Ask A Scientist General Science Archive

Question:  What is "marl" and what is the process for its formation?
 remy rodden

Answer:
Marl is a rock containing clay and calcium carbonate.  It
is formed from the erosion of other rocks during weathering;
as rocks erode, small sedimentary particles--sand, silt,
and clay--pile up on top of each other.  Eventually, these
sedimentary particles become compacted together to form a
new rock.  The type of new rock that is formed depends on
the original rock that was eroded and on the nature of the
erosion.  If the new rock contains predominantly clay
and calcium carbonate, it is called marl.

The most common use for marl is as a fertilizer for soils
that are deficient in calcium carbonate (lime).

TRIVIA TIME: Marl is also the name given to fibers
obtained from peacock feathers.  These fibers used to be
used (and perhaps still are) in making artificial flies
for fly-fishing.
-Grant