Sure I'll tell you the sample, it was the sample from the upper Paleolithic found in the Satsurblia cave in Georgia found in Jones et al 2015
https://www.nature.com/articles/ncomms9912, there is a chance that this sample is J1b other J1 samples that have been found are the J1 from Bronze Age Anatolia which was found in the same paper as the Mycenaean and Minoan one, J1-P58 in MBA Levant, Sidon and one J1-P58 in Neolithic or Bronze Age Jordan. As for diversity Chiaroni et al 2010 found that J1 has it's highest diversity in eastern Anatolia near lake Van
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2987219/. This haplogroup most certainly originates in west Asia splitting from IJ not in the north Caucasus though but somewhere around eastern Anatolia and the south Caucasus area. At the earliest J1 could've reached Europe during the Mesolithic with EHG but only in NE Europe as suggested by the J* sample from Mesolithic Karelia which is believed to possibly be J1 and how there is a J1 clade exclusive to Finns which is pretty basal. Other clades would've expanded from West Asia later during the Bronze Age, Classical Era, Roman Era etc.