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

被引：32

作者：

Baksi A.K. ^{[1
]}

机构：

[1] Department of Geology and Geophysics, Louisiana State University, Baton Rouge

来源：

Journal of Earth System Science | 2001年 / 110卷 / 4期

关键词：

Age; Deccan; Flood-basalts; Geochemistry; Intracanyon flows; Plumes; Rajahmundry;

D O I：

10.1007/BF02702903

中图分类号：

学科分类号：

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 flowing down freshly incised river canyons at ∼64Ma. 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 flow 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 flows in the western Deccan. 40Ar/39Ar dating and complete chemical characterization of this flow is required to elucidate its petrogenesis with respect to the main Deccan Province.

引用

页码：397 / 407

页数：10

共 50 条

[1] Baksi A.K., K-Ar dating: Loading techniques in argon extraction work and sources of air argon contamination, Can. J. Earth Sci, 10, pp. 1678-1684, (1973)
[2] Baksi A.K., Critical evaluation of the age of the Deccan Traps, India: Implications for flood-basalt volcanism and faunal extinctions, Geology, 15, pp. 147-150, (1987)
[3] Baksi A.K., Reevaluation of the timing and duration of extrusion of the Imnaha, Picture Gorge and Grande Ronde Basalts, Columbia river basalt group, Geol. Soc. Am. Spec. Paper, 239, pp. 105-111, (1989)
[4] Baksi A.K., The timing and duration of Mesozoic-Tertiary flood basalt volcanism, Eos, Trans. Am. Geophys. Union, 71, pp. 1835-1840, (1990)
[5] Baksi A.K., Geochronological studies on whole-rock basalts, Deccan Traps, India: Evaluation of the timing of volcanism relative to the K-T boundary, Earth Planet. Sci. Lett, 121, pp. 43-56, (1994)
[6] Baksi A.K., Reevaluation of plate motion models based on hotspot tracks in the Atlantic and Indian Oceans, J. Geol, 107, pp. 13-26, (1999)
[7] Baksi A.K., Search for a deep mantle component in mafic lavas using a Nb - Y - Zr plot, Can. J. Earth Sci, 38, pp. 813-824, (2001)
[8] Baksi A.K., Archibald D.A., Mesozoic igneous activity in the Maranhao province, Northern Brazil: 40Ar/39Ar evidence for separate episodes of basaltic magmatism, Earth Planet. Sci. Lett, 151, pp. 139-153, (1997)
[9] Baksi A.K., Archibald D.A., Farrar E., Intercalibration of 40Ar/39Ar dating standards, Chem. Geol, 129, pp. 307-324, (1996)
[10] Baksi A.K., Hsu V., McWilliams M.O., Farrar E., 40Ar/39Ar dating of the Brunhes/Matuyama geomagnetic reversal, Science, 256, pp. 356-357, (1992)

← 1 2 3 4 5 →