This study provides a combined analysis on the palynology, fossil charcoal and biomarkers of the subsurface coal deposits from a borehole RMB #2 drilled at the Dhulia Coal Block, Rajmahal Basin, India, in attempts to establish the chronology of sedimentation and to propose palaeobotanical as well as geochemical evidence for the occurrence of wildfires in these sediments. The palynological investigation suggests a Scheuringipollenites barakarensis palynoassemblage from the lower Barakar Formation, dated as Artinskian (Early Permian) in age. This assemblage reveals the dominance of Glossopteridales and sub-dominance of taxa belonging to Cordaitales and Coniferales. Fossil charcoal in sediments is usually recognized as a direct indicator for the occurrence of palaeo-wildfires. More data involving the anatomical features of fossil charcoal analyzed by Field Emission Scanning Electronic Microscope broaden our knowledge on Early Permian wildfires from the peninsula of India. The studied macroscopic charcoal fragments exhibit anatomical details such as homogenized cell walls, uniseriate simple and biseriate alternate pitting on tracheid walls and rays of varying heights pointing to a gymnospermous wood affinitity. The excellent preservation of charcoal fragments, shown by their large sizes and almost unabraded edges, suggests a parautochthonous origin. The embedded biomarker study performed for charcoal sediments and its characterization demonstrate the presence of n-alkanes, isoprenoids, terpenoids and aromatic compounds. A bimodal distribution pattern of n-alkanes with a Cmax at n-C25 is identified. Diterpenoids and pentacyclic terpenoids are identified, indicating the input of an early conifer vegetation and bacterial activity, respectively. The identified polyaromatic hydrocarbon (PAH) compounds, together with the charcoal fragments, clearly suggest that repeated wildfire events occurred during the deposition of these Artinskian sediments in the Rajmahal Basin.

中文翻译：

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印度拉杰马哈尔盆地早二叠世（Artinskian）野火的古植物和生物标志物证据

这项研究提供了对印度拉贾马哈盆地杜利亚煤炭区块钻探的＃2井下地下煤层的孢粉学，化石炭和生物标志物的综合分析，以试图建立沉积年代学并提出古植物学以及这些沉积物中发生野火的地球化学证据。孢粉学研究表明，来自下巴拉卡尔组的Scheuringipollenites barakarensis palyno组合，年龄为Artinskian（早二叠世）。这种组合揭示了鞘翅目的优势和属于Cordaitales和Coniferales的分类单元的主要优势。沉积物中的化石木炭通常被认为是古野火发生的直接指示。通过场发射扫描电子显微镜分析的涉及化石炭的解剖特征的更多数据，拓宽了我们对印度半岛早期二叠纪野火的了解。所研究的宏观木炭碎片表现出解剖学细节，例如均质的细胞壁，气管壁上单一的，简单的和双反面的交替凹坑以及指向裸子植物木材亲和力的不同高度的射线。木炭碎片的大尺寸和几乎未磨损的边缘显示出对木炭碎片的极佳保存，表明其为准真人起源。对木炭沉积物进行的嵌入式生物标志物研究及其表征证明了正构烷烃，类异戊二烯，萜类化合物和芳香族化合物的存在。鉴定了在n-C25处具有Cmax的正构烷烃的双峰分布模式。确定了二萜和五环萜类化合物，分别指示了早期针叶树植被和细菌活性的输入。鉴定出的多环芳烃（PAH）化合物以及木炭碎片清楚地表明，在拉贾马哈尔盆地这些Artinskian沉积物的沉积过程中反复发生野火事件。