Dimmitt, H3.5-3.7

Dimmitt is one of the largest meteorites known from North America; hundreds of kilograms of fragments and individuals have been recovered from the plains around Dimmitt, Texas.  The meteorite is an unequillibrated, gas-bearing regolith breccia — the churned-up surface of an asteroid.  Most of Dimmitt is composed of ~fairly primitive material, but some very pristine xenoliths have also been found worked into the rock.

Strangely, the largest single stones recovered from the fall have weighed less than ~ten kilograms, though I think this may be because larger stones buried themselves deeply upon impact, below the reach of farmers’ plows.

Here are a few papers that looked at Dimmit and found some interesting things:

Nature of the H chondrite parent body regolith: Evidence from the Dimmitt breccia, by A.E. Rubin, E.R.D. Scott, G.J. Taylor, K. Keil, J.S.B. Allen, T.K. Mayeda, R.N. Clayton, and D.D. Bogard (1983)

Structure and fragmentation of the parent asteroids of ordinary chondrites, by G.J. Taylor, E.R.D. Scott, A.E. Rubin, P. Maggiore, and K. Keil (1982). 

And here are a few stones we’ve been fortunate to acquire over the years.  Complete non-NWA stones aren’t easy to find; this pile took a few decades to accumulate.  The largest stone is a little over 2 kilograms (oriented), and the total weight of the lot is ~6 kg.  Some have Monnig / TCU collection numbers.