@misc{langseth1977the2,
    author = "Langseth, M",
    title = "The seafloor and the Earth's heat engine",
    year = "1977",
    howpublished = "Lamont-Doherty Geological Observatory Yearbook, v. 4, p. 41-44",
    note = "talkorigins\_source = {true}; raw\_reference = {Langseth, M., 1977, The seafloor and the Earth's heat engine: Lamont-Doherty Geological Observatory Yearbook, v. 4, p. 41-44.}"
}

@article{snyder1978manganese,
    author = "Snyder, Walter S.",
    title = "Manganese deposited by submarine hot springs in chert-greenstone complexes, western United States",
    year = "1978",
    journal = "Geology",
    url = "https://doi.org/10.1130/0091-7613(1978)6<741:mdbshs>2.0.co;2",
    doi = "10.1130/0091-7613(1978)6<741:mdbshs>2.0.co;2",
    number = "12",
    openalex = "W2039713341",
    pages = "741",
    volume = "6"
}

@misc{snyder1978manganese3,
    author = "Snyder, W. S",
    title = "Manganese deposited by submarine hot springs in chert- greenstone complexes, western United States",
    year = "1978",
    howpublished = "Geology, v. 6, p. 741-744",
    note = "talkorigins\_source = {true}; raw\_reference = {Snyder, W. S., 1978, Manganese deposited by submarine hot springs in chert- greenstone complexes, western United States: Geology, v. 6, p. 741-744.}"
}

@article{bhattarai1980some,
    author = "Bhattarai, Dinesh Raj",
    title = "Some geothermal springs of Nepal",
    year = "1980",
    journal = "Tectonophysics",
    url = "https://doi.org/10.1016/0040-1951(80)90071-2",
    doi = "10.1016/0040-1951(80)90071-2",
    number = "1-2",
    openalex = "W2024167972",
    pages = "7-11",
    volume = "62",
    references = "doi101029gm008"
}

@misc{coe1981colorado,
    author = "Coe, B.A. and Zimmerman, J.",
    title = "Colorado geothermal commercialization program. Geothermal energy opportunities at four Colorado towns: Durango, Glenwood Springs, Idaho Springs, Ouray",
    year = "1981",
    url = "https://doi.org/10.2172/6636364",
    doi = "10.2172/6636364",
    openalex = "W1613410701"
}

@article{doi102113gsecongeo773519,
    author = "Crerar, David A. and Namson, Jay and Chyi, Michael So and Williams, L. A. and Feigenson, Mark D.",
    title = "Manganiferous cherts of the Franciscan assemblage; I, General geology, ancient and modern analogues, and implications for hydrothermal convection at oceanic spreading centers",
    year = "1982",
    journal = "Economic Geology",
    abstract = "There are several hundred ophiolitic manganiferous chert deposits, primarily of late Jurassic to early Cretaceous age, known within the Franciscan assemblage of California. The sequences typically consist of one to three massive, manganiferous chert lenses containing 30 to 50 percent Mn, and averaging 1 m in thickness by 15 m subcircular diameter; these are separated by an average 2 to 10 m of thin-bedded radiolarian cherts and overlie basalts or greenstones. Both their geology and chemistry indicate that the ore lenses are hydrothermal and may have formed on the flanks of a mid-ocean ridge or within a back-arc basin. It is proposed that the sequences developed as a result of sea-floor spreading over a series of deep hydrothermal seawater convection cells paralleling a spreading center and spaced roughly 5 to 10 km apart. Chemical profiles of Mn, Fe, Si, Al, Cu, Ni, Zn, Co, Ba, Ti, the rare earth elements, and 87 Sr/ 86 Sr have been determined through two complete sections. These profiles indicate hydrothermal input of Mn, Si, Cu, Ni, Zn, and Ba and detrital or hydrogenous input of Al and Co; they illustrate the use of Ti as a measure of relative detrital sedimentation rates. Fe is strongly fractionated from Mn within the ores (Fe/Mn < 0.1), and Fe/Mn ratios decrease upward throughout each section suggesting preferential deposition of Fe within the sediment, and of Mn at the seawater interface. Rare earth element distributions reflect the interaction of sea-water and underlying basalts. Sr isotopic ratios of the ores and basalts demonstrate both strong and moderate seawater influences, respectively. Fluid inclusion analyses on veins of undetermined age show seawater salinity, temperatures of roughly 200 degrees C, and tentative entrapment pressures corresponding to 1,700-m water depth. Early and intermediate veins were injected into unconsolidated siliceous sediment producing a characteristic bleached and pseudobrecciated texture. An analogy is drawn with the present-day field of hydrothermal mounds near the Galapagos rift and with ophiolitic complexes of the northern Apennines and other localities.",
    url = "https://doi.org/10.2113/gsecongeo.77.3.519",
    doi = "10.2113/gsecongeo.77.3.519",
    openalex = "W2124648655"
}

