Southern Patagonian plateau basalts and deformation: Backarc testimony of ridge collisions

摘要: Abstract The distribution and volume of Tertiary Patagonian plateau basalts the evolution fold thrust belt between 46° 49°S appear to be closely tied with ridge-trench interactions along continental margin west. Eocene south 43°S are associated a gap in arc can related proposed collision Aluk-Farallon ridge against trench at this time. Eruptions Late Miocene Recent time-transgressive slab windows underlying mantle generated by segments Chile 10–14 Ma 6 Ma. principal deformation predates eruption also appears collision. Comparison three distinct suggests that basalt erupted increases length collided segment. Almost all have OIB-like (ocean island basalt) trace element signatures showing source region changed little Plateau more arc-like contaminated crust. Relative melting percentages inferred from chemistry correlate volumes implying spatial temporal changes temperatures correlated windows.