Obsidian Sourcing and Hydration
Obsidian Sources in Baja California
| Source: Lágrimas de Apache Location: Near the mouth of the Colorado River Chemical Characterization: Panich et al. 2012; Panich, Michelini, and Shackley 2013 Archaeological Occurrences: El Mayor Other References: Panich, Michelini, Bendímez, and Shackley 2013; Téllez et al. 2013 Comments: This material occurs in small nodules measuring 2-5 cm; its prehistoric use may have been extremely limited. |
| Source: Unknown (Santa Catarina) Location: Unknown Chemical Characterization: (Panich, Michelini, and Shackley 2013) Archaeological Occurrences: Santa Catarina, Vallecitos, Piedras Gordas, Murillo Comments: The location of the geologic source has not been determined. |
| Source: San Felipe Location: On the east coast near San Felipe Chemical Characterization: (Bouey 1984:57; Panich et al. 2012; Panich, Michelini, and Shackley 2013) Archaeological Occurrences: Southwestern Alta California, Bahía de los Angeles, San Quintín-El Rosario Other References: Banks 1971; Panich, Michelini, Bendímez, and Shackley 2013 Comments: The location of the geologic source has not been determined. |
| Source: Arroyo Matomí Location: On the Gulf coast south of San Felipe Chemical Characterization: Shackley 2004a Archaeological Occurrences: Guerrero Negro Other References: Bouey 1984:55-56; Douglas 1981 |
| Source: Puerto el Parral Location: In the northern Sierra Santa Isabel, south of Arroyo Matomí Chemical Characterization: Moore 2001; Panich, Michelini, and Shackley 2013; Shackley 1998a, 1998b Archaeological Occurrences: San Quintín Comments: This is an eroded surface deposit with small nodules averaging 5-7 cm in length. This may be the same source as Arroyo Matomí. |
| Source: Kiekierly Location: On the Gulf coast, about 5 km south of Puertecitos Chemical Characterization: Panich, Michelini, and Shackley 2013 Archaeological Occurrences: Laguna Chapala Comments: The location of the geologic source has not been determined. |
| Source: El Regino Location: On the Gulf coast about 10 km south of Puertecitos Chemical Characterization: Panich, Michelini, and Shackley 2013 Archaeological Occurrences: In the vicinity of the source |
| Source: San Luis Gonzaga Location: On the east coast near San Luis Gonzaga Chemical Characterization: Shackley 1997 Archaeological Occurrences: Bahía de los Angeles Comments: Initially designated as Unknown D |
| Source: Isla Angel de la Guarda Location: On an island in the central Gulf of California; however, Thomas Bowen questions whether the true source of this chemical type is on Isla Angel de la Guarda Chemical Characterization: Shackley 1994 Archaeological Occurrences: Bahía de los Angeles, San Borja, Guerrero Negro |
| Source: Unknown A Location: not identified Chemical Characterization: (Shackley 1995) Archaeological Occurrences: San Borja, Bahía de los Angeles, Bahía Concepción Comments: Nodule and large core at Bahía de los Angeles suggests that the source may be near there |
| Source: Unknown C Location: not identified Chemical Characterization: (Shackley 1994) Archaeological Occurrences: Bahía de los Angeles |
| Source: Unknown D Location: not identified Chemical Characterization: (Shackley 1994) Archaeological Occurrences: Bahía de los Angeles |
| Source: Unknown E Location: not identified Chemical Characterization: (Shackley 1995) Archaeological Occurrences: Bahía de los Angeles |
| Source: Ensenada del Pescador Location: On the east coast southeast of Bahía de los Angeles Chemical Characterization: Shackley 1995 Archaeological Occurrences: Possible prehistoric use of obsidian at the source Comments: One nodule with a flake scar has been found |
| Source: Valle de Azufre Location: Near the east coast northeast of San Ignacio Chemical Characterization: Gutiérrez and Hyland 2002:316; Hyland 1997:262; Shackley et al. 1996:723; on line Archaeological Occurrences: Sierra de San Francisco, Vizcaíno Desert, Isla Cedros, Bahía Concepción, Bahía de los Angeles, San Javier Comments: This is the largest and most intensively exploited source known in Baja California. Other References: Hyland and Gutiérrez 1995b; Ritter and Payen 1992:263; Tuohy 1978:80 |
| Source: Punta Mangles Location: On the east coast north of Loreto Chemical Characterization: Bouey 1984:57 Archaeological Occurrences: Bahía Concepción Other References: Ritter 1979a:120; Shackley et al. 1996:727 |
(References in parentheses for chemical characterizations are based on archaeological specimens rather than source samples.)
