Publication Date:
2023-07-10
Description:
The chronostratigraphy of Guandao section has served as the foundation for numerous studies of the end-Permian extinction and biotic recovery in south China. Guandao section is continuous from the Permian-Triassic boundary to the Upper Triassic.
Conodonts enable broad delineation of stage and substage boundaries and calibration of foraminifer biostratigraphy as follows. Changhsingian-Griesbachian: first Hindeodus parvus, and first appearance of foraminifers Postcladella kalhori and Earlandia sp. Griesbachian-Dienerian: first Neospathodus dieneri, and last appearance of foraminifer P. grandis. Dienerian-Smithian: first Novispathodus waageni and late Dienerian first appearance of foraminifer Hoyenella ex gr. sinensis. Smithian-Spathian: first Nv? crassatus and last appearance of foraminifers Arenovidalina n. sp. and Glomospirella cf. vulgaris. Spathian-Aegean: first Chiosella timorensis and first appearance of foraminifer Meandrospira dinarica. Aegean-Bithynian: first Nicoraella germanica and first appearance of foraminifer Pilammina densa. Bithynian-Pelsonian: after last Neogondolella regalis, prior to first Paragondolella bulgarica and first appearance of foraminifer Aulotortus eotriasicus. Pelsonian-Illyrian: first Pg. excelsa and last appearance of foraminifers Meandrospira? deformata and Pilamminella grandis. Illyrian-Fassanian: first Budurovignathus truempyi, and first appearance of foraminifers Abriolina mediterranea and Paleolituonella meridionalis. Fassanian-Longobardian: first Bv. mungoensis and last appearance of foraminifer A. mediterranea. Longobardian-Cordevolian: first Quadralella polygnathiformis and last appearance of foraminifers Turriglomina mesotriasica and Endotriadella wirzi.
The section contains primary magnetic signature with frequent reversals occurring around the Permian-Triassic, Olenekian-Anisian, and Anisian-Ladinian boundaries. Predominantly normal polarity occurs in the lower Smithian, Bithynian, and Longobardian-Cordevolian. Predominantly reversed polarity occurs in the upper Griesbachian, Induan-Olenekian, Pelsonian and lower Illyrian. Reversals match well with the GPTS. Large amplitude carbon isotope excursions, attaining values as low as -2.9 per mil d13C and high as +5.7 per mil d13C, characterize the Lower Triassic and basal Anisian. Values stabilize around +2 per mil d13C through the Anisian to Carnian. Similar signatures have been reported globally. Magnetic susceptibility and synthetic gamma ray logs show large fluctuations in the Lower Triassic and an overall decline in magnitude of fluctuation through the Middle and Upper Triassic. The largest spikes in magnetic susceptibility and gamma ray, indicating greater terrestrial lithogenic flux, correspond to positive d13C excursions. High precision U-Pb analysis of zircons from volcanic ash beds provide a robust age of 247.28 ± 0.12 Ma for the Olenekian-Anisian boundary at Guandao and an age of 251.985 ± 0.097 Ma for the Permian-Triassic boundary at Taiping. Together, the new U-Pb geochronology from the Guandao and Taiping sections suggest an estimated duration of 4.71 ± 0.15 Ma for the Early Triassic Epoch.
Keywords:
Abriolina mediterranea; Agathammina sp.; Age, dated; Age, dated standard error; Age, Uranium-Lead; Arenovidalina sp.; Aulotortus eotriasicus; Austrocolomia marschalli; Bianyang, Guizhou, China; Budurovignathus hungaricus; Budurovignathus mungoensis; Budurovignathus truempyi; Chemical Gamma Ray; Chiosella gondolelloides; Chiosella timorensis; Clarkina changxingensis; Conservatella conservativa; Cornudina sp.; Cratognathus spp; Discretella discreta; Endoteba bithynica; Endoteba controversa; Endotebanella kocaeliensis; Endotebanella sp.; Endoteba obturata; Endotriada thyrrhenica; Endotriadella wirzi; Eurygnathodus sp.; Foraminifera, benthic indeterminata; Galeanella sp.; Gladigondolella carinata; Gladigondolella tethydis; Glomospirella cf. vulgaris; Guandao_Section; Guangxidella bransoni; HAND; Hindeodus anterodentatus; Hindeodus parvus; Hindeodus typicalis; Hoyenella ex gr. sinensis; Inductively coupled plasma - mass spectrometry (ICP-MS); Krikoumbilica pileiformis; Light microscope; Magnetic susceptibility; Magnetometer, cryogenic, 2G-755R, thermal demagnetization; Malayspirina sp.; Mass spectrometer Finnigan MAT 252; Meandrospira cheni; Meandrospira deformata; Meandrospira dinarica; Meandrospira pusilla; Meandrospira sp.; Meandrospirillina irregularis; Mosherella newpassensis; Neogondolella bifurcata; Neogondolella constricta; Neogondolellaregalis; Neogondolella trammeri; Neogondolella transita; Neospathodus crassatus; Neospathodus cristagalli; Neospathodus dieneri; Neospathodus pakistanensis; Neospathodus peculiaris; Neospathodus triangularis; Neostrachanognathus spp.; Nicoraella germanica; Nicoraella kockeli; Nicoraella sp.; Novispathodus abruptus; Novispathodus waageni; Ophthalmidium exiguum; Ophthalmidium spp.; Paleolituonella meridionalis; Paleolituonella reclinata; Paragondolella alpina; Paragondolella bifurcata; Paragondolella bulgarica; Paragondolella excelsa; Paragondolella foliata; Paragondolella fuelopi; Paragondolella inclinata; Piallina bronnimanni; Pilammina densa; Pilamminella grandi; Planiinvoluta mesotriasica; Quadralella polygnathiformis; Quadralella tadpole; Sample code/label; Sampling by hand; SECTION, height; Spathicuspus spathi; Susceptibility bridge; Tolypammina gregaria; Triadodiscus sp.; Triassospathodus brochus; Triassospathodus homeri; Triassospathodus symmetricus; Trochammina almtalensis; Turriglomina carnica; Turriglomina cf. magna; Turriglomina mesotriasica; Turrispirillina sp.; Virtual geomagnetic pole latitude; δ13C, carbonate
Type:
Dataset
Format:
text/tab-separated-values, 93579 data points
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