Alterations in the tissue microenvironment collaborate with cell autonomous genetic changes to contribute to neoplastic progression. The importance of the microenvironment in neoplastic progression is underscored by studies showing that fibroblasts isolated from a tumor stimulate the growth of preneoplastic and neoplastic cells in xenograft models. Similarly, senescent fibroblasts promote preneoplastic cell growth in vitro and in vivo. Because senescent cells accumulate with age, their presence is hypothesized to facilitate preneoplastic cell growth and tumor formation in older individuals. To identify senescent stromal factors directly responsible for stimulating preneoplastic cell growth, we carried out whole-genome transcriptional profiling and compared senescent fibroblasts with their younger counterparts. We identified osteopontin (OPN) as one of the most highly elevated transcripts in senescent fibroblasts. Importantly, reduction of OPN protein levels by RNA interference did not affect senescence induction in fibroblasts; however, it dramatically reduced the growth-promoting activities of senescent fibroblasts in vitro and in vivo, showing that OPN is necessary for paracrine stimulation of preneoplastic cell growth. In addition, we found that recombinant OPN was sufficient to stimulate preneoplastic cell growth. Finally, we show that OPN is expressed in senescent stroma within preneoplastic lesions that arise following 7,12-dimethylbenz(a)anthracene/12-O-tetradecanoylphorbol-13-acetate treatment of mice, suggesting that stromal-derived OPN-mediated signaling events affect neoplastic progression. [Cancer Res 2009;69(3):1230-9]

In the field, pumice clasts were taken from four unconsolidated ignimbrite deposits and a welded tuff in the Roseau Valley (Fig. DR1). The sample location distribution was controlled by exposures, often limited to road cuts, but spans the length of the Roseau Valley. The most distal sample was from a 20 m thick deposit in the city's Botanical Gardens (King's Hill), not previously documented, ~8 km from the summit of Micotrin. The basal St. Aromont sample is from a 50 m thick pyroclastic sequence previously described by Howe et al. (2014) as part of the Link Flow sequence, ~8 km from Micotrin. The Casso sample was located on the southern ridge flank of the Roseau River, 6 km from Micotrin at an elevation of 250 m. The Casso deposit is a ~15 m thick pyroclastic deposit, dominated by ash and has not previously been studied. The Trafalgar sample was from a 2 m boulder of welded tuff at the base of Trafalgar Falls, a ~200 m thick sequence, which is the most proximal deposit to the proposed vent, ~2 km from Micotrin.

The Quaternary Big Pine (BP) volcanic field in eastern California is notable for the occurrence of mantle xenoliths in several flows. This points to rapid ascent of basalt through the crust and precludes prolonged storage in a crustal reservoir. In this study, the hypothesis of phenocryst growth during ascent is tested for several basalts (13-7 wt% MgO) and shown to be viable. Phenocrysts of olivine and clinopyroxene frequently display diffusion-limited growth textures, and clinopyroxene compositions are consistent with polybaric crystallization. When the most Mg-rich olivine in each sample is paired with the whole-rock composition, resulting Fe 2 þ-Mg K D (olivine-melt) values (0.31-0.36) match those calculated from literature models (0.32-0.36). Application of a Mg-and a Ni-based olivine-melt thermometer from the literature, both calibrated on the same experimental data set, leads to two sets of temperatures that vary linearly with whole-rock MgO wt%. Because the Ni thermometer is independent of water content, it provides the actual temperature at the onset of olivine crystallization (1247-1097°C), whereas the Mg thermometer gives the temperature under anhydrous conditions and thus allows ΔT (=T Mg − T Ni = depression of liquidus due to water) to be obtained. The average ΔT for all samples is~59°C, which is consistent with analyzed water contents of 1.5-3.0 wt% in olivine-hosted melt inclusions from the literature. Because the application of olivine-melt thermometry/hygrometry at the liquidus only requires microprobe analyses of olivine combined with whole-rock compositions, it can be used to obtain large global data sets of the temperature and water contents of basalts from different tectonic settings. Plain Language Summary Basaltic lavas are a window into their mantle source regions, which is why it is important to determine their temperatures and water contents. In this study, a new approach that allows these two parameters to be quantified is demonstrated for basalts from the Big Pine volcanic field, CA. They were targeted because many contain chunks of dense mantle rocks, which precludes storage in a crustal magma chamber and points to direct ascent from the mantle to the surface along fractures. Two hypotheses are proposed, tested, and shown to be viable in this study: (1) olivine crystallized in the basalts during ascent, and (2) the most Mg-rich olivine analyzed in each basalt represents the first olivine to grow during ascent. This enables the most Mg-rich olivine to be paired with the whole-rock composition in the application of olivine-melt thermometry and hygrometry. The results match those from published, independent studies. The success of this approach paves the way for the attainment of large, high-quality data sets for basalts from a wide variety of tectonic settings. This, in turn, may allow global variations in mantle temperature and volatile content to be mapped in greater detail and better understood.

