20:
442:
The ultramafic xenoliths of the field are composed roughly of 80% spinel lherzolites, with lesser harzburgites, dunites, and pyroxenites. There is a high abundance of clinopyroxenes, about 35% by volume. Granulite xenoliths, interpreted as being derived from the lower crust, and peridotite xenoliths,
68:
Currently located in a shallow bay, the cones are found in two groups and two isolated islands. The
Northern group is composed of two cones, formed 126,000-90,000 years ago; the Southern group is larger, with two cones in the lagoon itself, and formed over a much larger and undetermined span of time.
297:
In Baja
California, high-volume volcanism ended around 15 Ma, shortly after the end of subduction. The third oldest volcano has reliably (using 40Ar/39Ar step-heating) been dated to 126,000 years ago. Following eruptions in the northern gulf area covered the San Quintin Volcanic Field in alkalic,
250:
The cessation of subduction forced the
Pacific and North American plates along the fault zones created alongside the San Benito and the Tosco-Abreojos faults, which run approximately parallel to the west coast of Baja. Over time, the direction of relative motion between these plates swung west,
288:
The ten volcanic complexes of San Quintín are all aligned N-S to NW-SE, parallel to an offshore fault, the
Santillán and Barrera line, and the main escarpment of the Gulf of California. The cones are therefore related to faulting, but no direct evidence for extensional faulting has been found.
171:
The ten volcanic complexes recognized in the San Quintín field include Media Luna and
Woodford in a northern group; a southern group consisting of Basu, Riveroll, Kenton, Picacho Vizcaino, Sudoeste, and Ceniza; and the isolated complexes Monte Mazo and Isla San Martín. A seacliff north of Basu
289:
Indirect evidence is found in the shared characteristics of the field with other
Quaternary volcanic fields linked to extensional faulting found throughout the province. This includes intraplate geochemical signatures in the magmas, and the presence of mantle and crustal xenoliths.
284:
The fault planes of Baja, going NNW-SSE, now accommodate plate boundary displacement and are currently active. In 1975, a collection of seismic events occurred after a dearth of events for a third of a century about 35 km (22 mi) northwest of the field.
185:
marking the west coast of the Baja
Peninsula and the eastern border of the depositional trough. On the other side lies the Stable Peninsula Province, an area mostly devoid of faulting (as opposed to the Gulf of California
878:
Luhr, James F., Paul
Kimberly, Lee Siebert, J. Jorge Aranda-Gomez, Todd B. Housh, Giuseppina Kysar Mattietti. 2006. México's Quaternary volcanic rocks: Insights from the MEXPET petrological and geochemical database. In:
180:
The
Santillán and Barrera Line, an important tectonic boundary, is found about 16 km (9.9 mi) NE of the volcanic field. At the boundary is an emerged portion of the Continental Borderland, a section of marine
461:. Alternatively, more complicated models suggest that a shallow, active shear zone deformed the xenoliths and it was only later that the deeper, source magmas modified the chemical composition of the field.
640:
Smith, J. T., Cenozoic marine mollusks and the paleogeography of the Gulf of
California, in The Gulf and Peninsular Province of the Californias, edited by J. P. Dauphin and B. A. Simoneit,
325:, mostly found a bit south of the San Quintín volcanic field, have high Mg, Ni, Cr, and Sr, low Rb, and high K/Rb and La/Yb ratios. The characteristics may suggest that one source is
69:
Most volcanic complexes in the field have a well-preserved scoria cone and lava apron, dotted with eruptive vents and lava flows. 42 eruptive units can be seen on the ground today.
692:
Lynch, D. J., T. E. Musselman, J. T. Gutmann, and P. J. Patchett, Isotopic evidence for the origin of Cenozoic volcanic rocks in the Pinacate volcanic field, northwestern México,
393:
peridotite. Due to this depth and the estimated speed of ascent, fractionation-elevated volatiles may have been important in driving the differentiated magmas to the surface.