Chemically Sourced Archaeological Specimens
| VICINITY | SITE | SOURCED SPECIMENS | REFERENCES |
| San Quintín | PASE 102 | Puerto El Parral: 1 | Moore 2001 |
| San Quintín | PASE 138 | Puerto El Parral: 1 | Moore 2001 |
| San Quintín | PASE 151 | Puerto El Parral: 9 Arroyo Matomí: 1 | Moore 2001 |
| San Quintín | PASE 161 | Puerto El Parral: 1 | Moore 2001 |
| San Quintín | PASE 185 | Unknown B: 1 | Moore 2001 |
| San Quintín | PASE 186 | Puerto El Parral: 3 | Moore 2001 |
| San Quintín | PASE 206 | San Felipe: 1 | Moore 2001 |
| San Quintín | PASE 241 | Puerto El Parral: 1 | Moore 2001 |
| San Quintín | PASE 249 | Puerto El Parral: 3 | Moore 2001 |
| San Quintín | PASE 268 | San Felipe: 1 | Moore 2001 |
| San Quintín | PASE 282 | San Felipe: 1 | Moore 2001 |
| San Borja | Agua de Higuera | Unknown A: 8 | Shackley 2004b |
| San Borja | Valle San Julian | Isla Angel de la Guarda: 1 | Shackley 2004b |
| San Borja | Camino San Borja | Unknown A: 1 | Shackley 2004b |
| San Borja | San Ignacito | Valle de Azufre: 2 Isla Angel de la Guarda: 1 Unknown A: 1 | Shackley 2004b |
| San Borja | Montevideo | Isla Angel de la Guarda: 2 | Shackley 1997 |
| San Borja | UCBC-53 | Isla Angel de la Guarda: 4 Unknown A: 1 | Shackley 1995 |
| San Borja | UCBC-61 | Isla Angel de la Guarda: 5 | Shackley 2004a, 2009 |
| Bahía de los Angeles | Aguaje de San Juan | Isla Angel de la Guarda: 28 Unknown A: 19 San Felipe: 1 | Shackley 1994, 1995, 1997 |
| Bahía de los Angeles | Las Tinajas | Unknown A: 1 | Shackley 1995 |
| Bahía de los Angeles | Campo Caguama | Isla Angel de la Guarda: 2 | Shackley 1995 |
| Bahía de los Angeles | UCBC-7 | Isla Angel de la Guarda: 1 | Shackley 1994 |
| Bahía de los Angeles | UCBC-13 | Isla Angel de la Guarda: 4 | Shackley 1994, 1997 |
| Bahía de los Angeles | UCBC-16 | Unknown C: 1 | Shackley 1994 |
| Bahía de los Angeles | UCBC-18 | Isla Angel de la Guarda: 3 | Shackley 1994 |
| Bahía de los Angeles | UCBC-19 | Isla Angel de la Guarda: 5 Unknown D: 1 | Shackley 1994 |
| Bahía de los Angeles | UCBC-30 | Isla Angel de la Guarda: 4 Unknown A: 1 | Shackley 1995, 1997 |
| Bahía de los Angeles | UCBC-45 | Isla Angel de la Guarda: 3 | Shackley 1995 |
| Bahía de los Angeles | UCBC-46 | Isla Angel de la Guarda: 3 Unknown A: 1 | Shackley 1995 |
| Bahía de los Angeles | UCBC-47 | Isla Angel de la Guarda: 3 Unknown E: 1 | Shackley 1995 |
| Guerrero Negro | LM-1 | Valle de Azufre: 2 | Shackley 1999:311, 2002:209 |
