Ventifacts and associated weathering forms in early Albian carbonates of the Cantabrian coast (Noja, Northern Spain) B. Ábalos a, ⁎, J. Elorza b a Departamento de Geodinámica, Universidad del País Vasco, UPV/EHU, PO Box 644, E-48080 Bilbao, Spain b Departamento de Mineralogía y Petrología, Universidad del País Vasco, UPV/EHU, PO Box 644, E-48080 Bilbao, Spain abstract article info Article history: Received 3 October 2012 Received in revised form 18 April 2013 Accepted 19 April 2013 Available online 28 April 2013 Keywords: Ventifacts Carbonate rocks Beach dynamics Albian Quaternary Spain Field descriptions of ventifacts sculpted in wind-abraded, Albian carbonate rock protrusions are presented in this study, as well as of the closely related, wind-influenced chemical weathering features that interfere or converge morphologically with them. Descriptions of two new ventifacts (“bows” and “pinnacles”) are presented. “Bows” compare to the hydrodynamic forward parts of ship hulls, whereas “pinnacles” are sub- circular rounded salients that form clusters in vertical rock faces turned to the wind. Additionally, “sidewall tafoni” are described in non-detrital rocks. The ventifacts are used to identify geomorphically effective winds and to deepen in the knowledge of wind-driven weathering and abrasion processes. These erosional forms (not reported so far in northern Spain) are currently active in sand-dominated beach environments under a humid, temperate climate. Inactive and reactivated forms variably erased by current coastal dynamics are also described. These share the orientation characteristics of the currently active ones, and are interpreted as reflecting unconstrained past wind conditions over decadal or longer timescales. In spite of their interest as paleoenvironmental indicators, the geomorphic associations described exhibit a low preservation potential in the area, and no fossil equivalents have been described so far in older (uplifted or submerged) Quaternary coastal platforms of northern Spain. © 2013 Elsevier B.V. All rights reserved. 1. Introduction Hard rock surfaces and cobbles/boulders abraded by wind-carried particles, notably by sand, exhibit a variety of morphological features that may be used to infer wind direction, sediment mobility and envi- ronmental conditions (Schlyter, 1995; Knight, 2008). These groups of erosional landforms are collectively known as ventifacts. Typically, the wind-abraded surfaces are oriented either parallel or normal to the wind direction, and exhibit a range of dip angles, from sub- vertical to sub-horizontal. Current ventifact formation on Earth is known (among other settings) in deserts (e.g., Grolier et al., 1980) and coasts (Knight, 2005) subjected to either cold (Gillies et al., 2009), warm humid (Hickox, 1959) or dry climatic conditions. In these envi- ronments, coastal salt spray, chemical or biochemical weathering can produce features that interfere or converge morphologically with venti- facts (Smith, 2009). These geomorphic associations are interpreted as reflecting average regional wind conditions over decadal or longer time scales, and their preservation potential in the geological record (e.g., Thompson and Worsey, 1967; Els, 1998) permits them to be used as paleoenvironmental indicators (e.g., André and Hall, 2005). Their long history of investigation is also the basis for the interpreta- tion of similar geomorphic features identified in images obtained by satellites and other remotely operated vehicles sent to planets such as Mars (see Knight, 2005; Laity and Bridges, 2009, and references therein). Eolian sediment dynamics are well known in some beaches of the humid/temperate coastal setting of northern Spain (e.g., Monge- Ganuzas et al., 2003; Iriarte et al., 2004; Flor and Flor-Blanco, 2005; Pascual et al., 2007). By contrast, to our knowledge no records of hard rock eolian abrasion forms have been reported so far. This paper presents for the first time field observations of wind-abraded, early Albian (López-Horgue et al., 2010) carbonate rock protrusions, as well as of closely related wind-influenced weathering features. We also provide new descriptions of their macro-, meso- and micro- scale characteristics, sculptured in sand-dominated beach environ- ments. They are used to identify the geomorphically effective winds (current and past) and to enhance knowledge of wind-driven chemical weathering and abrasion processes. 2. Geological setting The study area (Noja; Fig. 1) is located in the eastern Cantabrian coast of northern Spain. This coast trends roughly E–W along the southern Gulf of Biscay. Its eastern part (including the Noja area) is geologically constrained by the western prolongation of the Pyrenees in the Basque-Cantabrian Basin, which includes a stratigraphically complex Mesozoic sedimentary fill inverted during the Paleogene Geomorphology 195 (2013) 66–83 ⁎ Corresponding author. E-mail address: benito.abalos@ehu.es (B. Ábalos). 0169-555X/$ – see front matter © 2013 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.geomorph.2013.04.028 Contents lists available at SciVerse ScienceDirect Geomorphology journal homepage: www.elsevier.com/locate/geomorph