“Inhabitants of rustic parts of the world”: John Locke’s collection of drawings and the Dutch Empire in ethnographic types

This article analyses a collection of 26 watercolour drawings which portray ethnographic types from the Americas, Asia, and Africa. These drawings, presently kept at the British Library, were made for John Locke by his servant Sylvester Brounower during Locke’s exile in the Netherlands in the 1680s.     

Fracture spacing during hydro‐fracturing of cap‐rocks

Layered low permeability rock units, like shales, represent seals or ‘cap‐rocks’ in a variety of geological settings. A continuous increase in the fluid pressure gradients across a virtually impermeable rock layer will ultimately lead to hydro‐fracturing. Depending on the boundary conditions, such fracturing may lead to the formation of a set of sub‐parallel cracks oriented more or less perpendicular to the cap‐rock layer. In this article, we propose a new numerical model that describes interactions between multiple cross‐cutting fractures in an elastic low permeability rock layer. The width of each fracture and the spacing between them are modeled as a force balance between the fluid pressure and the elastic forces in the cap‐rock and between each fracture. The model indicates that the system of fractures evolves toward a spatially periodic steady‐state distribution with a fixed fracture spacing and aperture. The results are similar for incompressible and compressible fluids. The steady‐state conditions depend on only two dimensionless parameters, and the fracture spacing is only weakly dependent on the cap‐rock thickness. This is in contrast to fracturing produced by simple extension of an elastic rock layer beyond the fracture strength, in which case fracture spacing is proportional to layer thickness.     

A new approach to Corystospermales based on Triassic permineralized stems from Argentina

Anatomically preserved mature stems of late Middle Triassic corystosperms from the Paramillo Formation of Argentina are described and assigned to Cuneumxylon spallettii gen. nov. et sp. nov. The silicified specimens show features of the pith, primary xylem and successive rings of secondary xylem and phloem. The most striking characteristic is the anomalous secondary growth, represented by secondary xylem bounded by arcs of secondary phloem probably derived from successive repositioned cambia. Cuneumxylon has two kinds of unusual centrifugal secondary growth. The first shows unequal activity of different portions of the cambium on the circumference of the axes; the consequent restriction of cambial activity to certain restricted areas develops wedged stems, which often split. The second produces polyxylic stems following supernumerary cambial activity. As in extant plants growing in arid regions, the included phloem and the associated parenchyma may have had functional value avoiding desiccation of the outer tissues of the stem during droughts. Anatomical features of other Corystospermaceae were used to determine systematic affinities and to establish relationships among medullosans, corystosperms and cycads.     

First record of fossil woods from the Mariño Formation (Miocene), Mendoza,Argentina and their palaeobiogeographical implications

The first Miocene records of silicified fossil woods from the Mariño Formation, Potrerillos area, Andes Precordillera, Mendoza province, Argentina are described. Rhaphithamnoxylon artabeae gen. et sp. nov. is described as the first fossil wood referable to Verbenaceae from Argentina. This new fossil species is related to extant Rhaphithamnus Miers, sharing the following anatomical features: diffuse porosity, distinct growth ring boundaries, numerous small to very small vessels, commonly in radial multiples, 1–3 seriate rays, and heterocellular and scarce paratracheal axial parenchyma. Rhaphithamnus contains only two extant species: R. spinosus (A.L. Juss.) Moldenke, which occurs in the Valdivian forests of Chile and Argentina, and R. venustus (Philippi) Robinson, which is endemic to the Juan Fernández Islands. Representatives of Verbenaceae are distributed predominantly in the Americas from Patagonia (Argentina) to Canada, and they are inferred to have originated in South America. The fossil wood described herein provides new age and geographical constraints on the raphithanoid lineage within Verbenaceae. Other fossil woods recorded from the Mariño level are retained under open nomenclature, as they possess a combination of mostly solitary broad vessels, and smaller vessels in radial multiples or in clusters, with numerous, vasicentric to confluent axial parenchyma, and heterocellular, high rays. Thus, they have features akin to dicotyledonous lianas or vine-like or small shrub species.     

Seismic performance of historical vaulted adobe constructions: a numerical case study from Yazd,Iran

Past earthquakes have demonstrated that historical vaulted adobe buildings are highly vulnerable to seismic actions. Hence, it is crucial for such building typologies to be evaluated in terms of seismic capacity. To this end, this article deals with the seismic performance of historical vaulted adobe houses from the city of Yazd, Iran as one of the seismically active areas of the world and possessing a very rich adobe heritage. Thus, and based on a detailed geometrical survey, a representative sample of adobe houses from Yazd was studied using a simplified in-plane analysis based on three geometric indexes. Concerning the out-of-plane behavior, a deeper assessment was conducted by performing a numerical study, where the main influential parameters on the seismic behavior of vaulted adobe buildings were considered. The numerical analyses were carried out by adopting the limit analysis theory implemented in the Block2D software. The results obtained indicate the safe in-plane behavior of most of the houses and the safe out-of-plane response of the sample under gravitational loads. However, the sample out-of-plane safety under earthquake-induced loads seems to be a matter of concern.     

Technical Strategies for Conservation of Earthen Archaeological Architecture

The preservation of earthen architectural heritage is extremely complex due to the diversity of its constituent materials and potentially rapid physical deterioration. Interventions on historic earthen architecture throughout the world have shown very distinct levels of success, but there is no single procedure or combination of conservation procedures that guarantee success. One of the problems is the lack of knowledge about the behaviour of soil as the material component, and its relationships both with other materials, and associated natural and cultural environments. This article analyses some technical considerations that have influenced the preservation of earthen archaeological remains, through critical analysis of the existing bibliographic references from the proceedings of specialized international conferences that have taken place in the last twenty years.     

Fire and ritual: bark hearths in South-American Tupiguarani mortuary rites

High proportions of bark pieces (up to 85% of the charcoal content) were found in several hearths from Morro Grande archaeological site (Southeastern Brazil). This site, dated between 3220–2840 and 1820–1390 yrs cal BP, is associated to the Tupiguarani Tradition, attributed to supposed ancestors of Tupinambá native populations, who occupied the major part of the Brazilian coast in the XVIth century. Bark hearths, archaeologically associated with the mortuary ritual, were found encircling a funerary urn and associated with ceramic fragments painted with elaborated patterns in black, white, and red. Other hearths, spatially isolated from the funerary area, were associated to fragments of utilitarian non-painted ceramics and therefore attributed to domestic contexts. These ones presented few or no bark fragments. It is clear that bark was intentionally selected as fuel for the funerary hearths. Although bark is related, in historic accounts, as a specialized firewood for ceramics firing, its presence in ritual context has not been previously recorded. In this paper, the anthracological record is discussed in the light of ethnographic and historic accounts. A possible explanation for the presence of bark hearths in funerary context is proposed, suggesting it might be a symbolic parallel with the quotidian: the potency and power of transformation of bark as a fuel would be regarded in a spiritual level, achieving the transformation of the body soul in the revered soul – an Ancestor.