198:
escarpment is found 7 km (4.3 mi) to the east, rising 40–80 m (130–260 ft) above the coastal plain, with more late Cretaceous sediments overlain by early
790:
Storey, M., Rogers, G., Saunders, A.D. and Terrell, D.J. 1989. San Quintín volcanic field, Baja California, Mexico: ‘within-plate’ magmatism following ridge subduction.
611:
Spencer, J. E. and W. R. Normark, Tosco-Abreojos fault zone: A Neogene transform plate boundary within the Pacific margin of southern Baja California, México,
764:
Saunders, A. D., et al., Geochemistry of Cenozoic volcanic rocks, Baja California, México: Implications for the petrogenesis of post-subduction magmas,
955:
940:
345:
mantle. This is the most obvious explanation of the observered intraplate characteristics of the alkali basalts, with lherzolite. Alternatively, the
537:
Luhr, J. F., Aranda-Gómez, J. J., and Housh, T. B. San Quintín Volcanic Field, Baja California Norte, México: Geology, petrology, and geochemistry.
361:, followed by postsubduction rifting. This explanation leaves the field untouched by a second subduction episode and leads more naturally to the
476:
Gorsline, D. S. and R. A. Stewart, Benthic marine exploration of Bahía de San Quintín, Baja California, 1960-61. Marine and Quaternary geology.
407:
can be inferred from samples taken from two cones, and small isotopic variations for the other cones indicate at least three mantle components.
247:. The southward-migrating triple junction passed San Quintín about 17 Ma and tip of Baja around 12 Ma, ending subduction in the Baja peninsula.
389:
of the primitive magmas. Xenolith abundance in the differentiated magma hint that fractional crystallization occurred within the mantle, below
950:
935:
631:, edited by V. A. Frizzel Jr., pp 219-236, Society of Economic Paleontologists and Mineralogists, Pacific Section, Bakersfield, Calif., 1984.
829:
Insight into the upper mantle beneath an active extensional zone: The spinel-peridotite xenoliths from San Quintín (Baja California, México)
386:
153:
The San Quintín Volcanic Field is found about 260 km (160 mi) south of the U.S. border and 200 km (120 mi) south of
337:
such that it melts. It has been proposed that the slab fully subducted in the relevant latitudes of the San Quintín field, so that a "
390:
243:
that migrated in opposite directions, northward and southward, along the coast. This stopped subduction and formed an interplate
891:
679:
Rebollar, C. J., A. Reyes, and M. Reichle, Estudio del enjambre de San Quintín, Baja California, México, ocurrido durante 1975,
539:
277:. By 3.5 Ma, the gulf region was the center of most of the Pacific-North American plate motion, generating new seafloor from
559:
Espindola-Cardeña, J. M., J. M. Romo-Jones, and M. Almeida-Vega, Gravimetria y estructura del Valle de San Quintín, B. C.
385:. Isotopic composition ranges overlap for primitive and differentiated rocks, indicating that the latter was derived from
744:
Rogers, G., et al., Geochemistry of Holocene volcanic rocks associated with ridge subduction in Baja California, México,
434:
and falling CaO, along with decreasing incompatible element abundances, are consistent with progressive partial melting.
99:
became more common, although extremely pure primitive magmas – virtually devoid of xenoliths and unusually rich in
945:
710:
Gastil, R. Gordon, Daniel Krummenacher, and John Minch. The record of Cenozoic volcanism around the Gulf of California,
666:
Angelier, J. B., et al., Fault tectonics of the Baja California Peninsula and the opening of the Sea of Cortez, México,
256:
495:
443:
interpreted as derived from the upper mantle, are particularly abundant in the Woodford, Media Luna, and Basu cones.
447:
410:
The primitive magmas differ from other reported intraplate-type mafic alkalic suites by having relatively high Al
154:
84:
62:
40:
930:
853:
270:
The northern protogulf was flooded as early as 13 Ma, and by 10 Ma, the region was experiencing eruptions of
858:
271:
96:
404:
598:
Mammerickx, J. and K. D. Klitgord, Northern East Pacific Rise: Evolution from 25 m.y.B.P. to the Present,
572:
Gastil, R. G., R. P. Phillips, and C. C. Allison, Reconnaissance geology of the State of Baja California,
202:
73:
145:
xenoliths on the peninsula. The largest and most abundant xenoliths are found in differentiated magmas.
