Continental lithospheric mantle is heterogeneous in terms of modal and chemical composition. There are fundamental differences between cratonic and younger mantle (Boyd et al., 1997), and non-cratonic mantle has broad compositional variations worldwide (McDonough, 1990). Xenoliths of spinel peridotites in alkali basalts are direct samples of lithospheric mantle but it may not be clear whether a...

Introduction: Planar deformation features (PDFs) in quartz are diagnostic impact evidence. Using light microscopy, it is often impossible to distinguish between PDFs and tectonic deformation lamellae. [1] showed that PDFs can be imaged using a cathodoluminescence (CL) detector in a scanning electron microscope (SEM) and that in SEM-CL images PDFs can be distinguished from tectonic microfracture...

The topographic midlands on Venus comprise about 80% of the surface and an understanding of their mode of formation is essential to unraveling the geologic and geodynamic history of the planet. We explore this question by undertaking a comprehensive geological mapping of the Fredegonde Quadrangle (V-57, 50–751S, 60–1201E, 1:5M scale) that represents the transition zone from the midlands to the ...

Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. The MIT Faculty has made this article openly available. Please share how this access benefits you. Your story matters. [1] The Rachmaninoff, Raditladi, and Mozart peak-ring impact basins on Mercury display a distinctive pattern of tec...

Terrestrial vertebrates show striking changes in species richness across topographic gradients. For mammals, nearly twice as many species per unit area occur in topographically complex regions as in adjacent lowlands. The geological context of this pervasive biogeographic pattern suggests that tectonic processes have a first-order impact on regional diversity. I evaluate ecological, evolutionar...

The surface of Venus displays several tectonized terrains in which the morphologic characteristics of the original materials are almost completely erased by superposed tectonic structures whose large dimensions (»100 km) suggest formation related to mantle convection. The characteristics of these tectonized terrains are in contrast to volcanic units in which tectonic structures are less signifi...

We present and discuss the results of a field-based approach including accurate geological mapping micro- to map-scale structural analysis highlight finite strain pattern recorded in Marguareis Unit, massif deformed at shallow crustal levels boundary between Maritime Ligurian Alps. describe superposed tectonic structures developed under low-grade metamorphic conditions during Alpine collision n...

The Davisian model elucidates landscape development through an orogeny by denudation processes, postulating prolonged still-stand of a landmass following rapid tectonic uplift, ultimately resulting in a peneplain. The Penckian model emphasizes that landscape is shaped by concurrent tectonics and denudation, and includes the primary peneplain as an antithesis against the Davisian end-peneplain b...