Determination of Fullerenes (C60/C70) from the Permian-Triassic Boundary in the Meishan Section of South China

Fullerenes (C 60 /C 70 ), clays and rocks near the Permian-Triassic (P/T) boundary in the Meishan section of South China are explored by means of comprehensive analytical techniques, including ultrasonic extraction with column purification, high-performance liquid chromatography (HPLC) and matrix assisted laser desorption/ionization time-of- flight mass spectrometry (MALDI TOF MS). The study confirms the existence of fullerenes toward the P/T event boundary and their absence in clays and limestones beyond the boundary. In particular, the white clay, known as the event boundary, contains fullerenes of 0.33 ppb, while the red material, as the first lamina fill of goethite and gypsum on the base of the white clay, contains fullerenes of 1.23 ppb, and the last lamina of 2.50 ppb. Significantly, distinct enrichment of fullerenes is coincident with the disappearance of fossil records of marine species (94%) just at the base of the white clay, implying that geological fullerenes would be one of temporal remnants led by the P/T catastrophic event. This work strongly supports that fullerenes would be one of significant records of the P/T catastrophic event but their origin remains to be studied further.

Carbon isotope excursions across the Permian-Triassic boundary in the Meishan section, Zhejiang Province, China

Both gradual and sharp decrease in organic and carbonate carbon isotope values were detected across the Permian-Triassic boundary in the Meishan section, Changxing, Zhejiang Province, China. The gradual decrease in organic carbon isotope values started at the bottom of Bed 23, coinciding with the strong oscillations of total organic carbon (TOC) contents, indicates increasing fluxes from carbonate to organic carbon reservoir during this interval. A 2.3‰ sharp drop of inorganic carbon isotope values occurred at the uppermost part of Bed 24e. A 3.7‰ sharp drop of organic carbon isotope values occurred in Bed 26. The dramatic drop of inorganic carbon isotope value of 8‰ reported previously is not confirmed from the unweathered carbonate samples in Bed 27. The large-scale fluctuation of organic carbon isotope values in the Yinkeng Formation reflects different extent of mixing of marine and terrestrial organic matters. The gradual depletion and subsequent sharp drop of carbon isotopes near the

End-Permian catastrophic event of marine acidification by hydrated sulfuric acid:Mineralogical evidence from Meishan Section of South China

The event Permian-Triassic boundary (EPTB) is well marked by the famous 'white clay' of bed 25 in Mei-shan Section located in Changxing county, Zhejiang province of China. In this note, the white clay as well as its overlying and underlying sequences is investigated particularly for mineralogical records. The investigation yields three findings that contribute to better understanding the scenario of the EPTB mass extinction. (i) A red goethite-rich microlayer (0.3 mm) is first recognized to be horizontally widespread on the base of the white clay in the section. The microlayer should be considered as a macro geochemical indicator naturally tracing a catastrophic initiation at the EPTB. (ii) An interruption of marine carbonate deposition is discovered due to blank of carbonate minerals in the white clay. The discovery provides significant evidence of a marine acidification event that would occur in the paleo-ocean with marine acidity estimated at pH【4.0 at least and be triggered by the ultimate