@misc{edmond1983hot1,
    author = "Edmond, J. M. and Von Damm, K",
    title = "Hot springs on the ocean floor",
    year = "1983",
    howpublished = "Scientific American, v. 248, no. 4, p. 78-93",
    note = "talkorigins\_source = {true}; raw\_reference = {Edmond, J. M., and Von Damm, K., 1983, Hot springs on the ocean floor: Scientific American, v. 248, no. 4, p. 78-93.}"
}

@article{doi101111j17513928200800072x,
    author = "Moriyama, T. and Panigrahi, Mruganka K. and Pandit, Dinesh and Watanabe, Yasushi",
    title = "Rare Earth Element Enrichment in Late Archean Manganese Deposits from the Iron Ore Group, East India",
    year = "2008",
    journal = "Resource Geology",
    abstract = "Abstract The major, trace and rare earth element (REE) composition of Late Archean manganese, ferromanganese and iron ores from the Iron Ore Group (IOG) in Orissa, east India, was examined. Manganese deposits, occurring above the iron formations of the IOG, display massive, rhythmically laminated or botryoidal textures. The ores are composed primarily of iron and manganese, and are low in other major and trace elements such as SiO 2, Al 2 O 3, P 2 O 5 and Zr. The total REE concentration is as high as 975 ppm in manganese ores, whereas concentrations as high as 345 ppm and 211 ppm are found in ferromanganese and iron ores, respectively. Heavy REE (HREE) enrichments, negative Ce anomalies and positive Eu anomalies were observed in post‐Archean average shale (PAAS)‐normalized REE patterns of the IOG manganese and ferromanganese ores. The stratiform or stratabound shapes of ore bodies within the shale horizon, and REE geochemistry, suggest that the manganese and ferromanganese ores of the IOG were formed by iron and/or manganese precipitation from a submarine, hydrothermal solution under oxic conditions that occurred as a result of mixing with oxic seawater. While HREE concentrations in the Late Archean manganese and ferromanganese ores in the IOG are slightly less than those of the Phanerozoic ferromanganese ores in Japan, HREE resources in the IOG manganese deposits appear to be two orders of magnitude higher because of the large size of the deposits. Although a reliable, economic concentration technique for HREE from manganese and ferromanganese ores has not yet been developed, those ores could be an important future source of HREE.",
    url = "https://doi.org/10.1111/j.1751-3928.2008.00072.x",
    doi = "10.1111/j.1751-3928.2008.00072.x",
    openalex = "W1996917932",
    references = "doi1011456shigenchishitsu195140159"
}

