Dear Huiming, I have loaded samples of microspherule beds from the Barite Syncline for triple oxygen analysis. Maybe you already did this? I dont expect to find a meteorite signature but who knows? I had to shift the 253 over to O2 analysis because of problems with the 252 so I'm temporarily out of the S-isotope business. The meteorite game for oxygen analysis is very active: 4 abstracts submitted on Tuesday to the LPSC. Very Best, Doug Douglas Rumble [log in to unmask] Geophysical Lab 5251 Broad Branch Rd., NW Washington, DC, 20015-1305 202-478-8990