| Guerrero Negro | LM-2 | Valle de Azufre: 6; unknown: 1 | Shackley 1999:311, 2002:209 |
| Guerrero Negro | LM-4 | Valle de Azufre: 3 | Shackley 2002:209 |
| Guerrero Negro | LM-5 | Valle de Azufre: 3; unknown: 1 | Shackley 2002:209 |
| Guerrero Negro | LM-6 | Valle de Azufre: 4; unknown: 1 | Shackley 2002:209 |
| Guerrero Negro | LM-7 | Valle de Azufre: 3 | Shackley 2002:209 |
| Guerrero Negro | LM-8 | Valle de Azufre: 1; unknown: 1 | Shackley 2004a, 2009 |
| Guerrero Negro | LM-9 | Valle de Azufre: 1; Isla Angel de la Guarda: 1 | Shackley 2004a, 2009 |
| Guerrero Negro | LM-10 | Valle de Azufre: 3 | Shackley 2004a, 2009 |
| Guerrero Negro | LM-11 | Valle de Azufre: 2 | Shackley 2004a, 2009 |
| Guerrero Negro | LM-12 | Valle de Azufre: 2 | Shackley 2004a, 2009 |
| Guerrero Negro | LM-13 | Valle de Azufre: 1 | Shackley 2004a, 2009 |
| Guerrero Negro | LM-15 | Valle de Azufre: 1 | Shackley 2004a, 2009 |
| Guerrero Negro | LM-18 | Valle de Azufre: 3; Puerto El Parral: 1 | Shackley 2004a, 2009 |
| Guerrero Negro | LGN-1 | Valle de Azufre: 3 | Shackley 1999:311, 2002:209 |
| Guerrero Negro | LGN-3 | Valle de Azufre: 1; unknown: 1 | Shackley 2002:209 |
| Guerrero Negro | LGN-4 | Valle de Azufre: 1 | Shackley 1999:311 |
| Guerrero Negro | LGN-14 | Valle de Azufre: 1 | Shackley 1999:311 |
| Guerrero Negro | LGN-18 | Valle de Azufre: 2 | Shackley 2002:209 |
| Guerrero Negro | LGN-19 | Valle de Azufre: 1 | Shackley 1999:311 |
| Guerrero Negro | LGN-20 | Valle de Azufre: 1 | Shackley 1999:311 |
| Guerrero Negro | LGN-22 | Valle de Azufre: 1 | Shackley 1999:311 |
| Guerrero Negro | LGN-26 | Valle de Azufre: 1 | Shackley 1999:311 |
| Guerrero Negro | LGN-28 | Valle de Azufre: 1 | Shackley 1999:311 |
| Guerrero Negro | LGN-31 | Valle de Azufre: 1 | Shackley 2002:209 |
| Guerrero Negro | Laguna Ojo de Liebre | Valle de Azufre: 5 | Ritter and Payen 1992:263 |
| Guerrero Negro | -- | Valle de Azufre: 4 | Shackley 1999:311 |
| San Ignacio | Valle de Azufre quarry | Valle de Azufre: 1 | Hyland 1997:450-451 |
| San Ignacio | Vizcaíno sites | Valle de Azufre: 33 Unknown A: 1 | Hyland 1997:450-451 |
| San Ignacio | Cueva Pintada | Valle de Azufre: 11 | Hyland 1997:451 |
| San Ignacio | Cuesta Blanca | Valle de Azufre: 2 | Hyland 1997:451 |
| San Ignacio | Cueva Soledad | Valle de Azufre: 4 | Hyland 1997:451 |
| San Ignacio | Los Corralitos | Valle de Azufre: 80 Unknown A: 1 | Hyland 1997:451-454 |
| San Ignacio | Costa sites | Valle de Azufre: 85 | Hyland 1997:454-456 |
| San Ignacio | Bahía Asunción | Valle de Azufre: 10 | Hyland 1997:456-457 |
