Tentative Si extraction methods 2

Sample size: ~5 g

1. Dry sample overnight. Weigh and record sample weight.
2. Remove organics with HNO3 and a pinch of KClO3. Place sample in boiling water bath. Digest for 1.5 hours. Centrifuge and decant supernatant (3x).
3. Remove carbonates with 10% HCl. Digest for 15 minutes or until reaction stops. Centrifuge and decant supernatant (3x).
4. Deflocculate sample with 5% (NaPO3)6. Place in mechanical shaker for 8 hours. Do not centrifuge.
5. Extract clays (less than 4 microns) using float times outlined by Tanner & Jackson (1947).
6. Float sample using 3NA2 • (WO4 •9WO3)• H2O. Set specific gravity to 2.3. Extract pytoliths using pipette. Centrifuge and decant supernatant (3x).
7. Place extracted phytoliths in 1 dram vial.