Early Miocene Antarctic glacial history: new insights from heavy mineral analysis from ANDRILL AND-2A drill core sediments

Autor(es)

Iacoviello, Francesco ^[1] ; Giorgetti, Giovanna ^[2] ; Memmi, Isabella Turbanti ^[2] ; Passchier, Sandra ^[3]

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Inst Oceanog, BR-05508120 Sao Paulo, SP - Brazil

^[2] Univ Siena, Dipartimento Sci Fis Terra & Ambiente, I-53100 Siena - Italy

^[3] Montclair State Univ, Dept Earth & Environm Studies, Montclair, NJ 07043 - USA

• Tipo de documento: Artigo Científico
• Fonte: INTERNATIONAL JOURNAL OF EARTH SCIENCES; v. 104, n. 3, p. 853-872, APR 2015.
• Citações Web of Science: 2

Resumo

The present study deals with heavy mineral analysis of late Early Miocene marine sediments recovered in the McMurdo Sound region (Ross Sea, Antarctica) during the ANDRILL-SMS Project in 2007. The main objective is to investigate how heavy mineral assemblages reflect different source rocks and hence different provenance areas. These data contribute to a better understanding of East Antarctica ice dynamics in the Ross Sea sector during the Early Miocene (17.6-20.2 Ma), a time of long-term global warming and sea level rise. The AND-2A drill core recovered several stratigraphic intervals that span from Early Miocene to Pleistocene and it collected a variety of terrigenous lithologies. The heavy mineral assemblages of the lower 650-m-thick sedimentary succession were analyzed through SEM observations and SEM-EDS microanalyses on heavy mineral grains. The heavy mineral analysis shows that the sediments are a mix of detritus dominated by McMurdo Volcanic Group sources most likely located in the present-day Mount Morning area (Proto-Mount Morning) with minor contribution from Transantarctic Mountains source rocks located west of the drill site. The heavy mineral assemblages in Interval 1 indicate that between 20.2 and 20.1 Ma, the grounding line of the ice sheet advanced to a position near the present-day Mount Morning volcanic center. During deposition of Interval 2 (20.1-19.3 Ma), the ice sheet most likely experienced a dynamic behavior with interval of ice advance alternating with periods of ice retreat, while Interval 3 (19.3-18.7 Ma) records further retreat to open water conditions. A dynamic behavior is noted in Interval 4 (18.7-17.6 Ma) with a decreasing contribution of materials derived from the basalts of the Mount Morning volcanic center located to the south of the drill site and a consequent increasing contribution of materials derived from the Transantarctic Mountains to the west of the drill site. (AU)

• Processo FAPESP: 12/18304-3 - Evolução ambiental e climática do Rio Amazonas e a Margem Setentrional Brasileira usando minerais argilosos
• Beneficiário: Francesco Iacoviello
• Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado