Upper Cenomanian–Turonian clay mineral assemblages of sediments cropping out in the Western High Atlas basin are studied in four sections. Smectite and mixed-layer illite-smectite (I-S) have been identified as major constituents of the deposits. The composition of clay associations in black shales and associated sediments varies considerably according to age, but usually depends either on the general lithology, the abundance of organic matter, or the depth of burial. A distinct correlation is evident between clay mineral distribution and sea-level. Smectite and mixed-layer I-S with greater percentages of smectite layers increase in sediments deposited during transgressive periods, whereas they decrease progressively in the shallower facies deposited during regression in favour of illite and mixed-layer I-S with a greater percentage of illite. The vertical evolution and lateral distribution of clay assemblages and their relationships with sea-level as well as the palaeogeographic conditions prevailing during the Late Cenomanian–Turonian period (flattened topography and arid climate), indicate a detrital origin of the smectite minerals and a distribution pattern controlled by differential settling processes.

In the western High Atlas basin, the evolution of the clay assemblage of the Upper Jurassic–Cretaceous sedimentary series is controlled by palaeogeographic changes of the basin and by burial diagenesis.The effects of burial are expressed by an increase in the proportions of illite and chlorite with depth, a decrease of expandability of smectite minerals and by a decrease in the Kübler Index.Kaolinite is preserved at greater depths than smectite, but also tends to diminish in abundance. TEM observations show that idiomorphic pseudo-hexagonal crystals of illite increase in size and abundance downwards, especially in the sandy levels.In the Agadir section, the main change in the clay mineral evolution related to late diagenesis occurs at the Mid-Albian, corresponding to a burial depth of about 1800 m; in the Essaouira section it occurs at the Lower Tithonian at a burial depth of about 2100 m.Considering the different geothermal gradient between Agadir (36ºC km–1) and Essaouira (27ºC km–1), the disappearance of smectite occurs at the same temperature in these two sites (60 to 65ºC).

The Maastrichtian-Palaeogene series of the Western High Atlas and Meseta Basins in Morocco are particularly rich in palygorskite. The present work is aimed at clarifying the genesis of palygorskite from the interbedded facies and gaining an understanding of their relationships with the depositional environment. The mineralogical characteristics of palygorskite from these series were studied by X-ray diffraction (XRD) and electron microscopy (SEM/TEM). The palygorskite content and microstructure show large geographical and stratigraphical variations in the deposits studied. The palygorskite occurrence is directly related to palaeobathymetry, since it is the dominant clay mineral in shallow marine and restricted environments. According to the morphology of palygorskite crystallites, four types of textures were distinguished. These types of palygorskite are polygenetic, formed by chemical precipitation, by the recrystallization of smectite clays or reworked by wind or water from sub-aerial environments. The difference between the two studied sub-basins with respect to palygorskite occurrence is attributed to the palaeomorphology of the hinterlands, to the tectonic differentiation and to the physical-chemical conditions of seawater.

The Barbary macaque Macaca sylvanus is imperiled throughout its distribution range in north-west Africa. In the summers of 2009 and 2013 we used the piecewise line-transect distance sampling method to study the southernmost population in the High Ourika valley, in the western High Atlas of Morocco. This rugged mountainous area is dominated by degraded fruit-poor environments, mostly holm oak Quercus rotundifolia forest patches. We located four and two groups in 2009 and 2013, respectively, and estimated population sizes of 122 and 84 individuals. The mean group size was 12 individuals in 2009 and 46 in 2013. The estimated mean density (individuals per km2) varied among groups (10–171), with a mean of 27. The population structure varied significantly among groups and years. Our records comprised 24.8 and 20% adult males, 24.8 and 22% adult females, 11 and 13% subadults, 13 and 17% juveniles and 26.4 and 26.3% infants in 2009 and 2013, respectively. In both years 50–56% of the population consisted of young individuals (subadults excluded). The mean sex ratio among adults was 1 : 1. The apparent fecundity rate was 1.06 infants per adult female. We propose conservation actions to protect this peripheral population of Barbary macaques.