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We report for the first time U Pb data establishing the age of the Spor Mountain Formation, a volcanic sequence that hosts the largest deposit of beryllium in the world. Determining the age of rocks hosting the beryllium deposit is critical for improved recognition of exploration targets containing additional volcanic-hosted beryllium resources. The deposit occurs in an area of extensive alkalic rhyolitic ash flow tuffs and Oligocene and Eocene calderas underlain by Paleozoic and older limestone, dolomite, shale, and quartzite. Data were obtained by analysis of zircon from the Spor Mountain Formation using the Sensitive High-Resolution Ion Microprobe-Reverse Geometry (SHRIMP-RG) technique. We show that lower fluorite and bertrandite-rich tuff and upper topaz-rich rhyolite have overlapping crystallization ages. Zircon from the crystal- and lithic-rich beryllium tuff produced two populations with a predominant group yielding a weighted average 206Pb/238U age of 25.59 + 0.29/−0.45 Ma (± 2σ errors; 41 spots that form a coherent age group) and a separate younger age group at 20.84 + 1.29/−0.64 Ma (16 spots). Spot analyses for each group include cores and rims and show no evidence for older or inherited cores.. The best estimate of the age of crystallization of the beryllium tuff is taken as 25.59 + 0.29/−0.45 Ma. Younger spot analyses that are not part of the coherent group likely reflect Pb loss from thermal events related to renewed influx of hydrothermal F-rich fluids into the tuff. Uranium concentrations and 206Pb/238U spot ages show no statistically significant correlation for the beryllium tuff. Zircon from the overlying, capping rhyolite yields weighted mean 206Pb/238U crystallization ages between ca. 25.1 Ma and 26.2 Ma. The rhyolite that yielded the slightly older age, at ca. 26.2 Ma, shows a strong positive association between U content and 206Pb/238U spot age (correlation coefficient, r = 0.88). We interpret this to be a consequence of the effects of high-U concentrations in the zircon matrix as evidenced by dark zones in crystals. Zircon temperatures from tuff range from ~600 °C to 1200 °C and in rhyolite from ~525 °C to 1000 °C. Beryllium in zircon from tuff and rhyolite overlap (~1 to 150 ppm) and do not correlate with U Pb spot age, Hf, Ti, and other trace element abundances or ratios. REE contents of zircon (chondrite-normalized) are depleted in the light REE, enriched in the heavy REE, and show prominent positive Ce and negative Eu anomalies. V-shaped REE patterns are characteristic of zircons that are not part of the coherent age group. Whole rock ratios of tuff and rhyolite, such as Th/U (>0.1) are typical of igneous zircons, plot in the field of continental settings (e.g., U/Yb ~0.8–6, Hf ~10,000–26,000), and are consistent with an origin from sources relatively enriched in Pb. The apparent uniqueness of the Spor Mountain Formation reflects the interplay of alkaline (A-type) trachytic to rhyolitic magma enriched in Be, U, Li, and F and a protracted history of fractional crystallization. Other beryllium occurrences near Spor Mountain highlight the prospective potential for additional resources of volcanic-hosted beryllium.

The REE-mineralized Khanneshin carbonatite complex in southern Afghanistan is an economically light rare earth element (LREE)-enriched carbonatite complex of Quaternary age. Geological studies have suggested that the LREE-enriched rocks at Khanneshin are comparable in grade to many economic REE deposits, including parts of the world-class Bayan Obo (China), and Mountain Pass, California (United States) deposits. The extent of mineralization at Khanneshin is unknown; however, mineralized areas delineated as part of a reconnaissance study are estimated to contain ~ 1.29 Mt REE ore. We have determined for the first time the radiogenic isotope compositions (Pb–Sr–Nd) of bulk rocks and mineral separates (barite, strontianite, carbonate, etc.) of this carbonatite complex and propose the likely source of radiogenic isotope reservoirs associated with the REE mineralization. This study provides an opportunity to establish fundamental isotopic features of this highly mineralized system to aid in regional exploration efforts and to identify other comparable mineralized systems that shared similar source reservoirs, origins, and evolution in southern Afghanistan. The carbonatite complex consists of coarse-grained sovite and brecciated and agglomeratic barite–ankerite alvikite. Small satellitic intrusions of biotite–calcite carbonatite and rare leucite phonolite also crop out. The massif is encircled by alkali metasomatized Neogene sedimentary strata. A peripheral apron of volcanic and volcaniclastic strata extends farther away from the complex. Present-day Pb isotopic compositions of bulk rocks (dikes, welded tuffs, sovite, and mineralized rocks) and mineral separates exhibit a narrow range in 206Pb/204Pb (18.814–18.877), 207Pb/204Pb (15.616–15.674), and 208Pb/204Pb (38.892–39.094). The results show that the source region of the carbonatite had a moderate compositional variation (most samples overlapping within the level of analytical precision). Present-day neodymium isotopic compositions from the Khanneshin carbonatite show a range in 143Nd/144Nd (0.512374–0.512462). Present-day strontium isotopic compositions also have a moderate range in 87Sr/86Sr (0.708034–0.709577); the mineral separates and ore are somewhat less radiogenic in 87Sr/86Sr (0.707954–0.708686) than the whole rocks. A fundamental feature of the Khanneshin carbonatite is the overall high degree of isotopic homogeneity evident for the Nd–Sr–Pb isotopic systems and we regard this consistency as a diagnostic feature related to its evolution. The carbonatite constitutes a unique isotopic target for identification of other mineralized systems that might have shared the same source. The bulk rocks and minerals in the deposit are generally analytically isotopically indistinguishable, regardless of the mineralogical complexities. All rocks and minerals shared radiogenic isotopic reservoirs, a common evolution, and have remained in isotopic equilibrium. Isotope variations eliminate the source of MORB rocks, or depleted mantle (DMM), as a significant reservoir to the Khanneshin carbonatite. Compared to model mantle reservoirs, the Pb and Nd isotopes of the Khanneshin carbonatite roughly suggest source combinations of enriched mantle, type EMI and HIMU. Sr isotopic data highlight the contribution of another source (EMII?) to account for the relatively high values of 87Sr/86Sr. The radiogenic isotope compositions of the Khanneshin carbonatite differ from world-class REE-mineralized systems such as Bayan Obo (China) and Mountain Pass (California).

Ancient man first used coal as an energy source 73,500 years ago in Les Canalettes, southern France, and archaeologists initially thought that the coal was deformed charcoal. It was used by many ancient civilizations all over the world. Coal is widely available in northern Peru and was used by ancient Peruvians, such as the Moche and Chimu, for metallurgy, mirrors, and jewelry. Algorrobo charcoal is the acknowledged fuel for metallurgy in northern Peru, but the worldwide, centuries-old use of coal, its regional availability, and its use for jewelry and mirrors in ancient Peru suggest that it may have been used for other purposes. This chapter discusses the use of coal in cremation by ancient civilizations. The Tschudi burn was an exceptionally large, single-use fire, apparently for a specific purpose or ritual, and the fuel for this event was possibly chosen for a specific characteristic such as its property as a burning rock or its sulfurous, brimstone smell. Given that mass burials are common in ancient northern Peru, 200–300 bodies were found in burial platforms at Chan Chan, and the large size of the Tschudi burn, it is possible that a number of individuals may have been cremated at the Tschudi burn. A 14C date on carbonized plant material, interpreted as tinder, indicates that the Tschudi burn was pre-European contact and took place AD 1312–1438, toward the end of Chimu domination of the region. The presence of a calcined, human skull fragment that was heated to 525°C confirms, as Colonel La Rosa said in 1877, that the site was used for burning of the dead.