Question: when did the southern ocean come into existence
[{'answer': 'roughly 30 million years ago', 'provenance': [{'wikipedia_id': '20611428', 'title': 'Southern Ocean', 'start_paragraph_id': 67, 'start_character': 146, 'end_paragraph_id': 67, 'end_character': 174, 'bleu_score': 1.0, 'section': 'Section::::Geography.\n'}]}, {'provenance': [{'wikipedia_id': '20611428', 'title': 'Southern Ocean', 'start_paragraph_id': 67, 'start_character': 0, 'end_paragraph_id': 67, 'end_character': 267, 'bleu_score': 0.950578622812921, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 15468032527738503007}, 'section': 'Section::::Geography.\n'}]}]