Geologists chileans seek to reveal the source of the Antarctic peninsula

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Textbooks in the subject of History and Geography defined formerly the Antartandes as the set of mountain ranges, which serves as an axis to the Antarctic peninsula, and that some geologists considered as an extension of the cordillera of the Andes in the antarctic continent.

This theory dates back to around the 1960s and 1970s, when various specialists postulated this based on the fact that there were the same types of rocks on both sides. In this way, it is stated that the mountain range starts at the border of Colombia and Venezuela, crosses widely Peru and Chile to immerse themselves in the passage of Drake, only to reappear intermittently in the islands Aurora, Georgias of the South, the South Sandwich, South Orkney and South Shetland, and continuing then on to the Antarctic peninsula.

Precisely, this postulate was the subject of discussion just two decades ago. At the beginning of 2000, a group of English investigators and new zealanders recognized a geological structure is greater in the Antarctic peninsula, and proposed that it was composed by blocks of exotic and native, that is to say, that its main constituents have not been formed in situ. Since that time it has intensified the debate and the year 2015 was published an article of the British Antarctic Survey (BAS) who tried to resolve and left towards the idea that the Antarctic peninsula is rather native.

The description about the state it was in the continent of Gondwana and the Antarctic peninsula during the period in mesozoic era is widely detailed in the article “The Gondwanan margin in West Antarctica: Insights from Late Triassic magmatism of the Antarctic Peninsula” (translated into English as “The margin of Gondwana in Antarctica West: visions from the registry magmatic Triassic age late of the Antarctic peninsula”) published in the scientific journal Gondwana Research, one of the most recognized in the area of geology and specialized in the evolution of this ancient continent. “The main objective of this work is to improve reconstructions of the Antarctic peninsula within the western edge of Gondwana, and thus advance our understanding of its configuration,” presents the document.

The first author of this article is the doctoral candidate of the University of Geneva and graduated as a geologist from the University of Chile, Joaquín Bastías, who works with Dr. Richard Spikings of the same university. Also, within the list of authors that collaborated is located Dr. Francisco Hervé, National Prize for Geology chilean recognized for their contributions to the paleogeografía and tectonics of Chile and the Antarctic, and who was awarded in the year 2016, with the Medal to the Path that delivers the Scientific Committee of Research in Antarctica (SCAR for its acronym in English). The results presented in this article are the fruit of a project funded by the Chilean Antarctic Institute (INACH) .

“Our publication comes to contribute with new data with a proposal that combines the two theories. It is effective that the structure proposed in 2000 had a significant role, but apparently moved only locally. In this way, we could say that both hypotheses were correct in some way. And what we propose is that the Antarctic peninsula has a source for-local, that is to say, it was always part of Gondwana,” explained Joaquín Bastías.

In the same way, on the theory that the Andes mountain range joins the sea and appears in the Antarctic, clarifies that: “Apparently, yes they were connected the Antarctic peninsula with South america only in the margin, that is to say, towards the contact with the Pacific ocean (the Pacific ocean did not exist at that time, we call it proto-Pacific), and, apparently, these elements were moved around this neighborhood regional. But it is not precisely as it is proposed suggesting that a certain part of the Antarctic peninsula came and collided with what was in that sector of the Antarctic”.

To carry out this study, we combined new data geocronológicos, geochemical and isotopes in minerals and whole rock. “We have many data of isotope geology; this means that deal with different isotopes such as uranium, oxygen, strontium, neodymium, lead and hafnium. And we also employ chemical analysis of major elements, which are more constitutive of the rocks and the trace elements,” he said.