Journal
GEOLOGICAL JOURNAL
Volume 56, Issue 3, Pages 1726-1739Publisher
WILEY
DOI: 10.1002/gj.4020
Keywords
clastic dykes; fault‐ induced model; Lower Cretaceous; northern Indian margin; Tethys Himalaya
Categories
Funding
- National Natural Science Foundation of China [41672104, 41888101]
Ask authors/readers for more resources
The study reveals the presence of widespread clastic dyke swarms in the southern Tibetan Himalayas, providing important information on regional depositional processes and tectonic activity. Analysis of the dykes suggests that their formation may be related to tectonic movements and earthquakes.
A clastic dyke is a stratigraphically vertical, wall-like body of clastic material that fills open fissures across strata, and may provide important information on regional depositional processes and tectonic activity. Clastic dyke swarms composed of greyish to brown, fine- to medium-grained lithic-rich volcaniclastic sandstone are widely exposed in the lower Aptian shales in the Gucuo and Wolong areas of the Tethyan Himalaya in southern Tibet, where they are distributed along a series of normal faults. The length and width of clastic dykes range from 5 to 50 m and from 20 to 150 cm, respectively. The U-Pb age spectra of zircon grains contained in clastic dykes are similar to those in Lower Cretaceous sandstones exposed in the studied areas (i.e., Wolong volcaniclastics) and display a youngest peak at 124.3 +/- 2 Ma. Petrographic analyses show that the underlying strata and dykes contain more volcanic lithic fragments and less feldspar grains than the overlying strata, indicating that the dykes were derived from underlying strata and injected upward along faults. Their formation may be explained by a fault-induced clastic-dyke model: normal faults provided conduits for clastic material injected from the underlying unlithified sandstones which were undergoing refluidization owing to over-pressure. We infer that the liquefaction of underlying strata was induced by earthquakes associated with the extensive magmatic activities and regional extension that affected the Indian passive margin of Neotethys during the Early Cretaceous.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available