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<p>Figure S1: Geologic maps of (a) Marl Mountain Quadrangle presented by Wilshire et al. (2002b) and (b). Figure S2: Peridotite mantle xenoliths found in Cima-4a and −4b, and DH-1. Figure S3: Histogram of Fo mol% ( = XMgO/(XMgO + XFeO) × 100) for Cima-4a. Figure S4: Representative BSE images of clinopyroxene phenocrysts from each textural category including (1) non-spongy/non-vermicular (2) spongy/vermicular and (3) oscillatory/sector-zoned. Figure S5: Histograms of clinopyroxene Mg# for five Cima hawaiites. Figure S6: Plots of Na2O, TiO2, and Cr2O3 (wt%) versus Mg# from analyzed clinopyroxene phenocrysts. Figure S7: Histograms of anorthite content (An mol% = XCaO/XCaO + XNa2O + XK2O) × 100) for three Cima basalts. Table S1: Standards employed for electron microprobe analyses of olivine, clinopyroxene, plagioclase, and Fe-Ti oxides. Table S2: Analyzed trace-element concentrations for all Cima samples. Table S3: Olivine phenocryst analyses for all Cima and Dish Hill samples. Table S4: (A) Clinopyroxene analyses for five Cima hawaiites. (B) Composition of the most Mg-rich clinopyroxene phenocryst. Table S5: (A) Microprobe analyses of ilmenite and titanomagnetite from six Cima hawaiites. (B) Fe-Ti oxide thermometry and oxybarometry (Ghiorso and Evans, 2008) results for all possible pairs of ilmenite and titanomagnetite. (C) Composition (wt%) of onset ilmenite and titanomagnetite pair that pass the Bacon and Hirschmann (1988) test for equilibrium. Table S6: (A) Plagioclase phenocryst analyses for three Cima hawaiites. (B) Analysis of most calcic plagioclase phenocryst. Table S7: Olivine-melt thermometry applied to all Cima and Dish Hill samples. </p>

The Cima volcanic field, in the southern Basin and Range province (California, USA), includes &gt;70 eruptive units over the last 8 m.y. The youngest (≤1 Ma) are low Mg# (≥56) hawaiites derived from an asthenospheric mantle source. The Cima hawaiites, and adjacent Dish Hill basanites, are known for carrying large mantle xenoliths, which precludes stalling in a crustal reservoir. This raises the question of how low Mg# hawaiites, which cannot be in equilibrium with peridotite mantle, formed and differentiated while carrying dense, mantle xenoliths. Several hypotheses are evaluated and the only one shown to be viable is mixing between high-MgO basanite (with entrained mantle xenoliths and sparse olivine phenocrysts) and low-MgO mugearite liquids, which formed by partial melting of mafic lower crust under relatively dry and reducing conditions. Multiple lines of evidence, including the presence of mantle xenoliths in hawaiites, diffusion-limited growth textures in olivine and clinopyroxene, and notably thin Fe-rich rims on high-MgO olivine crystals (inherited), indicate magma mixing must have occurred rapidly (days or less) during ascent to the surface along intersecting fractures, and not in a stalled crustal reservoir. Abundant evidence points to clinopyroxene growth immediately after mixing, and application of clinopyroxene-melt barometry constrains the depth of mixing to the lower and middle crust (0.8–0.4 GPa). Results from olivinemelt thermometry/hygrometry (~1196 °C and ~1.4 wt% H2O) applied to a basanite from Dish Hill carrying 5–20 cm mantle xenoliths leads to calculated ascent velocities ≥0.3–4.9 km/h, enabling ascent through the 36 km thick crust in ≤7–119 h.

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