Vertical-Axis Rotations During Tectonic Development of the Central Andes in Bolivia, Southeastern Peru, and Northwestern Argentina

9706193巴特勒：安第斯会聚边缘在南纬20度左右有一个明显的弯曲，与高地地区重合。有几种模型可能可以解释这种弯曲，包括顺斜弯曲。初步的古地磁数据表明，垂直轴的旋转影响了安第斯山脉中部的新生代岩石单位，远至玻利维亚东部的科迪勒拉。在弯曲的北翼通常是逆时针方向，在弯曲的南翼通常是顺时针方向。然而，这些自转的时间分布却鲜为人知。该项目的目标是确定造山斜弯曲的前新近纪成分，并确定始新世和渐新世-早中新世变形的范围和类型，包括区域壳域和连接它们的断层。该项目的成功完成，除了对高原的地球动力学发展提供重要见解外，还将大大增加对造山斜构造、与地壳区域边界有关的旋转以及造山斜中褶皱和冲断带的结构发展的认识。

9706193 Butler The Andean convergent margin exhibits a distinct bend centered at about 20o south latitude, coincident with the Altiplano region. Several models can possibly account for this bend, including oroclinal bending. Preliminary paleomagnetic data indicates that vertical-axis rotations have affected Cenozoic rocks units in the central Andes as far inboard as the eastern Cordillera of Bolivia. These are generally counterclockwise on the north limb and clock wise on the south limb of the bend. However, the temporal distribution of these rotations are poorly known. The goals of this project are to determine the pre-Neogene component of oroclinal bending and to define the extent and style of Eocene and Oligocene-Early Miocene deformation, including regional crustal domains and the fault that bound them. As well as providing important insights in the geodynamic development of the Altiplano, successful completion of this project would add significantly to knowledge of oroclinal structures, rotations associated with boundaries of crustal domains, and the structural development of fold and thrust belts in oroclines.