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We are grateful to Mr. Bryan Yap, President of Lepanto Consolidated Mining Company, for permission to conduct this study in the Mankayan district, for providing access to the air magnetic and radiometric survey results, and for permission to publish the outcome of this study. This work is part of AMIRA Project P765, completed in December, 2006, at CODES, University of Tasmania. The project was sponsored by Anglo American, Anglo Gold Ashanti, Gold Fields, Newcrest, Newmont, Placer Dome, and Teck Cominco, as well as Barrick in the final year, with additional funding provided by the Australian Research Council. We acknowledge the discussion and ideas provided by representatives of the sponsoring companies, and assistance by the AMIRA research coordinator Alan Goode. We thank Lyndon Bradish and Froilan Conde, plus many other Lepanto staff, including Bene, Danny, Ed, Louie, Perfecto, Perry, Ric, and Willy, for their assistance, and Dave Braxton for help in the field. Paddy Waters of Anglo American Philippines generously provided logistic support and funding for some of the whole-rock geochemical analyses. We appreciate the help from CODES staff, including Simon Stephens for sample preparation, Sarah Gilbert and Leonid Danyushevsky for LA-ICP-MS analyses, and June Pongratz for report preparation. We thank Roger Stoffregen for comments on an early version of the manuscript, and John Thompson and Raymond Jannas for useful reviews.

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2A and 3). Nevertheless, in both environments there was no relation between ability to diversify and time spent evolving in the original high-nutrient media (Fig. 3) (sign tests of correlations between number of genotypes and transfer number for the six lines: P Ͼ 0.2 in both cases). Adaptation can limit the ability of bacterial genotypes to diversify genetically. This was not the result of generalist evolution or the evolution of an intrinsic reduction in evolvability, but was caused by environment-specific adaptation. Given the strong empirical support for both the importance of environmental heterogeneity in diversification (7-14) and epistasis (6, 24), it is likely that rugged fitness landscapes, a requirement for the observed effects, are common. These results are therefore likely to be generally relevant and may help to explain patterns of diversity over both micro-and macroevolutionary time scales. Consistent with recent interpretations of macroevolutionary adaptive radiations (25), we predict that in environments that can potentially support similar levels of diversity, diversification is more likely to occur immediately following colonization of the environment than through expansion into new niches within the environment after an extinction event. 25. D. Schluter, The Ecology of Adaptive Radiations (Oxford Univ. Press, Oxford, 2000). 26. We thank L. Hurst and three anonymous referees for comments on the manuscript. This work was funded by the Royal Society and Natural Environment Research Council (UK).

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The Beiya skarn gold deposit is located in the eastern Tethyan orogenic belt in western Yunnan province, China. It is one of the largest gold deposits in China, with significant amounts of silver and base metals. To the end of 2014, the estimated resources are 125 million tonnes (Mt) of ore, grading 2.42 g/t Au, 0.48 wt % Cu, 25.5 wt % Fe, 38.85 g/t Ag, 1.24 wt % Pb, and 0.53 wt % Zn. Skarn alteration and mineralization are related to shoshonitic quartz monzonite porphyries that were emplaced in Triassic carbonates (Beiya Formation). Re-Os dating on molybdenite from a skarn orebody indicates an ore-forming age of 36.82 ± 0.48 Ma, which is consistent with previous dating results of the quartz monzonite porphyries. At least two paragenetic stages of skarn minerals and associated sulfides were recognized, with the early stage typified by garnet ± pyroxene, magnetite, and calcite, and the late stage characterized by epidote, amphibole, chlorite, quartz, and calcite, containing up to 70% sulfides (pyrite, chalcopyrite, and minor pyrrhotite). The early skarn is dominated by anhydrous minerals, which were replaced by hydrous minerals formed during the late stage. The garnet in the Beiya deposit is andradite rich (Ad36-97Gr3-61), and pyroxene is relatively diopside rich (Di8-91Hd7-89). This mineral assemblage indicates an oxidized skarn system, similar to other Au-Cu, Fe-bearing skarn deposits around the world. Fluid inclusions from pyroxene indicate precipitation from high-temperature and high-to moderate-salinity fluids (420°-530°C, 11.1-43.3 wt % NaCl equiv), which probably results from boiling of a moderately saline magmatic fluid. Cooler (180°-365°C) and moderate-to low-salinity fluids (1.6-16.5 wt % NaCl equiv) were trapped in garnet and quartz and are interpreted to be responsible for gold deposition. Chlorite chemistry indicates ore-forming temperatures between 300° and 340°C, in agreement with fluid inclusion data. It appears that gold was transported as chloride complexes under oxidized conditions and was deposited at temperatures of about 300°C, when transport of chloride complexes as gold carriers was less efficient.