ABSTRACT

The Mencué Batholith, western North Patagonian Massif, includes three major bodies. The Mencué Granodiorite, Cura Lauquén Granite and La Blancura Syenogranite. There are dikes of granitic and basaltic rocks cutting the above-cited rocks.

The Mencué Batholith represents several episodes of magmatism, with ages varying between 294 and 239 Ma. The Mencué Granodiorite and the Cura Lauquén Granite are solid-state deformed and are S-type. They have high-K and normal calc-alkaline affinities. These rocks contain significant quantities of subduction-zone chemical components that decrease towards younger lithofacies. La Blancura Syenogranite lack subduction zone chemical components and represent A-type granite, typical of within-plate magmatism. The partial melting of metapelites could be the process of formation of these bodies. The older lithofacies of the Mencué Batholith, found westernmost, display a stronger deformation, but there is a progressive eastward change to younger and mildly deformed bodies and even non-deformed bodies. We conclude that the evolution of the Mencué Batholith start in the Sakmarian-Roadian (Early Permian) period. At this time, a subduction zone was active to the west and its thermal influence affected sedimentary or metamorphic rocks producing S-type granites

During the Wordian and Capitanian, (Middle Permian) periods, the Mencué Batholith was mildly deformed, possibly in the process of the vanishing of the deformation and has a minor subduction chemical signature.

Between the Wuchiapingian and Olenekia periods, the alkaline facies of the Mencué Batholith show an absence of deformation and the characteristics of within-plate magmatism.

The Early Permian magmatic events in the western North Patagonian Massif are represented by the older bodies of the Mencué Batholith and were produced by subduction in the western margin of the Gondwanan continent.

The Late Permian-Early Triassic magmatic events show a noticeable decreasing influence of subduction and an increasing influence of within-plate chemical components.

摘要

北巴塔哥尼亚地块西部的Mencué岩基包括三个主要主体。Mencué花岗闪长岩，CuraLauquén花岗石和La Blancura Syenogranite。有花岗岩和玄武岩岩堤切割上述岩石。

Mencué岩床代表着几次岩浆活动，年龄在294至239 Ma之间。Mencué花岗闪长岩和CuraLauquén花岗石是固态变形的，属于S型。它们具有高K和正常的钙碱性亲和力。这些岩石包含大量的俯冲带化学成分，这些化学成分会朝着较年轻的岩相减少。La Blancura Syenogranite缺乏俯冲带化学成分，代表板内岩浆作用的典型A型花岗岩。变质岩的部分熔融可能是这些物体形成的过程。孟库岩床的较老岩相位于最西端，表现出更强的变形，但向东逐渐向年轻，轻度变形的物体乃至未变形的物体转变。我们得出的结论是，孟库岩床的演化始于萨克马里-罗马尼亚（早二叠纪）时期。这时，一个俯冲带向西活跃，其热影响影响了产生S型花岗岩的沉积或变质岩。

在Wordian和Capitanian（中二叠纪）时期，Mencué岩基轻微变形，可能是在消失的过程中，并且具有较小的俯冲化学特征。

在五叠亚平时期和奥列尼克期之间，孟库岩床的碱性相显示没有变形，并且没有板内岩浆作用。

北巴塔哥尼亚地块西部的二叠纪早期岩浆事件以孟库岩床的较早遗体为代表，是在冈瓦纳大陆西部边缘俯冲产生的。

晚二叠纪-早三叠世岩浆事件显示出俯冲作用明显减小，板内化学成分影响增大。