| San Ignacio | Rancho El Batequi | Valle de Azufre: 1 | Gutiérrez and Hyland 1994a; Hyland and Gutiérrez 1995 |
| San Ignacio | miscellaneous | Valle de Azufre: 24 | Hyland 1997:457 |
| Bahía Concepción | -- | Valle de Azufre: 20 Punta Mangles: 2 Unknown A: 1 | Shackley et al. 1996:727 |
| San Javier | -- | Valle de Azufre: 1 | Carmean 1994b:72 |
Hydration Readings on Archaeological Specimens
| VICINITY | SITE | SOURCE | HYDRATION (microns) | REFERENCES |
| El Rosario | Las Pintas | -- | 4.7 | Meighan 1978:10 |
| San Fernando | Velicatá | -- | 3.0 | Meighan 1978:10 |
| San Borja | Agua de Higuera | Unknown A | 3.8, 4.0, 4.0, 4.0, 5.5, 6.0, 6.1, 7.9 | -- |
| San Borja | Agua de Higuera | -- | 3.9, 4.0, (4.0 + 5.6), (4.1 + 5.1 + 8.7), (4.1 + 6.0), 4.2, 4.2, (4.3 + 5.6), 4.6, 4.7, 4.9, (4.9 + 7.2), 5.0, 5.0, 5.3, 6.2, 7.3 | -- |
| San Borja | Valle San Julian | Isla Angel de la Guarda | 3.5 | -- |
| San Borja | Valle San Julian | -- | 3.0, 3.5 | -- |
| San Borja | Montevideo | Isla Angel de la Guarda | 1.1 | Ritter 1997 |
| San Borja | UCBC-53 | Isla Angel de la Guarda | 4.2, 5.9, 8.9 | Ritter 1995b, etc. |
| San Borja | UCBC-53 | Unknown A | 4.6, 6.2 | Ritter 1995b, etc. |
| San Borja | UCBC-53 | Valle Azufre | 3.5, 4.0 | -- |
| San Borja | UCBC-53 | -- | 3.0, (4.1 + 5.0), 6.6 | -- |
| San Borja | UCBC-61 | Isla Angel de la Guarda | 3.8, 3.9 | Carpenter 2009 |
| San Borja | Camino San Borja | Unknown A | 5.0 | -- |
| Bahía de los Angeles | Aguaje de San Juan | Isla Angel de la Guarda | 5.3 | Ritter 1994b |
| Bahía de los Angeles | Aguaje de San Juan | Unknown A | 2.4, 3.8, 5.4, 5.8, 6.0, 7.2, 8.8 | Ritter 1995b, 1997 |
| Bahía de los Angeles | Las Tinajas | Unknown A | 7.7 | Ritter 1995b |
| Bahía de los Angeles | Ensenada El Pescador | Ensenada El Pescador | 13.3 | Ritter 1995b |
| Bahía de los Angeles | UCBC-7 | Isla Angel de la Guarda | 1.6 | Ritter 1994b |
| Bahía de los Angeles | UCBC-13 | Isla Angel de la Guarda | 2.3, 4.6 | Ritter 1994b, 1997 |
| Bahía de los Angeles | UCBC-16 | Unknown C | 1.5 | Ritter 1994b |
| Bahía de los Angeles | UCBC-18 | Isla Angel de la Guarda | 2.7, 2.8 | Ritter 1994b |
| Bahía de los Angeles | UCBC-19 | Isla Angel de la Guarda | 2.7, 3.5, 3.6, 5.7 | Ritter 1994b |
| Bahía de los Angeles | UCBC-19 | Unknown D | 2.0 | Ritter 1994b |
| Bahía de los Angeles | UCBC-30 | Isla Angel de la Guarda | 1.5, 3.9, 4.1, 4.2 | Ritter 1995b, 1997 |
| Bahía de los Angeles | UCBC-45 | Isla Angel de la Guarda | 4.0, 5.0 | Ritter 1995b |
