While looking for the fossilized remains of a tiny organism called Foraminifera, co-author of the study Morgan Schaller from New York's Rensselaer Polytechnic Institute noticed a microtektite
in the sediment he was examining, which belonged to the period when the ancient global warming occurred.
1984): Multiple microtektite
horizons in upper Eocene marine sediments?
They discovered the microtektite
layer above the sediment layer that recorded the reversal and estimated the impact occurred 30,000 years after the beginning of the reversal.
2006); tektites, microtektites
and microkrystites with varying degrees of post-depositional alteration (Smit & Klaver 1981; Montanari et al.
are small glass droplets derived from melting and quenching of terrestrial rocks during hypervelocity meteorite impacts on the Earth (see  and refs.
Analysis of Probable K-T Boundary Microtektites
, Mississippi Embayment, Southeastern Missouri.
This equation is consistent with the higher specific gravities of microtektites
and it may show the role that gas bubbles play in determining specific gravity.
As the excitement mounted, yet more researchers found microtektites
in the K-T boundary layer.
1998), its distinct characteristics have been found to include a combination of all, or some of the following: presence of microtektites
, shocked quartz (Izett, 1991), an iridium spike, sudden increase in clay with geochemical signatures of an origin associated with carbonaceous chondrites (Alvarez and Asaro, 1990; Luck and Turekian, 1983; Shykolyukov and Langmuir, 1998; and others).
These also appear to be microtektites
, they report.
The ferruginous level contains goethite, hematite, glauconitic clasts, scarce foraminifers, and is enriched in Ir, Ni-rich spinels, Co, Cr as well as sanidine spherules that Smit (1982, 1990) interpreted to be altered microtektites
The 'sanidine' spherules were first interpreted as altered microtektites
, but, later became known as microkrystites, which are now best explained as condensation droplets from the hot impact vapour cloud.