@article{doi101111j13653091201001165x,
    author = "Behl, Richard J.",
    title = "Chert spheroids of the Monterey Formation, California (USA): early‐diagenetic structures of bedded siliceous deposits",
    year = "2010",
    journal = "Sedimentology",
    abstract = "Abstract Chert spheroids are distinctive, early‐diagenetic features that occur in bedded siliceous deposits spanning the Phanerozoic. These features are distinct in structure and genesis from similar, concentrically banded ‘wood‐grain’ or ‘onion‐skin’ chert nodules from carbonate successions. In the Miocene Monterey Formation of California (USA), chert spheroids are irregular, concentrically banded nodules, which formed by a unique version of brittle differential compaction that results from the contrasting physical properties of chert and diatomite. During shortening, there is brittle fracture of diatomite around, and horizontally away from, the convex surface of strain‐resistant chert nodules. Unlike most older siliceous deposits, the Monterey Formation still preserves all stages of silica diagenesis, thus retaining textural, mineralogical and geochemical features key to unravelling the origin of chert spheroids and other enigmatic chert structures. Chert spheroids found in opal‐A diatomite form individual nodules composed of alternating bands of impure opal‐CT chert and pure opal‐CT or chalcedony. With increased burial diagenesis, surrounding diatomite transforms to bedded porcelanite or chert, and spheroids no longer form discrete nodules, yet still display characteristic concentric bands of pure and impure microcrystalline quartz and chalcedony. Petrographic observations show that the purer silica bands are composed of void‐filling cement that precipitated in curved dilational fractures, and do not reflect geochemical growth‐banding in the manner of Liesegang phenomena invoked to explain concentrically banded chert nodules in limestone. Chertification of bedded siliceous sediment can occur more shallowly (< 100 m) and rapidly (< 1 Myr) than the bulk silica phase transitions forming porcelanite or siliceous shale in the Monterey Formation and other hemipelagic/pelagic siliceous deposits. Early diagenesis is indicated by physical properties, deformational style and oxygen‐isotopic composition of chert spheroids. Early‐formed cherts formed by pore‐filling impregnation of the purest primary diatomaceous beds, along permeable fractures and in calcareous–siliceous strata.",
    url = "https://doi.org/10.1111/j.1365-3091.2010.01165.x",
    doi = "10.1111/j.1365-3091.2010.01165.x",
    openalex = "W1927566449",
    references = "doi1010160191814187901179"
}

@incollection{crossref2014sources,
    title = "Sources of Geothermal Heat: The Earth as a Heat Engine",
    year = "2014",
    booktitle = "Geothermal Energy",
    url = "https://doi.org/10.1201/b17521-9",
    doi = "10.1201/b17521-9",
    openalex = "W2484340266",
    pages = "42-67",
    references = "doi101006icar20016639, doi101007bf02202896, doi101016jrser201405032, doi101029138gm06, doi10102993jb02222, doi101029rf003p0105, doi101038nature00982, doi101038nature00995, doi101146annurevea18050190001225, doi101146annurevearth241191"
}

@article{shakeri2015rare,
    author = "Shakeri, Ata and Ghoreyshinia, Sayedkazem and Mehrabi, Behzad and Delavari, Morteza",
    title = "Rare earth elements geochemistry in springs from Taftan geothermal area SE Iran",
    year = "2015",
    journal = "Journal of Volcanology and Geothermal Research",
    url = "https://doi.org/10.1016/j.jvolgeores.2015.07.023",
    doi = "10.1016/j.jvolgeores.2015.07.023",
    openalex = "W1172788097",
    pages = "49-61",
    volume = "304",
    references = "doi101016000925419090080q, doi1010160016703770901109, doi1010160016703781901150, doi1010160016703788901433, doi101016001670379090432k, doi101016001670379290334f, doi101016001670379500314p, doi101016s0009254198001429, doi101139e81019, doi101144gslsp19890420119"
}

@article{doi101016jjasrep201611015,
    author = "Skarpelis, Nikolaos and Carter, Tristan and Contreras, Daniel A. and Mihailović, Danica D.",
    title = "Characterization of the siliceous rocks at Stélida, an early prehistoric lithic quarry (Northwest Naxos, Greece), by petrography and geochemistry: A first step towards chert sourcing",
    year = "2017",
    journal = "Journal of Archaeological Science Reports",
    url = "https://doi.org/10.1016/j.jasrep.2016.11.015",
    doi = "10.1016/j.jasrep.2016.11.015",
    openalex = "W2576340679",
    references = "doi1010160016703784902989, doi1010160037073894900396, doi1010160305748884902007, doi101016jcsr200811005, doi101017s0003598x00083733, doi10102993tc01131, doi10108009853111199411105259, doi101111j1751908x1995tb00147x, doi101126science1543748507, doi1015159781501509032010"
}