| Bahía de los Angeles | UCBC-46 | Isla Angel de la Guarda | 4.2, 5.6 | Ritter 1995b |
| Bahía de los Angeles | UCBC-46 | Unknown A | (2.6 + 3.3) | Ritter 1995b |
| Bahía de los Angeles | UCBC-47 | Isla Angel de la Guarda | 3.7, 4.4, 5.5 | Ritter 1995b |
| Isla Angel de la Guarda | Arroyo los Mochos | Isla Angel de la Guarda | 6.0 | Ritter 1994b |
| Guerrero Negro | LM-1 | Valle de Azufre | 3.0 | King 1999:314 |
| Guerrero Negro | LM-1 | Valle de Azufre? | 2.6, 3.1 | King 1999:314 |
| Guerrero Negro | LM-2 | Valle de Azufre | 2.4, 3.4, 4.1, 5.3, 6.0 | Carpenter 2002:214; King 1999:315 |
| Guerrero Negro | LM-2 | Valle de Azufre? | (1.4 + 2.8), 2.5, 3.1 | King 1999:314-315 |
| Guerrero Negro | LM-2 | unknown | 3.1 | Carpenter 2002:214 |
| Guerrero Negro | LM-4 | Valle de Azufre | 2.1, (2.2 + 2.7), 2.9 | Carpenter 2002:214 |
| Guerrero Negro | LM-5 | Valle de Azufre | 2.7, 2.8, 4.1 | Carpenter 2002:214 |
| Guerrero Negro | LM-5 | unknown | 4.0 | Carpenter 2002:214 |
| Guerrero Negro | LM-6 | Valle de Azufre | 1.9, 2.7, 3.2, (5.4 + 6.0) | Carpenter 2002:214 |
| Guerrero Negro | LM-6 | unknown | 2.1 | Carpenter 2002:214 |
| Guerrero Negro | LM-7 | Valle de Azufre | 2.5 | Carpenter 2002:214 |
| Guerrero Negro | LM-8 | Valle de Azufre | 2.9 | Carpenter 2009 |
| Guerrero Negro | LM-8 | Unknown | 3.4 | Carpenter 2009 |
| Guerrero Negro | LM-9 | Valle de Azufre | 3.9 | Carpenter 2009 |
| Guerrero Negro | LM-9 | Isla Angel de la Guarda | 3.9 | Carpenter 2009 |
| Guerrero Negro | LM-10 | Valle de Azufre | 3.5, 3.9 | Carpenter 2009 |
| Guerrero Negro | LM-11 | Valle de Azufre | 3.2, 3.3 | Carpenter 2009 |
| Guerrero Negro | LM-12 | Valle de Azufre | (2.6 + 3.7 + 4.9), (3.5 + 5.4) | Carpenter 2009 |
| Guerrero Negro | LM-13 | Valle de Azufre | 2.8 | Carpenter 2009 |
| Guerrero Negro | LM-15 | Valle de Azufre | 4.0 | Carpenter 2009 |
| Guerrero Negro | LM-18 | Valle de Azufre | 3.1, 4.0 | Carpenter 2009 |
| Guerrero Negro | LM-18 | Arroyo Matomí | 4.0 | Carpenter 2009 |
| Guerrero Negro | LGN-1 | Valle de Azufre | 1.2, 1.8, 2.2, 2.5, 2.7, 2.8, 4.2 | Carpenter 2002:214; King 1999:315; Ritter 1999:213 |
| Guerrero Negro | LGN-1 | Valle de Azufre? | 0.0, 2.0, 2.5, 2.6, 2.7, 2.7, 3.6 | King 1999:314 |
| Guerrero Negro | LGN-2 | Valle de Azufre | 2.6 | Ritter 1999:213 |
| Guerrero Negro | LGN-3 | Valle de Azufre | 1.1, 2.6 | Carpenter 2002:214; Ritter 1999:213 |
| Guerrero Negro | LGN-3 | Valle de Azufre? | 2.3, 2.6 | King 1999:314 |
