No abstract

2D neutron diffraction imaging of an ammonite fossil was carried out at high-intensity total diffractometer NOVA in J-PARC. Observed diffraction profiles consist of calcite, siderite and amorphous structures. Most of part in the ammonite is calcite. The calcite image shows air chambers divided by septa in the spiral shell. Siderite is observed only in the body chamber. Amorphous structure is observed in both the protoconch and the inner whorls. Based on the crystal structures, their chemical compositions are discussed.