Question: what is the term for the thick layer surrounding earth’s outer core
[{'answer': 'mantle', 'provenance': [{'wikipedia_id': '146249', 'title': "Earth's outer core", 'start_paragraph_id': 1, 'start_character': 142, 'end_paragraph_id': 1, 'end_character': 148, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '146249', 'title': "Earth's outer core", 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 366, 'bleu_score': 0.596083952620543, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 1085497565970737828}, 'section': 'Section::::Abstract.'}]}]