| Guerrero Negro | LGN-3 | unknown | 3.8 | Carpenter 2002:214 |
| Guerrero Negro | LGN-4 | Valle de Azufre | 2.7, 2.7 | King 1999:315; Ritter 1999:213 |
| Guerrero Negro | LGN-4 | Valle de Azufre? | 2.7, 2.7 | King 1999:213 |
| Guerrero Negro | LGN-9 | Valle de Azufre? | 2.1 | King 1999:314 |
| Guerrero Negro | LGN-10 | Valle de Azufre? | 2.7 | King 1999:314 |
| Guerrero Negro | LGN-13 | Valle de Azufre | 2.5 | Ritter 1999:213 |
| Guerrero Negro | LGN-14 | Valle de Azufre | 4.0 | King 1999:314 |
| Guerrero Negro | LGN-17 | Valle de Azufre? | 2.6 | King 1999:314 |
| Guerrero Negro | LGN-18 | Valle de Azufre | 1.8, 2.4 | Carpenter 2002:214 |
| Guerrero Negro | LGN-18 | Valle de Azufre? | (2.6 + 4.2) | King 1999:314 |
| Guerrero Negro | LGN-19 | Valle de Azufre | 2.8 | King 1999:315 |
| Guerrero Negro | LGN-20 | Valle de Azufre | 2.5 | King 1999:315 |
| Guerrero Negro | LGN-20 | Valle de Azufre? | 1.6, 2.1 | King 1999:314-315 |
| Guerrero Negro | LGN-22 | Valle de Azufre | 3.1 | King 1999:315 |
| Guerrero Negro | LGN-22 | Valle de Azufre? | 0.0, 2.2 | King 1999:314 |
| Guerrero Negro | LGN-24 | Valle de Azufre? | 2.6 | King 1999:314 |
| Guerrero Negro | LGN-26 | Valle de Azufre | 2.9 | King 1999:315 |
| Guerrero Negro | LGN-26 | Valle de Azufre? | 1.7, (1.7 + 2.7) | King 1999:314 |
| Guerrero Negro | LGN-29 | Valle de Azufre? | 1.9, 2.4 | King 1999:314 |
| Guerrero Negro | LGN-30 | Valle de Azufre? | 1.5 | King 1999:314 |
| Guerrero Negro | -- | Valle de Azufre | 2.6, 2.9, 3.4, (3.7 + 4.8) | King 1999:314-315 |
| Guerrero Negro | -- | Valle de Azufre? | 0.0, 1.4, 2.9 | King 1999:314-315 |
| San Ignacio | Costa sites | Valle de Azufre? | (2.0 + 3.0), 3.6 | Gutiérrez and Hyland 2002:324; Hyland 1997:272 |
| San Ignacio | Los Corralitos | Valle de Azufre? | 2.1, 2.2, 2.8, 4.0 | Gutiérrez and Hyland 2002:324; Hyland 1997:272 |
| San Ignacio | Cuesta Blanca 27 | Valle de Azufre? | 0.0, 3.2 | Gutiérrez and Hyland 2002:324; Hyland 1997:272 |
| San Ignacio | Misc. sites | Valle de Azufre? | 3.1, 4.1 | Gutiérrez and Hyland 2002:324; Hyland 1997:272 |
| San Ignacio | Valle de Azufre quarry | Valle de Azufre? | 3.8, 3.8, 3.9, (4.0 + 4.8), 4.2, 4.2, 4.3, 4.4, (4.9 + 6.7), 5.2, (5.4 + 6.4), 5.7, 6.0, 6.1, 6.3, 6.4, 6.5, 6.5, (6.7 + 8.2), 6.9, (7.0 + 7.5), 7.2, 7.5, 7.6, (7.6 + 8.9), 7.7, 8.7, 9.1, 12.3 | Gutiérrez and Hyland 2002:325; Hyland 1997:273 |
| San Ignacio | Los Pozos | Valle de Azufre? | 2.5, 2.6, 2.9, 3.9 | Meighan 1978:10 |