585:
Atwater, T. A., Implications of plate tectonics for the Cenozoic evolution of western North America,
398:
373:
The basalt lavas of the San Quintín field have the same composition as ocean island basalts found in
334:
236:
182:
158:
811:
362:
338:
19:
260:
165:
106:– still dominated at the young cones. These primitive magmas originated from progressive
65:. The lava shields appear to have first grown as subaqueous volcanoes that emerged as islands.
458:
812:
Hot-spots, mantle plumes and a model for the origin of ultramafic xenoliths in alkali basalts
627:
Hausback, B. P., Cenozoic volcanic and tectonic evolution of Baja California Sur, México, in
795:
694:
544:
315:
206:
118:
59:
450:
394:
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244:
240:
157:, Baja California, at a latitude of ~30.5°N. Today, the cones rest on over a kilometer of
122:
107:
828:
490:
401:
in the source, led to a decrease in abundances of these volatiles as the field evolved.
799:
326:
229:
195:
263:. Simultaneously, normal faulting throughout the protogulf further weakened the areal
924:
342:
226:
36:
777:
Kay, R. W., Aleutian magnesian andesites: Melts from subducted Pacific Ocean crust,
382:
350:
330:
881:
264:
239:. The arrival of the Pacific-Farallon spreading center at the trench formed two
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52:
32:
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187:
138:
134:
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Neogene-Quaternary Continental Margin Volcanism: A Perspective from México
311:
299:
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161:
92:
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Curray, J. R., et al., Leg 64 seeks evidence of development of basins,
354:
333:, i.e. a subducting plate adds volatiles to the ultramafic rock of the
100:
548:
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basalts (MORB) at spreading centers following areal transform faults.
454:
453:, which may have recorded plastic deformation that occurred with the
378:
374:
274:
130:
111:
80:
44:
726:
Sawlan, M. G., Magmatic evolution of the Gulf of California rift,
302:-rich basalts. General characteristics of these basalts, known as
88:
77:
18:
885:, Geological Society of America Special Paper 402, pp. 1–44.
125:
xenoliths found are mostly spinel lherzolite, with the final 20%
252:
55:
and ending about 3000 years ago. It is one of several known
310:
found in Baja California Sur, as well as high-magnesium
349:
could be formed from partial melting in the mantle of
72:
The San Quintín field is the only known location of
760:
758:
756:
754:
137:. The San Quintín field is also the only source of
740:
738:
736:
706:
704:
629:Geology of the Baja California Peninsula Publ. 39
563:, pp 10-15, Union Geofis. Mex. Mexico City, 1991.
418:and Yb, as well as low ratios of La/Yb and CaO/Al
491:The San Quintín volcanic field, lower California
397:in the mantle, or the progressive exhaustion of
533:
531:
529:
527:
525:
623:
621:
523:
521:
519:
517:
515:
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164:-Quaternary sediment overlaid on the volcanic
722:
720:
23:Aerial view of the San Quintín Volcanic Field
8:
221:period until about 29 million years ago (29
168:of the lower Cretaceous Alistos Formation.
31:is a collection of ten or eleven volcanic
172:exposes what may be an eleventh complex.
