Palynostratigraphy of the subsurface sediments of Upper Assam Basin, India

Citation
M. Kumar et al., Palynostratigraphy of the subsurface sediments of Upper Assam Basin, India, GEOBIOS, 34(3), 2001, pp. 241-251
Citations number
35
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Earth Sciences
Journal title
GEOBIOS
ISSN journal
0016-6995 → ACNP
Volume
34
Issue
3
Year of publication
2001
Pages
241 - 251
Database
ISI
SICI code
0016-6995(2001)34:3<241:POTSSO>2.0.ZU;2-B
Abstract
The palynoflora and palynodebris content have been studied of a 3800 in dee p well situated in the oil producing Tinali area in the Upper Assam basin o f the Brahmaputra Valley, India. The well penetrated through Dhekiajuli For mation, Namsang Formation, Tipam, Surma and Barail Groups (Oligocene-Pleist ocene). Microfloral change from Barail Group to Surma Group is distinct and indicates a more rich deltaic swamp vegetation during deposition of Barail Group than overlying sediments. The fluviatile Neogene sediments are poor in microfossils and indicative of comparatively drier conditions. Three inf ormal zones have been proposed based on occurrance or abundance of palynofo ssils. Amorphous organic matter is dominant in the Barail Group and is grad ually replaced by biodegraded terrestrial and black debris in the post-Bara il sediments. Reworked Palaeozoic and Mesozoic palynofossils occur through out the sequence. Moreover, reworked Palaeocene and Eocene palynotaxa are a lso recovered from the post-Barail sediments. This phenomenon is related wi th the Himalayan orogenic movements. (C) Editions scientifiques et medicale s Elsevier SAS.