中国煤山剖面二叠/三叠系事件界线地层中石膏的负硫同位素异常

中国煤山剖面二叠系 /三叠系 (P/T)事件界线地层以赋存白粘土和黑粘土著称。本文采用六氟化硫方法经质谱测定发现 ,白粘土中的自形晶石膏、白粘土中的全溶提取石膏和黑粘土中的全溶提取石膏 ,其S同位素均呈显著负值 :δ3 4 SV CDT均值依次为 - 9.2‰、- 10 .7‰和 - 15 .6‰ ;δ3 3 SV CDT均值依次为 - 4 .6‰、- 5 .5‰和 - 8.2‰。P/T事件界线地层中硫酸盐 (石膏 )S同位素如此极端负异常在煤山剖面尚属首次发现 ;在其他P/T剖面乃至在与生物灭绝议题相关的全球其他重要地层界线剖面 ,迄今也未见类似报道。本文还测定出与白粘土密切相关并紧邻的似黄铁矿的铁硫化物 (Fe S) ,其S同位素的δ3 4SV CDT均值为 + 1.3‰和δ3 3 SV CDT均值为 + 0 .7‰ ,且研究中未见任何生物或有机成因黄铁矿痕迹。这在相当大的程度上排除了这里的极轻硫石膏的生物或有机次生来源的可能性。因此 ,本文揭示的显著负硫同位素石膏很可能在自然界中也是罕见的 ,值得进一步积累数据和深入研究。另一方面 ,煤山剖面P/T事件界线层原本富含石膏 ,其极轻硫同位素特征的发现很可能成为一个重要突破口 ,有利于从新的角度认识和探索P/T转折期的灾变与环境变化。

浙江长兴煤山二叠纪末大灭绝化石记录的置信区间分析

化石的保存与采集普遍具有随机性 ,以至直接观察结果往往不能反映真实的生物分类单元延限以及生物事件 ,而必须对化石记录进行统计分析 ,从定量的角度发掘其可信内涵。浙江长兴煤山地区二叠系 三叠系剖面的化石资料经过数十年采集研究 ,已提出多期生物群灭绝模式。文中运用置信区间作了分析 ,说明长兴期末生物大灭绝为突发性。

浙江煤山二叠-三叠系界线剖面有机和无机碳同位素变化与古环境

浙江长兴煤山D剖面196个碳酸盐岩样品无机和有机碳同位素δ13Ccarb和δ13Corg变化趋势表明,煤山地区晚二叠世末为比较封闭的局限海沉积环境,早三叠世初期经局限和开阔海环境交替出现渐变为海水循环良好的广海沉积环境。长兴期的海进作用使海洋初始生产率升高,可能是引起长兴组葆青段碳同位素变重的主要原因;海洋CO2浓度增高可能是长兴组煤山段δ13Corg出现负漂移的原因。二叠纪末期全球性海平面下降以及火山作用可能是使生态系统崩溃、引起二叠-三叠系(P-T)界线附近生物绝灭的外部原因,也是使海洋中12C输入量增加导致过渡层碳同位素变轻的主要原因。二叠纪晚期生物绝灭经历了由渐变到突变的过程。δ13Corg在生物绝灭后才出现大幅度负漂移,可能是由于营光合作用的浮游植物不一定因海洋缺氧以及其他生物的绝灭而停止生长,当海水酸度超过浮游生物忍耐限度时,才导致浮游生物大量死亡。殷坑组δ13Corg和δ13Ccarb呈上升趋势,说明经历过P-T生物大绝灭后,早三叠世海洋生产率逐渐升高,生物开始复苏。

二叠纪-三叠纪野火间断事件对生物灭绝的响应——以浙江煤山剖面为例

二叠纪末期地球气候环境发生重大变化,导致陆地和海洋生态系统崩溃,发生了地质历史上最大规模的生物灭绝事件。大火(亦称野火)作为陆地生态系统的关键影响因子,以及气候环境变化的重要指标,在第四纪以前的历史研究中很少有报道。剖析了煤山二叠纪-三叠纪界线521 ka黑碳和燃烧源多环芳烃的沉积记录,恢复了生物灭绝前后的大火历史。研究显示,生物灭绝前的163 ka内大火频繁,在生物灭绝时则发生了最大规模的大火事件;生物灭绝线以上早三叠世地层中未发现燃烧的记录,出现了大火事件间断(时间持续约358 ka)。对比全球多个剖面,这种大火间断事件可能不是局部现象,而是全球性气候环境变化的响应。陆地植被为大火燃烧的原料,伴随着陆地植被的大规模消失和大气氧含量的快速下降,大火燃烧事件也将消失。因此,煤山剖面二叠纪-三叠纪界线的大火间断能用来指示生物的大规模灭绝事件。