Mathematics – Logic
Scientific paper
Nov 2008
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2008m%26ps...43.1383p&link_type=abstract
Meteoritics & Planetary Science, vol. 43, Issue 8, p.1383-1398
Mathematics
Logic
4
Dhala, Impact Structure, Shock Metamorphism, Paleoproterozoic
Scientific paper
The newly discovered Dhala structure, Madhya Pradesh State, India, is the eroded remnant of an impact structure with an estimated present-day apparent diameter of about 11 km. It is located in the northwestern part of the Archean Bundelkhand craton. The pre-impact country rocks are predominantly granitoids of ˜2.5 Ga age, with minor 2.0 2.15 Ga mafic intrusive rocks, and they are overlain by post-impact sediments of the presumably ?1.7 Ga Vindhyan Supergroup. Thus, the age for this impact event is currently bracketed by these two sequences. The Dhala structure is asymmetrically disposed with respect to a central elevated area (CEA) of Vindhyan sediments. The CEA is surrounded by two prominent morphological rings comprising pre-Vindhyan arenaceousargillaceous and partially rudaceous metasediments and monomict granitoid breccia, respectively. There are also scattered outcrops of impact melt breccia exposed towards the inner edge of the monomict breccia zone, occurring over a nearly 6 km long trend and with a maximum outcrop width of ˜170 m. Many lithic and mineral clasts within the melt breccia exhibit diagnostic shock metamorphic features, including multiple sets of planar deformation features (PDFs) in quartz and feldspar, ballen-textured quartz, occurrences of coesite, and feldspar with checkerboard texture. In addition, various thermal alteration textures have been found in clasts of initially superheated impact melt. The impact melt breccia also contains numerous fragments composed of partially devitrified impact melt that is mixed with unshocked as well as shock deformed quartz and feldspar clasts. The chemical compositions of the impact melt rock and the regionally occurring granitoids are similar. The Ir contents of various impact melt breccia samples are close to the detection limit (1 1.5 ppb) and do not provide evidence for the presence of a meteoritic component in the melt breccia. The presence of diagnostic shock features in mineral and lithic clasts in impact melt breccia confirm Dhala as an impact structure. At 11 km, Dhala is the largest impact structure currently known in the region between the Mediterranean and southeast Asia.
Koeberl Christian
Pati Jayanta K.
Pati Puniti
Reimold Wolf Uwe
No associations
LandOfFree
The Dhala structure, Bundelkhand craton, Central India—Eroded remnant of a large Paleoproterozoic impact structure. does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with The Dhala structure, Bundelkhand craton, Central India—Eroded remnant of a large Paleoproterozoic impact structure., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and The Dhala structure, Bundelkhand craton, Central India—Eroded remnant of a large Paleoproterozoic impact structure. will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-750824