Identify cause of unusual transaction log growth
This SQL shows queries with most "logical_writes":

SELECT TOP 100
    st.text,
    execution_count,
    total_elapsed_time,
    total_worker_time,
    total_logical_reads,
    total_logical_writes,
    total_physical_reads,
    total_clr_time,
    creation_time, last_execution_time,
    pl.query_plan
FROM sys.dm_exec_query_stats ps with (NOLOCK)
    Cross Apply sys.dm_exec_sql_text(ps.sql_handle) st
    Cross Apply sys.dm_exec_query_plan(ps.plan_handle) pl
ORDER BY total_logical_writes desc
OPTION (RECOMPILE);


This T-SQL could help to find direction, but it is not really what you asked for, as logical write != write. and logical write != log write. 

It could be very very interesting to find more complete answer to your question.