SQL> CREATE TABLE test_delete (id NUMBER, name VARCHAR2(10));
Table created.
SQL> CREATE INDEX test_delete_idx ON test_delete (name);
Index created.
SQL> INSERT INTO test_delete VALUES (1, 'BOWIE');
1 row created.
SQL> COMMIT;
Commit complete.
SQL> DELETE test_delete WHERE id = 1;
1 row updated.
SQL> SELECT file_id,block_id FROM dba_extents WHERE segment_name='TEST_DELETE_IDX';
FILE_ID BLOCK_ID
---------- --------------- 5 3441
SQL> ALTER SYSTEM DUMP DATAFILE 5 BLOCK 3442;
System altered.

SQL> DELETE test_delete WHERE id = 1;
1 row updated.