| San Ignacio | Tinaja de Refugio | Valle de Azufre? | 2.1, 2.4, 2.6, 3.0, 3.1, 3.3, 3.4, 4.0 | Meighan 1978:10 |
| La Purísima | Rincon Grande | -- | 2.8 | Meighan 1978:10 |
| Bahía Concepción | BS-D11 | Valle de Azufre? | 0.0 | Ritter 1979a:121 |
| Bahía Concepción | BS-D15 | Valle de Azufre? | 1.4 | Ritter 1979a:121 |
| Bahía Concepción | BS-D37 | Valle de Azufre? | 5.3 | Ritter 1979a:121 |
| Bahía Concepción | BS-D49 | Valle de Azufre? | 1.5 | Ritter 1979a:121 |
| Bahía Concepción | BS-D50 | Valle de Azufre? | 2.2, 2.3, 3.8 | Ritter 1979a:121 |
| Bahía Concepción | BS-D54 | Valle de Azufre? | 2.6,3.8, 4.3, 5.8 | Ritter 1979a:121 |
| Bahía Concepción | BS-D58 | Valle de Azufre? | 2.9, 4.1 | Ritter 1979a:121 |
| Bahía Concepción | BS-D59 | Valle de Azufre? | 1.6, 1.7, 1.8, 2.3, 2.4, 3.0, 6.1 | Ritter 1979a:121 |
| Bahía Concepción | BS-D60 | Valle de Azufre? | 0.0, 0.1, 1.1, 1.6, 2.7, 2.8, 2.9, 3.1, 7.7 | Ritter 1979a:121 |
| Bahía Concepción | BS-D61 | Valle de Azufre? | 1.6, 3.0, 3.2 | Ritter 1979a:121 |
| Bahía Concepción | BS-D68 | Valle de Azufre? | 3.4 | Ritter 1979a:121 |
| Bahía Concepción | BS-D81 | Valle de Azufre? | 1.5, 2.9, 3.8 | Ritter 1979a:121 |
| Bahía Concepción | BS-D89 | Valle de Azufre? | 1.3, 2.9, 4.0 | Ritter 1979a:121 |
| Bahía Concepción | BS-D95 | Valle de Azufre? | 1.1, 1.5, 1.9, 2.8, 3.0, 3.8 | Ritter 1979a:121 |
| Bahía Concepción | BS-D100 | Valle de Azufre? | 1.4, 1.9, 10.1 | Ritter 1979a:121 |
| Bahía Concepción | BS-D106 | Valle de Azufre? | 2.6 | Ritter 1979a:121 |
| Bahía Concepción | BS-D125 | Valle de Azufre? | 1.1, 2.6, 3.9, (7.7) | Ritter 1979a:121 |
| Bahía Concepción | BS-D126 | Valle de Azufre? | 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.7, 1.8, 1.9, 2.0, 2.6, 2.7, 2.8, 2.9, 3.0, 3.5, 3.6, 3.8, (6.9), 10.1 | Ritter 1979a:121 |
| Bahía Concepción | BS-D128 | Valle de Azufre? | 0.4 | Ritter 1979a:121 |
| Bahía Concepción | BS-D134 | Valle de Azufre? | 1.0, 2.6 | Ritter 1979a:121 |
| Bahía Concepción | BS-D140 | Valle de Azufre? | 0.8, 1.6 | Ritter 1979a:121 |
| Bahía Concepción | BS-D152 | Valle de Azufre? | 2.2, 2.4, 2.7, 5.8 | Ritter 1979a:121 |
| Bahía Concepción | Transect I | Valle de Azufre? | 3.8 | Ritter 1979a:121 |
(Notes: "?" after a source indicates an unconfirmed but probable source, based on the site's location or other sourced specimens from the vicinity. Hydration readings in parentheses indicate multiple-band specimens. The Ritter 1979a data are based on his Table 13; there are some discrepancies with his text.)