@article{doi101021acsest9b00301,
    author = "Brewer, Aaron and Chang, Elliot and Park, Dan and Kou, Tianyi and Li, Yat and Lammers, Laura N. and Jiao, Yongqin",
    title = "Recovery of Rare Earth Elements from Geothermal Fluids through Bacterial Cell Surface Adsorption",
    year = "2019",
    journal = "Environmental Science \& Technology",
    abstract = "The increasing demand for rare earth elements (REEs) in the modern economy motivates the development of novel strategies for cost-effective REE recovery from nontraditional feedstocks. We previously engineered E. coli to express lanthanide binding tags on the cell surface, which increased the REE biosorption capacity and selectivity. Here we examined how REE adsorption by the engineered E. coli is affected by various geochemical factors relevant to geothermal fluids, including total dissolved solids (TDS), temperature, pH, and the presence of specific competing metals. REE biosorption is robust to TDS, with high REE recovery efficiency and selectivity observed with TDS as high as 165,000 ppm. Among several metals tested, U, Al, and Pb were found to be the most competitive, causing >25\% reduction in REE biosorption when present at concentrations ∼3- to 11-fold higher than the REEs. Optimal REE biosorption occurred between pH 5-6, and sorption capacity was reduced by ∼65\% at pH 2. REE recovery efficiency and selectivity increased as a function of temperature up to ∼70 °C due to the thermodynamic properties of metal complexation on the bacterial surface. Together, these data define the optimal and boundary conditions for biosorption and demonstrate its potential utility for selective REE recovery from geofluids.",
    url = "https://doi.org/10.1021/acs.est.9b00301",
    doi = "10.1021/acs.est.9b00301",
    openalex = "W2952676252",
    references = "doi1010160016703789900173, doi101016jcej201603082, doi101016jchemgeo200502009, doi101016jcopbio201503019, doi101016jjhazmat200803038, doi101016jmineng201310021, doi101016jmineng201503012, doi101016s1369703x00000838, doi101039c4gc02483d, doi103390min7110203, shakeri2015rare"
}

@incollection{crossref2023contracting,
    title = "Contracting for Geothermal in Hot Springs",
    year = "2023",
    booktitle = "Contracting in Japan",
    url = "https://doi.org/10.1017/9781009215763.004",
    doi = "10.1017/9781009215763.004",
    openalex = "W4385687636",
    pages = "91-115"
}

@inproceedings{andpepin2024characterizing,
    author = "Pepin, Jeffrey and Newman, Connor and Hall, Nicholas G. and Palko, Kelli M. and Russell, Cory A. and Flynn, Robert H.",
    title = "CHARACTERIZING THE STEAMBOAT SPRINGS, COLORADO, HOT-SPRINGS GEOTHERMAL RESOURCE",
    year = "2024",
    booktitle = "Geological Society of America Abstracts with Programs",
    url = "https://doi.org/10.1130/abs/2024cd-399534",
    doi = "10.1130/abs/2024cd-399534",
    openalex = "W4403449404"
}

@inproceedings{andge2025geothermal,
    author = "Ge, Shemin and Roseanna, Neupauer",
    title = "Geothermal Energy Extraction and Thermal Springs",
    year = "2025",
    booktitle = "Geological Society of America Abstracts with Programs",
    url = "https://doi.org/10.1130/abs/2025am-7044",
    doi = "10.1130/abs/2025am-7044",
    openalex = "W4417219357"
}

