The Rajahmundry Traps, Andhra Pradesh: Evaluation of their petrogenesis relative to the Deccan Traps

Journal of Earth system science

Ajoy K Baksi1¹ 

[1] Department of Geology and Geophysics, Louisiana State University, Baton Rouge, LA 70803, USA.$$

关键词: Flood-basalts;    geochemistry;    age;    plumes;    intracanyon flows;    Rajahmundry;    Deccan.;   

DOI  :  

学科分类：天文学(综合)

来源: Indian Academy of Sciences

【 摘 要 】

Geochemical and geochronological data for rocks from the Rajahmundry Traps, are evaluated for possible correlation with the main Deccan province. Lava flows are found on both banks of the Godavari River and contain an intertrappean sedimentary layer. Based on 40Ar/39Ar age data, rocks on the east bank are post K-T boundary, show normal magnetic polarity, and belong to chron 29N. Their chemistry is identical to lavas in the Mahabaleshwar Formation in the Western Ghats, ∼1000 km away. It was suggested earlier that the genetic link between these geographically widely separated rocks resulted from lava owing down freshly incised river canyons at ∼64 Ma. For the west bank rocks, recent paleomagnetic work indicates lava flows below and above the intertrappean (sedimentary) layer show reversed and normal magnetic polarity, respectively. The chemical composition of the west bank ow above the intertrappean layer is identical to rocks on the east bank. The west bank lava lying below the sedimentary layer, shows chemistry similar to Ambenali Formation lava ows in the western Deccan. 40Ar/39Ar dating and complete chemical characterization of this ow is required to elucidate its petrogenesis with respect to the main Deccan Province.

【 授权许可】

Unknown