T211 Geochemical Approaches to Sedimentary Provenance Studies II

Tuesday, 20 October 2009
1:30 PM - 5:30 PM
Portland Ballroom 252

207Pb/206Pb SHRIMP AGES OF DETRITAL ZIRCONS IN THE MESOPROTEROZOIC CHHATTISGARH BASIN, CENTRAL INDIA, AID IN IDENTIFYING RELATIVE LOW-STAND AND HIGH-STAND SANDSTONES

Paper number: T211-10
Program: Technical Sessions
Time: 3:40 PM – 3:55 PM

Authors

Abstract

We argue that the detritus deposited during relative low-stand and above an erosional unconformity would likely be derived from a variety of source rocks beyond the basin and reworked intrabasinal sediments. In contrast, the detritus deposited during relative high-stand would likely be derived only from major source rocks beyond the basin. Zircon and quartz, being by far the two most durable minerals, would retain this contrasting provenance information. Our recent 207Pb/206Pb age-data of detrital zircons in the Chhattisgarh Basin bear us out. The table below shows that the Sarnadih Sandstone above Unconformity 3 received detritus not only from the basement granite, but also from the Singhora and the Sukhda Tuff. In contrast, the Kansapathar Sst had only one dominant source. We infer that Sarnadih and Kansapathar sands were deposited during relative low- and high-stands respectively. This provenance analysis predicts that the Gomarda Sandstone (above Unconformity 1) should contain some reworked zircons from the Singhora Tuff in addition to basement detritus.

Table. Relevant Units and Detrital Zircon Ages in the Stratigraphic Column

Shale-dolomite-evaporite

Sarnadih Sst; lithic (1007, 1183, 1303, 1494, 1585, 1727, 1931, 2461, 2539, 2660 Ma)

~~~~~~~~ Erosional Unconformity 3 ~~~~~~~~~~~~~

Sukhda Tuff (990-1020; 1178, 1367, 1459, 1593, 2560 Ma)

Carbonate-Shale rocks

~~~~~~~~~~ Unconformity 2 ~~~~~~~~~~~~~~~~~~~

Kansapathar Sst; quartz arenite (2484 Ma)

Gomarda/Chaporadih Sst; quartz arenite (NO age data yet)

~~~~~~~~ Erosional Unconformity 1 ~~~~~~~~~~~~~

Singhora Tuff (1405, 1510, 1800, 2250, 2340, 2400, 2450, 2490, 2600 Ma)

Rehatikhol Sst; arkose (2270, 2472 Ma)

Rehatikhol Sst; conglomeratic arkose (2460 Ma)

~~~~~~~~ Erosional Unconformity 0 ~~~~~~~~~~~~~~

Basement granite (~2380-2480 Ma); older gneiss (~2528-2636 Ma); younger greenstone