@article{doi101016jgexplo2025107845,
    author = "Russo, Samantha and González-Álvarez, Ignacio and Cocker, Helen A. and McCoy‐West, Alex J.",
    title = "The fundamentals of rare earth element ion adsorption clay deposits: A mineral systems approach for exploration",
    year = "2025",
    journal = "Journal of Geochemical Exploration",
    abstract = "The exponential growth of demand for ‘green-technologies’ requires significantly increased production of critical elements, including rare earth elements (REE). Some of the most significant (and largest) REE deposits are associated with carbonatites. However, carbonatites are predominantly light-(L)REE-enriched, which has implications for meeting global heavy-(H)REE demand. As a result, REE ion adsorption clay deposits (IACD), which are examples of intense weathering, have sparked international interest as a HREE source (\textasciitilde 80 \% of global HREE are sourced from IACD). Therefore, this study presents a comprehensive review of REE IACD to understand their constraints, global distribution, and main features while applying a mineral systems approach. The REE source for IACD, although typically granitic, is more diverse than traditionally thought, with the weathering of local igneous, metamorphic, and sedimentary rocks and external fluids (e.g., hydrothermal fluids and basinal brines) and lithologies (e.g., transport of weathering constituents rather than an in-situ source) supplying the REE required for IACD formation. Following the weathering of REE-rich source material, REE are liberated and mobilised in the weathering profile through pH dependent complexation with ligands (e.g., F −, CO 3 2−, SO 4 2−, PO 4 3−) or as hydrated REE species. The nature of the source (e.g., relative LREE- or HREE-enrichment) and fluids within the weathering profile (e.g., pH and ligand concentrations) control REE fractionation and relative LREE and HREE enrichment of a IACD. Once mobilised, REE are adsorbed out of solution and enriched onto clay minerals (e.g., kaolinite and halloysite), a process strongly controlled by pH and the physicochemical characteristics of the clays present, with REE adsorption most favourable under circumneutral conditions. To preserve REE enrichment (and IACD formation) through clay adsorption, a low erosional setting is required. Climates with excessive rainfall (e.g., tropical humid climates) may be problematic for REE IACD preservation through geological time, where excessive rainfall results in clay dissolution and saprolite collapse. The conceptual model provided in this study develops a framework that will be built upon in the coming years as our knowledge of these deposit types and global exploration continues. • Investigating the source, mobilisation, adsorption, and preservation of REE IACD • The REE source for REE IACD is more diverse than originally thought. • pH strongly controls relative LREE- and HREE-enrichment in the weathering profile. • Rare earth element adsorption is strongly controlled by clay minerals and pH.",
    url = "https://doi.org/10.1016/j.gexplo.2025.107845",
    doi = "10.1016/j.gexplo.2025.107845",
    openalex = "W4411251229",
    references = "doi101086628474, shakeri2015rare"
}

@article{doi101016joregeorev2025106661,
    author = "Azami, Keishiro and Fujinaga, Koichiro and Hirano, Naoto and Kato, Yasuhiro",
    title = "Origin of ferromanganese deposits in the Jurassic to Cretaceous accretionary complex: Implications for the deep-sea environment around ocean anoxic events",
    year = "2025",
    journal = "Ore Geology Reviews",
    abstract = "• Fe deposits in the Tokoro Belt formed at a mid-ocean ridge (MOR) at ∼ 161.5–165.3 Ma. • In contrast, Mn deposits formed at an oceanic island around 120 Ma. • MOR volcanism was already active before rapid global warming in the Oxfordian. • The deep sea in pelagic regions was oxic throughout oceanic anoxic event 1a. In the Tokoro Belt, which is a Jurassic to Cretaceous accretionary complex in Japan, Fe and Mn deposits are distributed along basaltic rocks and chert. This study proposes the origin of these Fe and Mn deposits and reconstructs marine Os isotope ratios. The samples were found to exhibit negative Ce anomalies and low transition metal contents other than Fe and Mn, which are typical of submarine hydrothermal ferromanganese oxides. The Fe deposit samples were enriched in rare-earth elements due to apatite accumulation. Several Mn deposit samples showed positive Eu anomalies, suggesting high-temperature water–rock interactions. The radiolarian ages of red cherts in previous studies and the distributions of mid-ocean ridge (MOR) and oceanic island basalts indicate that Fe deposits were formed by hydrothermal activity at an MOR in the Callovian or older. In contrast, Mn deposits were formed by hydrothermal activity on oceanic islands approximately 5 × 10 3 km from the MOR at approximately 120 Ma. The low initial Os isotope ratios of the Fe deposit samples (0.411–0.445) suggest that volcanism in the MOR was active before the Late Jurassic oceanic anoxic event (OAE). The initial Os isotope ratios of the Mn deposit samples from the western and southern sections correspond to the marine Os isotope ratios observed before and during OAE1a (∼124–119.55 Ma and 119.5–118.5 Ma, respectively). As the Mn deposits are interbedded with red chert, it can be inferred that an oxic environment was maintained in the deep-sea pelagic regions throughout OAE1a.",
    url = "https://doi.org/10.1016/j.oregeorev.2025.106661",
    doi = "10.1016/j.oregeorev.2025.106661",
    openalex = "W4410137748",
    references = "doi1011456shigenchishitsu195140159"
}