16:Volcanic field in Baja California, Mexico
469:
341:" allowed the plate to directly access
235:eastward beneath the west coast of the
190:) and covered in pre-batholithic and
7:
827:Cabanes, N., and J.-C. C. Mercier,
117:at unusually shallow levels in the
800:10.1111/j.1365-3121.1989.tb00352.x
87:. The oldest cones mainly erupted
14:
381:, where they are associated with
149:Description of the volcanic field
956:Landforms of Baja California Sur
941:Volcanoes of Baja California Sur
766:J. Volcanol. Geotherm. Res., 32
540:Journal of Geophysical Research
833:Contrib. Mineral. Petrol., 100
779:J. Volcanol. Geotherm. Res., 4
1:
951:Landforms of Baja California
936:Volcanoes of Baja California
849:"San Quintín Volcanic Field"
816:Earth Planet. Sci.Lett., 28
496:American Journal of Science
457:rise of mantle through the
213:Evolution of areal faulting
194:crystalline rocks. Another
972:
387:fractional crystallization
306:, are also similar to the
29:San Quintín Volcanic Field
446:The site exhibits strong
176:Regional geologic setting
85:Baja California peninsula
41:Baja California peninsula
854:Global Volcanism Program
712:Geol. Soc, Am. Bull., 90
574:Mem. Geol. Soc. Am., 140
95:. As the field evolved,
859:Smithsonian Institution
587:Geol. Soc. Am. Bll., 81
543:100:10353–10380, 1995.
365:that are also present.
63:volcanic fields in Baja
91:with occasional small
47:. The field formed by
24:
405:Crustal contamination
399:incompatible elements
22:
698:, 29, 295-302, 1993.
600:J. Geophys. Res., 87
363:ocean island basalts
237:North American Plate
97:differentiated magma
946:Volcanism of Mexico
903: /
683:(4), 331-358, 1982.
668:J. Struct. Geol., 3
35:situated along the
589:, 3513-3536, 1970.
561:GEOS Bol. Inf., 11
261:Gulf of California
245:transform boundary
49:repeated eruptions
25:
549:10.1029/95JB00037
499:15:337-345, 1928.
489:Woodford, A. O.,
459:low-velocity zone
83:volcanism on the
51:beginning in the
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818:, 261-274, 1975.
808:
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769:
768:, 223-245, 1987.
762:
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748:, 389-392, 1985.
742:
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715:
714:, 839-857, 1979.
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681:Geofís, Int., 21
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670:, 347-357, 1981.
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480:, 282-319, 1962.
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251:accommodated by
241:triple junctions
207:marine sediments
89:primitive magmas
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931:Volcanic fields
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907:30.47°N 116.0°W
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873:Further reading
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842:External links
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308:alkali basalts
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230:Farallon Plate
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196:marine terrace
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159:unconsolidated
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862:. Retrieved
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369:Geochemistry
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335:upper mantle
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127:harzburgites
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33:cinder cones
28:
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746:Nature, 315
448:deformation
426:. Rising Al
265:lithosphere
192:batholithic
139:peridotitic
135:pyroxenites
104:phenocrysts
53:Pleistocene
925:Categories
864:2021-06-27
792:Terra Nova
613:Geology, 7
465:References
272:tholeiitic
219:Cretaceous
188:escarpment
183:deposition
143:granulitic
123:ultramafic
115:lherzolite
74:intraplate
57:Quaternary
438:Xenoliths
391:entrained
359:amphibole
329:-derived
316:Aleutians
312:andesites
293:Volcanism
257:protogulf
253:extension
233:subducted
217:From the
93:xenoliths
898:116°00′W
455:diapiric
451:textures
377:and the
347:bajaites
323:bajaites
304:bajaites
300:diopside
200:Tertiary
166:basement
155:Ensenada
895:30°28′N
355:apatite
353:mantle
314:of the
275:basalts
259:of the
255:in the
227:oceanic
225:), the
131:dunites
101:olivine
81:alkalic
39:of the
695:Lithos
379:Azores
375:Hawaii
321:These
133:, and
121:. The
119:mantle
112:spinel
76:-type
60:period
45:Mexico
331:melts
78:mafic
357:and
327:slab
162:Plio
141:and
27:The
796:doi
545:doi
110:of
43:in
927::
857:.
851:.
831:,
814:,
753:^
735:^
719:^
703:^
620:^
504:^
493:.
318:.
267:.
223:Ma
209:.
129:,
867:.
798::
547::
432:3
430:O
428:2
424:3
422:O
420:2
416:3
414:O
412:2
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