The Eastern Andean Metamorphic Complex at Península La Carmela (48°50’S) consists of quartz-rich metaturbiditic sequences with tectonic slices of pillow metabasalt bodies deformed under low-grade metamorphic conditions. Previous and new detrital zircon U–Pb geochronological data from metasandstones indicate a preferred early Carboniferous maximum depositional age of the protolith, interpreted from the youngest single zircon grains of several metasedimentary rocks in the area. The wide spectrum of zircon ages from Península La Carmela, includes Neoproterozoic-early Paleozoic components and subordinate ancient zircon grains (> 2200 Ma). They were sourced from cratonic regions and/or reworked material from older metasedimentary successions and plutonic belts in southwestern Gondwana (e.g., North Patagonian and Deseado massifs or from the Tierra del Fuego Igneous and Metamorphic Complex). The pillow metabasalts have geochemical affinities of normal mid-oceanic ridge basalts and island-arc tholeiites with Nb–Ta negative anomalies, derived from a depleted mantle source (εNd_t of + 6 and + 7.5). In consideration that pillow metabasalts with ocean island basalt affinities are reported, we propose that metaturbiditic successions and metabasalts were tectonically juxtaposed within a pre-Permian accretionary wedge of an active continental margin, after the development of island arcs and back-arc marginal basins.

Península La Carmela (48°50'S) 的东安第斯变质复合体由富含石英的变浊积岩层序和枕状变玄武岩体的构造切片组成，这些构造切片在低级变质条件下变形。来自变砂岩的先前和新碎屑锆石 U-Pb 地质年代学数据表明，原岩的优选早石炭世最大沉积年龄，从该地区几种变沉积岩的最年轻的单个锆石颗粒解释。Península La Carmela 的锆石年龄范围很广，包括新元古代-早古生代成分和次级古代锆石颗粒（> 2200 Ma）。它们来自克拉通地区和/或来自冈瓦纳西南部较旧的变沉积层序和深成带的再加工材料（例如，北巴塔哥尼亚和 Deseado 地块或来自火地岛火成岩和变质复合体）。枕状变玄武岩具有正常洋中脊玄武岩和岛弧拉斑岩的地球化学亲和性，具有 Nb-Ta 负异常，源自贫化地幔源（εNd+ 6 和 + 7.5 的_t）。考虑到已报道了具有洋岛玄武岩亲缘关系的枕状变玄武岩，我们提出，在岛弧和弧后边缘盆地发育之后，变浊积岩层序和变玄武岩在活动大陆边缘的前二叠纪增生楔内在构造上并列。