Hydration Readings on Typed Projectile Points
| TYPE | VICINITY | HYDRATION (microns) | REFERENCES |
| Comondú Triangular | Bahía Concepción | 7 readings from 0.0 to 1.8; 2.8 (apparently reworked) | Ritter 1979a:180 |
| Comondú Serrated | San Ignacio | 2.9, 3.9, 4.0 | Meighan 1978:10, 16-17 |
| Comondú Serrated | San Ignacio | (2.0 + 3.0), 3.6 | Gutiérrez and Hyland 2002:324; Hyland 1997:272 |
| Comondú Serrated | Bahía Concepción | 3 readings from 0.8 to 2.1 | Ritter 1979a:180 |
| Comondú Series | Guerrero Negro | 0.0, 2.3, 2.6 | King 1999:314-315 |
| Guerrero Negro Series | Guerrero Negro | 1.1, 1.9, 2.0, 2.1, 2.1, 2.5, 2.5, 2.6, 2.6, 2.6, 2.7, 2.7, 3.0, 3.1, 4.0 | Carpenter 2002:214; King 1999:314-315; Ritter 1999:213 |
| Humboldt Concave Base | San Ignacio | 2.5 | Meighan 1978:10, 17 |
| Guajademí Split Stem | Guerrero Negro | 2.9 | King 1999:315 |
| Guajademí Split Stem | Bahía Concepción | 1.8 | Ritter 1979a:181 |
| Elko | Guerrero Negro | 3.4 | King 1999:314 |
| Elko | San Ignacio | 4.0 | Gutiérrez and Hyland 2002:324; Hyland 1997:272 |
| Elko Corner Notch-like | Bahía Concepción | 2.5 | Ritter 1979a:189 |
| La Paz-Gypsum Cave | San Ignacio | 2.6 | Meighan 1978:10, 17 |
| La Paz-Gypsum Cave | Bahía Concepción | 1.1, 2.6, 2.8, 3.5 | Ritter 1979a:194 |
| Zacatecas Broad Blade | Bahía Concepción | 1.9 (reworked) | Ritter 1979a:198-201 |
| Pinto Series | Bahía Concepción | 5.8 | Ritter 1979a:201 |
| Lanceolate | San Ignacio | 2.1, 2.2 | Gutiérrez and Hyland 2002:324; Hyland 1997:272 |
(Notes: Readings in parentheses indicate multiple-band specimens. Hydration measurements on older surfaces of reworked projectile points may give misleadingly old ages for newer point types. Damaged or resharpened surfaces on older point forms may give misleadingly young ages.)
Proposed Hydration Rates
("Y" = calendar years before the time of measurement; "H" = hydration reading, in microns)
| Rate: Y = 280 H Application: Baja California Basis: "Obsidian from the West Coast of Mexico has a widespread rate of 280 years per micron, and at least some Southern California obsidians also appear close to that rate." Editor's Comment: This formula may give ages that are substantially too late for early specimens. Reference: Meighan 1978:9 | |
| Rate: Y = 300 H or Y = 500 H Application: Bahía Concepción (probably primarily Valle de Azufre obsidian) Basis: "Principally on the basis of cross-dated artifact types with small hydration bands (i.e. small side-notched and triangular points)...a very rough approximation." Editor's Comment: This formula may give ages that are too late for early specimens. Reference: Ritter 1979a:120 | |
| Rate: Y = 322 H 1.5 Application: Bahía Concepción (probably primarily Valle de Azufre obsidian) Basis: "A compromise, purely empirical formula" based on the historic-period dropoff of obsidian use, early Holocene dating of the largest hydration measurements, and readings on chronologically diagnostic point types. Editor's Comment: In the original, the formula is incorrectly written as Y = 322 H2/3. Reference: Laylander 1987:435-436 |
(Hydration rates are likely to differ for obsidian coming from different geological sources, for specimens recovered from archaeological sites with different annual temperature regimes, and for specimens recovered from surface or subsurface contexts.)