Question: when was the last date antarctica was free of ice
[{'answer': 'about 34 million years ago', 'provenance': [{'wikipedia_id': '18959138', 'title': 'Antarctica', 'start_paragraph_id': 48, 'start_character': 532, 'end_paragraph_id': 48, 'end_character': 558, 'bleu_score': 1.0, 'section': 'Section::::Geology.:Geological history and palaeontology.:Gondwana breakup (160–23 Ma).\n'}]}, {'provenance': [{'wikipedia_id': '18959138', 'title': 'Antarctica', 'start_paragraph_id': 60, 'start_character': 0, 'end_paragraph_id': 60, 'end_character': 1223, 'bleu_score': 0.7454943412077001, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 9252238834612660999}, 'section': 'Section::::Climate.\n'}]}]