The Condrey Mountain Schist occupies a window through Late Triassic(?) amphibolite facies mélange of the Western Paleozoic and Triassic Belt in the north centralKlamath Mountains. Along the western margin of the window, the schist comprises a sequence of multiply deformed, greenschist facies metavolcanic and fine-grained metasedimentary rocks, which are in thrust or high-angle fault contact with graphite-quartzmica schist exposed in the window interior. Transitional blueschist-greenschist facies parageneses are developed in metabasites, metacherts, and metalliferous metasedimentary rocks in the graphitic schist in the central part of the window. All units record progressive, polyphase, deformational and metamorphic histories.The earliest stages of deformation in the blueschists generated isoclinal intrafolial folds (Fi), a layer-parallel transposition foliation, and a strong crossite lineation. The foliation is folded by two later sets of coaxial, isoclinal to tight folds (F2 and F3) that produce kilometer-scale, N-S trending, recumbent folds in the central part of the window. The same deformational sequence is recorded in the graphitic schist by continued regeneration of the transposition foliation through at least the second set of folds, and tight to isoclinal folding of the resulting surfaces. Both lithologies have been further deformed by extension parallel to F3 axes (boudinage and fracturing) and a late folding (F4) that produced kink bands, box folds, and chevron folds with E-W trending axes. Fold styles and asymmetries suggest that the early stages of progressive deformation (Fi folding, transposition) resulted from noncoaxial deformation. Shear strains diminish during F2 and F3 folding and are replaced by irrotational flattening strains by the time of boudinage.The mineral assemblages formed prior to F2 folding indicate greenschist-blueschist facies conditions during transposition. F2 and F3 folding were accompanied by the growth of deerite that lies in the axial planes of minor folds in meta-ironstones, indicating P-T conditions similar to those existent during transposition. Boudinage is concurrent with and followed by the static growth of chlorite, actinolite, albite, stilpnomelane, spessartine, and the Ba-silicate, cymrite. Ferroglaucophane rims on crossite may also have grown at this time. Pressure and temperature estimates, the relative time framework of deformational events, and the noncoaxial geometry of ductile strain are all consistent with, but not restricted to, a subduction zone environment. High shear strains may reflect descent and burial, whereas flattening and static mineral growth occur during uplift. Regional relationships favor an interpretation that relates metamorphism and ductile deformation to a Middle Jurassic subduction event, but do not preclude a Late Jurassic age for deformation and metamorphism. on July 3, 2015 memoirs.gsapubs.org Downloaded from *MV = metavolcanic; P = pelite; MC = metachert; GS = graphitic schist; CS = chloritic schist; MMS = metalliferous metasediment. *...

Monumental architecture is a prime indicator of social complexity, because it requires many people to build a conspicuous structure commemorating shared beliefs. Examining monumentality in different environmental and economic settings can reveal diverse reasons for people to form larger social units and express unity through architectural display. In multiple areas of Africa, monumentality developed as mobile herders created large cemeteries and practiced other forms of commemoration. The motives for such behavior in sparsely populated, unpredictable landscapes may differ from well-studied cases of monumentality in predictable environments with sedentary populations. Here we report excavations and ground-penetrating radar surveys at the earliest and most massive monumental site in eastern Africa. Lothagam North Pillar Site was a communal cemetery near Lake Turkana (northwest Kenya) constructed 5,000 years ago by eastern Africa's earliest pastoralists. Inside a platform ringed by boulders, a 119.5-m mortuary cavity accommodated an estimated minimum of 580 individuals. People of diverse ages and both sexes were buried, and ornaments accompanied most individuals. There is no evidence for social stratification. The uncertainties of living on a "moving frontier" of early herding-exacerbated by dramatic environmental shifts-may have spurred people to strengthen social networks that could provide information and assistance. Lothagam North Pillar Site would have served as both an arena for interaction and a tangible reminder of shared identity.

fossil subduction interface records distributed de-10 formation across a 2+ km dominantly sedimentary shear zone. 11 • Subduction erosion of the overriding plate sourced ultramafic lenses, which were 12 subsequently entrained and underplated at depth. 13 • Periodic strain localization to the margins of km-scale ultramafic lenses facilitated 14 decoupling from the downgoing slab and underplating.

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We are studying how "robotic follow-up" can improve future planetary exploration. Robotic follow-up, which we define as augmenting human field work with subsequent robot activity, is a field exploration technique designed to increase human productivity and science return. To better understand the benefits, requirements, limitations and risks associated with this technique, we are conducting analog field tests with human and robot teams at the Haughton Crater impact structure on Devon Island, Canada. In this paper, we discuss the motivation for robotic follow-up, describe the scientific context and system design for our work, and present results and lessons learned from field testing.