bomb sag

bomb sag

[′bäm ‚sag]
(geology)
Depressed and deranged laminae mainly found in beds of fine-grained ash or tuff around an included volcanic bomb or block which fell on and became buried in the deposit.
References in periodicals archive ?
The deposit landed in the volcanic sediment, created a divot (or bomb sag), eventually solidified and remains in the same location today.
Dufek and his collaborators at the University of California-Berkeley received enough data to determine the size, depth and shape of the bomb sag.
No matter the type of particle, the saturated beds consistently produced impact craters similar in shape to the Martian bomb sag.
"We were only able to study one bomb sag at one location on the Red Planet.
"That's a bomb sag," says rover lead scientist Steve Squyres.
"The fact that it's a bomb sag says there was some kind of violent emplacement process, some kind of high-energy process," notes Squyres.
And, says Squyres, "if you saw a bomb sag like this on Earth, you would say those sediments were wet--like soft, deformable mud."