Skip to Main Content
Skip Nav Destination
GEOREF RECORD

Reactivated lithospheric-scale discontinuities localize dynamic uplift of the Moroccan Atlas Mountains

Meghan S. Miller and Thorsten W. Becker
Reactivated lithospheric-scale discontinuities localize dynamic uplift of the Moroccan Atlas Mountains
Geology (Boulder) (January 2014) 42 (1): 35-38

Abstract

The Atlas Mountains of Morocco, an example of an intracontinental mountain belt, display only modest tectonic shortening, yet have unusually high topography. We present new evidence from receiver functions and shear-wave splitting for localized, nearly vertical offset deformation of both crust-mantle and lithosphere-asthenosphere interfaces at the flanks of the High Atlas. These offsets coincide with the locations of Jurassic-aged normal fault reactivation that led to tectonic inversion of the region during the Cenozoic. This suggests that a lithospheric-scale discontinuity is involved in orogeny. Another significant step in lithospheric thickness is inferred within the Middle Atlas. Its location corresponds to the source of regional Quaternary alkali volcanism, where the influx of melt induced by the shallow asthenosphere appears to be restricted to the lithospheric-scale fault on the northern side of the range. Inferred stretching axes from shear-wave splitting are aligned with the highest topography, suggesting along-strike asthenospheric shearing in mantle flow guided by lithospheric topography. Isostatic modeling based on these improved crustal thickness and offset estimates indicates that lithospheric thinning alone does not explain the anomalous Atlas topography. Instead, an upwelling component induced by a hot mantle anomaly is also required to support the Atlas, suggesting that the timing of uplift is contemporaneous with the recent volcanism in the Middle Atlas. These observations provide a refined understanding of intracontinental orogeny and localized volcanism.


ISSN: 0091-7613
EISSN: 1943-2682
Coden: GLGYBA
Serial Title: Geology (Boulder)
Serial Volume: 42
Serial Issue: 1
Title: Reactivated lithospheric-scale discontinuities localize dynamic uplift of the Moroccan Atlas Mountains
Affiliation: University of Southern California, Department of Earth Sciences, Los Angeles, CA, United States
Pages: 35-38
Published: 201401
Text Language: English
Publisher: Geological Society of America (GSA), Boulder, CO, United States
References: 36
Accession Number: 2014-004534
Categories: Solid-earth geophysicsApplied geophysics
Document Type: Serial
Bibliographic Level: Analytic
Annotation: GSA Data Repository item 2014009
Illustration Description: illus. incl. geol. sketch map
N31°00'00" - N34°00'00", W08°00'00" - W02°00'00"
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute. Reference includes data from GeoScienceWorld, Alexandria, VA, United States. Reference includes data supplied by the Geological Society of America, Boulder, CO, United States
Update Code: 201404
Close Modal

or Create an Account

Close Modal
Close Modal