Palynoflora from deccan volcano-sedimentary sequence (Cretaceous-Palaeogene transition) of central India: implications for spatio-temporal correlation
Palynoflora from deccan volcano-sedimentary sequence (Cretaceous-Palaeogene transition) of central India: implications for spatio-temporal correlation
复制标题
印度中部德干火山沉积序列（白垩纪-古近纪过渡）的孢粉植物群：对时空相关性的影响
作者：
B. Samant;D. Mohabey
对中央邦 Jabalpur-Mandla-Chhindwara (JMC) 地区火山省和 Nand-Dongargaon (N-D) 盆地以及马哈拉施特拉邦 Yeotmal-Nanded 西部毗邻地区暴露的德干大陆溢流玄武岩 (DCFB) 序列相关的沉积层进行了孢粉花分析。对沉积物进行了孢粉学表征，并在许多剖面的不同地层水平上观察到孢粉植物区系的变化，包括近年来记录的几个新的陷阱间地点。为了有效关联不同亚省，还对一些先前研究的夹层植物的孢粉植物区系进行了回顾。我们的研究表明，在德干火山活动开始之前，拉梅塔沉积物中发现的孢粉植物群以裸子植物-被子植物群落为主。植物冠层主要由裸子植物（针叶树和罗汉松科）组成，而林下成员主要由棕榈科和草本植物（禾本科和菊科）组成。德干火山流的喷发严重影响了现有的花卉协会，并被证明对成熟的植物群落是致命的。与最早的火山流相关的直接上覆沉积物主要是蕨类植物和被子植物类群（Azolla cretacea、Aquilapollenites bengalensis、Ariadnaesporites sp.、Gabonisporis vigourouxii 和 Triporoletes reticulatus）。在地层序列的较高部分，类似的形式继续存在，同时出现了新的类群，包括 Scabrastephanocolpites spp。在更高的地层水平上，观察到真菌特别是菌根真菌的丰度，同时花粉/孢子恢复率急剧下降。在德干火山历史的顶峰阶段（即古新世），遇到了典型古新世类群（Dandotiaspora dilata、D.pseudoauriculata、D.plicata、Spinizonocolpites echinatus、Matanomadhiasulcites sp.和Lakiapollis ovatus）的新孢粉植物组合。
The sedimentary beds associated with Deccan Continental Flood Basalt (DCFB) sequences exposed in the volcanic subprovinces of Jabalpur-Mandla-Chhindwara (JMC) regions of Madhya Pradesh and Nand-Dongargaon (N-D) basin and the adjoining areas to the west in Yeotmal-Nanded in Maharashtra were studied for their palynofloral analysis. The sediments were characterized palynologically and changes in the palynoflora are observed at different stratigraphic levels in a number of sections including several new intertrappean localities recorded in recent years. For the purpose of effective correlation of different subprovinces, palynofloras of some of the previously studied intertrappeans are also reviewed. Our studies suggest that before the start of the Deccan volcanic activity, the palynoflora found in the Lameta sediments, was dominated by gymnosperms-angiosperm association. The plant canopy consisted mainly of gymnosperms (Conifers and Podocarpaceae) whereas, the understory members were mostly of palms and herbs (Poaceae and Asteraceae). The eruption of Deccan volcanic flows severely affected the existing floral association and proved fatal for the well established plant community. The immediately overlying sediments associated with the earliest volcanic flows are dominated by pteridophytes and angiosperm taxa (Azolla cretacea, Aquilapollenites bengalensis, Ariadnaesporites sp., Gabonisporis vigourouxii and Triporoletes reticulatus). Higher up in the stratigraphic sequence, similar forms continued with simultaneous appearance of new taxa including Scabrastephanocolpites spp. At still higher stratigraphic levels, abundance of fungi especially the mycorrhizal fungi, concurrent with sharp decline in pollen/spore recovery was observed. In the culminating phase (i.e. Palaeocene) of Deccan volcanic history a new palynofloral assemblage of typical Palaeocene taxa (Dandotiaspora dilata, D. pseudoauriculata, D. plicata, Spinizonocolpites echinatus, Matanomadhiasulcites sp., and Lakiapollis ovatus) was encountered.