In reading the contents of a card, I have come across the following doubt regarding joining the two clauses with a semi colon or keeping them as two separate sentences. The phrase is the following:
Thank you for all of your help these past days; without which, my study would not have been as successful.
The doubt is with the semicolon. As you can see, the first clause stands alone as a grammatically sound sentence: "Thank you for all of your help these past days".
However, my doubt is about the second part: "without which, my study would not have been as successful" can not necessarily stand alone in the same sense.
My question is: Does the fact that the second part of this phrase begins with the preposition without permit the use of the semicolon? Or, is it more grammatically sound to split the sentence into two separate sentences in which the without which refers to the time in the first?