The first suggests that the clarification was effective. The second is a polite acknowledgment that the clarification was received; it may or may not be saying that it (the clarification) worked.What is the difference between the following sentences?
They are both formal, although some may shun the use of phrasal verbs in formal text/correspondence and hence prefer "Thank you for clarifying that" instead.Which one is more formal?
…ome may shun the use of phrasal verbs in formal text/correspondence ….
What is the difference between the following sentences?
Thank you for clearing that up. / Thank you for your clarification.
Which one is more formal?
That's different. There are various aspects that contribute to formality."inform" is a bit more formal than "tell".
The sentence with "clarification" is more formal purely because the verb "clarify" is generally seen as more formal than "clear up". It has nothing to do with the latter being a phrasal verb.