Color change and disintegrating in water of heated bricks.

(A) An unoriented specimen taken from the sun-dried bricks collected in the field (SF12E) and 21 specimens taken from the same brick which had been heated in the lab to 100–700⁰C. Notice the gradual change in color which is clearly visible from ~400⁰C and above. (B) The same specimens as in (A) after placing them in open paleomagnetic plastic boxes and gently dripping water into the box until the specimens are completely covered in water. The unheated mud brick material and all samples which had been heated to 400⁰C or less disintegrated immediately in the water. Most of them disintegrated into fine grains, with the exception of the sample heated to 400⁰C which broke into coarse grain material. The samples heated to 430⁰C and more were almost unaffected by the water.

(TIF)