标题:
新疆北部中–晚泥盆世植物稳定碳同位素研究Study on the Stable Carbon Isotope of the Mid-Late Devonian Plants from North Xinjiang
作者:
冯净, 徐洪河, 蒋青
关键字:
有机碳, 泥盆纪, 地球化学, 古气候Organiccarbon, Devonian, Geochemistry, Palaeoclimate
期刊名称:
《Botanical Research》, Vol.3 No.6, 2014-11-24
摘要:
对新疆北部和布克赛尔地区呼吉尔斯特组上段中—晚泥盆世7属9种植物，206个样品开展了植物稳定碳同位素分析，包括草本石松类Haskinsia、Leclercqia，乔木状石松Hoxtolgaya，工蕨类Serrulacaulis，前裸子植物Tetraxylopteris，原始真蕨类Compsocradus，带蕨Taneocrada等，时代跨度从中泥盆世Eifelian期至晚泥盆世Frasnian期。新疆北部泥盆纪陆生植物δ13C值分布范围在−26‰~−19‰之间，与现代C3植物δ13C值分布范围一致。不同类群植物稳定碳同位素组成存在一定的差距，这与植物水分利用效率大小有一定的对应关系。同一植物属种不同器官的δ13C值并不完全相同，δ13C茎轴 > δ13C孢子叶。从Givetian期至Frasnian期，植物δ13C值下降3‰左右，推测与其对应的是CO2浓度的小规模上升，气候变暖。中泥盆世Eifelian期至Givetian期，植物δ13C值并未表现出明显的变化趋势，反映了整个中泥盆世气候可能相对稳定。The stable carbon isotope (δ13C) is analyzed from 206 samples of 7 genera, 9 species of fossil plants from the Upper Member of the Hujiersite Formation, the Hoxtolgay Area, Xinjiang, China, including Haskinsia, Leclercqia, Hoxtolgaya, Serrulacaulis, Tetraxylopteris, Compsocradus, Taneocrada and uncertain roots. The age of these taxa ranges from the early Mid Devonian (Eifelian) to the early Late Devonian (Frasnian). The δ13C value of Devonian plants of North Xinjiang ranges from −26‰ to −19‰, which is similar to that of modern C3 plants. Individual taxon has its own δ13C value range, which is probably a result of different water use efficiency. The δ13C value of different organs of the single plant is not completely same. Normally the δ13C value of the axis is larger than that of sporophyll. From the Givetian to Frasnian, the δ13C value of plants decreases by about 3‰. It is inferred that the decline corresponds to the rise of atmospheric pCO2 and the climate warming. However, the δ13C value of plants rarely changes from Eifelian to Givetian, suggesting the relative stability of the Mid Devonian climate.