Map (original size 3072 x 4096 pixels)
showing the uppermost layer of ejecta
in the oceanic drill core ODP Leg 207,
discernible by the orange tinted
layer. Note that the carbonates (light
and dark blue particles) and quartz
(purple) are restricted
A large area and high resolution mapping allows to gain an overview and to see details of a sample in a single map. The specimen analyzed was a piece of an oceanic drill core containing ejecta from the Chicxulub crater in Mexico. The meteorite that caused this crater around 65 million years ago is said to be the reason for the extinction of the dinosaurs.
A 4096 x 3072 pixel map was obtained from the ejecta layer in the specimen. Thanks to the capabilities of the XFlash® detectors the mapping could be performed in only 33 minutes, using an input count rate of 500 kcps.
The high resolution composite element map displays a distinct layer in the uppermost millimeters of the ejecta deposit. It comprises abundant calcite (CaCO3) and dolomite [(Ca,Mg)CO3] spherules, few shocked quartz (SiO2) fragments and aluminosilicate grains such as feldspar [(K,Na)AlSi3O8, NaAlSi3O8 – CaAl2Si2O8]. The dolomite spherules have irregular serrated boundaries enclosed by a layered clay shell indicating impact-induced mechanical and thermal stress during the impact event. The porous calcite spherules resemble experimentally produced degassing textures.