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The Sara-Fier complex is composed mainly of granites, but also includes minor acid volcanic rocks and a few small intrusions of basic and intermediate composition. The acid intrusive rocks of the complex form five distinct ring-centres which overlap in a north-south line. An ideal order of events in these ring-centres, applicable to the Nigerian Younger Granite province as a whole is: (i) early volcanic rocks, mainly rhyolitic; (2) ring-fracture, cauldron-subsidence, and the intrusion of a ring-dyke, often of hornblende-granite-porphyry or horn-blende-pyroxene-fayalite-granite; (3) the emplacement of a succession of granites within this ring-fault, generally in a concentric fashion, and including hornblende-biotite-, biotite-, and riebeckite-granites. Intrusive activity seems normally to have been confined within the outer ring-dyke and to have been completed in each centre before the beginning of a new centre. The early ring-dykes are steep structures and since they may be up to a mile wide their emplacement cannot be explained by simple cauldron-subsidence. Later ring-dyke-like bodies and stocks do, however, show outward-dipping contacts, and their emplacement seems to have been controlled by underground cauldron-subsidence beneath dome-shaped fractures.

The authors theorize what we call managerialist subterfuge, drawing on distinct ethnographic studies to examine how adult “partners” leverage the language and strategies of corporate managerialism to undermine youths’ radical visions of change. Critical analysis of patterns in interview and participant observation data across two youth participatory action research projects revealed the ways in which adult interventions functioned to co-opt youths’ activist agendas; following the rationale that youth who are presumed to be in need of adult management are “out of their depth” when it comes to civic matters. The authors assert that managerialist subterfuge functions as a mechanism to further bureaucratize youth activism and absolve state actors of accountability for harm that Black youth and youth of color experience.

A series of overlapping ring structures each contain varied, pre-caldera volcanic sequences, overlain by massive intra-caldera rhyolitic ignimbrites and enclosed within ring dykes of fayalite-hedenbergite granite-porphyry. Early basalts are hypersthene-normative but may originally have been alkaline or transitional to nepheline-normative. They are linked, through a series of andesine basalts, mugearites and trachyandesites, to aphyric trachytes. Pre-caldera rhyolitic rocks, interbedded with and overlying the basic and intermediate volcanics, are mainly ignimbrites which were perhaps originally peralkaline or near peralkaline, but are often recrystallized to subalkaline compositions. They formed mainly through partial melting with zone refining of crustal rocks, the mantle-derived basic to intermediate magmas providing the heat source. In the early stages of each caldera-forming cycle the ignimbrite eruptions were of small volume and the rocks have varied crystal contents. Later, large high level magma chambers must have developed, from which crystal-rich ignimbrites with volumes in the order of 100 km 3 were erupted, with accompanying caldera collapse. The form of the complex as a whole shows that this cycle occurred repeatedly, but with the location of magma generation migrating progressively westwards, resulting in a chain of rhyolitic cauldrons, into which subvolcanic granites and syenites have been emplaced.