-Sauk III megasequence transition. Despite the global nature of the SPICE event, regional/local conditions serve as a control on the expression of the SPICE event in the rock record. In light of this, and to better understand how reliable the SPICE event is as a chemostratigraphic tool for correlation, we have created the “SPICEraq,” a database comprising 78 SPICE-bearing sections containing 6669 individual δ13C analyses. In this study, we quantitatively evaluate the variability in SPICE records, and document that, while the excursion is a global signature, its stratigraphic expression is influenced by such conditions as paleolatitude, paleocontinent, water depth, and facies. While the magnitude of the SPICE excursion is generally consistent (an ~4‰ increase), the peak δ13C values are quite variable (ranging from +0.35 to +5.87‰). Specifically, sections located between 30 and 60°S paleolatitude ca. 500 Ma record δ13C values ~1 to 2‰ lower than those from lower paleolatitudes. Sections deposited in shallow water depths and facies also record lower δ13C values than intermediate and deep-water facies; the deep-water facies exhibit the most 13C-enriched carbonates at the peak of the SPICE and post-excursion. The stratigraphic thickness of the excursion varies widely, ranging from <3 to ~884 m, and is significantly impacted by all categorical variables investigated in this study. This study documents that the rising limb of the SPICE is immediately preceded by a small negative δ13C excursion in 75% of sections with data collected pre-SPICE. While 32% of sections record a δ13C plateau during peak SPICE, its presence in the δ13C record does not appear to be influenced by any environmental conditions investigated herein. Altogether, these analyses indicate that regional/local conditions impact the stratigraphic expression of δ13C records, and thus care should be taken to use robust, quantitative measures to compare and correlate excursions.
AB - The Steptoean Positive Isotopic Carbon Excursion (SPICE) is a prominent chemostratigraphic feature in the Lower Paleozoic. It has been used to correlate Upper Cambrian carbonate strata globally, and is cited as intimately linked to the Crepicephalus-Aphelaspis trilobite extinction event and the Sauk II-Sauk III megasequence transition. Despite the global nature of the SPICE event, regional/local conditions serve as a control on the expression of the SPICE event in the rock record. In light of this, and to better understand how reliable the SPICE event is as a chemostratigraphic tool for correlation, we have created the “SPICEraq,” a database comprising 78 SPICE-bearing sections containing 6669 individual δ13C analyses. In this study, we quantitatively evaluate the variability in SPICE records, and document that, while the excursion is a global signature, its stratigraphic expression is influenced by such conditions as paleolatitude, paleocontinent, water depth, and facies. While the magnitude of the SPICE excursion is generally consistent (an ~4‰ increase), the peak δ13C values are quite variable (ranging from +0.35 to +5.87‰). Specifically, sections located between 30 and 60°S paleolatitude ca. 500 Ma record δ13C values ~1 to 2‰ lower than those from lower paleolatitudes. Sections deposited in shallow water depths and facies also record lower δ13C values than intermediate and deep-water facies; the deep-water facies exhibit the most 13C-enriched carbonates at the peak of the SPICE and post-excursion. The stratigraphic thickness of the excursion varies widely, ranging from <3 to ~884 m, and is significantly impacted by all categorical variables investigated in this study. This study documents that the rising limb of the SPICE is immediately preceded by a small negative δ13C excursion in 75% of sections with data collected pre-SPICE. While 32% of sections record a δ13C plateau during peak SPICE, its presence in the δ13C record does not appear to be influenced by any environmental conditions investigated herein. Altogether, these analyses indicate that regional/local conditions impact the stratigraphic expression of δ13C records, and thus care should be taken to use robust, quantitative measures to compare and correlate excursions.
KW - Cambrian Period
KW - Chemostratigraphy
KW - Furongian Series
KW - Isotope geochemistry
KW - Paibian Stage
KW - Steptoean Positive Carbon Isotope Excursion
UR - http://www.scopus.com/inward/record.url?scp=85097241621&partnerID=8YFLogxK
U2 - 10.1016/j.earscirev.2020.103442
DO - 10.1016/j.earscirev.2020.103442
M3 - Review article
AN - SCOPUS:85097241621
SN - 0012-8252
VL - 212
JO - Earth-Science Reviews
JF - Earth-Science Reviews
M1 - 103442
ER -