370:
299:
41:
258:, its total thickness reaches 5,000 feet. Diatomite is a major component of the formation in the hills north and south of Lompoc, where it is interbedded with diatomaceous clay shale. The lowest portion of the formation in the Purisima Hills contains tar, for it is here that the unit forms an impermeable cap on the underlying Monterey
314:; as a result, sediments deposited later in the period tend to be finer-grained, since the deeper the water, the finer the sediment deposited there. Even though the deposition environment was far from shore, the unit contains occasional conglomerates. One such unit near More Mesa Beach in Santa Barbara, containing
222:, with considerable regional variation, and was deposited in a moderately deep marine environment at a depth of approximately 500–5,000 feet (150–1,520 m). Since some of its diatomites, along with those of the underlying Monterey Formation, are of unusual purity and extent, they can be mined as
415:
While most of the oil found in the
Sisquoc Formation has gotten there by migrating upward from the underlying Monterey Formation, the primary source rock for petroleum in southwestern California, sometimes the Sisquoc is itself a source rock. In places the formation contains enough organic carbon –
349:
Numerous fossils have been found in the
Sisquoc Formation. Within Santa Barbara County, the Sisquoc alone has produced 127 separate finds, which are catalogued by the University of California, Berkeley Museum of Paleontology. In addition to the abundant diatoms which make up the diatomite,
273:
it weathers to hilly terrain with gray soil that supports grasses. It outcrops rarely, being best exposed in road cuts, along rivers, and especially along the cliffs on the coast, where it is easily visible from the beach. Many prominent exposures of the
Sisquoc occur at the beaches along the
463:
Minor, S.A., Kellogg, K.S., Stanley, R.G., Gurrola, L.D., Keller, E.A., and Brandt, T.R., 2009, Geologic Map of the Santa
Barbara Coastal Plain Area, Santa Barbara County, California: U.S. Geological Survey Scientific Investigations Map 3001, scale 1:25,000, 1 sheet, pamphlet, 38
614:
Nuel C. Henderson, Jr. and Pedro C. Ramirez. "Control exerted by lithologic variations and pebbly units on petroleum occurrences in the
Pliocene Upper Sisquoc Formation, Casmalia Hills, Santa Maria Basin, California." SEPM Core Workshop No. 14. San Francisco, June 3, 1990.
431:
The diatomites of the
Sisquoc, like those of the Monterey, can function both as oil-bearing units – where they have been capped with impermeable beds – or they may be oil-free, in which case, if they are near the surface and of sufficient purity, they can be mined as
250:, in northern Santa Barbara County, about a mile east of its confluence with Foxen Canyon. In this location the formation consists mainly of sandstones, but also some siltstone and diatomite, and is about 1,100 feet thick. In other places, such as in the
329:
of these tiny marine creatures form diatomite, and some of their organic remains persist as the high organic carbon content of parts of the formation (when conditions are right, these organic remains form
310:
environment, at a depth of between 150 and 1500 meters, between approximately 4 and 6 million years ago – the upper
Miocene and lower Pliocene eras. During this time, the region was continuing to
318:
from the underlying
Monterey Formation, was probably the result of a submarine landslide, bringing down pebbles and boulders from that older formation, which had already been uplifted onshore.
66:
680:
737:
401:
338:
302:
Close-up photograph of the
Sisquoc Formation, showing the friable, planiform nature of the rock on a weathered surface. Rock hammer for scale.
412:, pebbly and high-porosity units contain a considerable amount of oil, while clay-rich and diatomaceous mudstones contain almost none.
350:
fossils include vertebrates such as sea lions and walruses, bony and cartilaginous fishes, and birds. Additional fossils include
531:
392:
As a stratigraphic member of petroleum reservoirs, it can be both a reservoir and a sealing unit. Sometimes, as in the
677:
620:
517:
448:
estimates that the Lompoc mine alone with its large reserves could meet the needs of the entire world for centuries.
445:
334:). South of the Santa Ynez Mountains, the ocean was deeper and the formation consists of finer muds and clays.
290:
and the hills to the south and southwest – well-weathered outcrops of the formation are often bleached white.
719:
742:
747:
588:. Vol. I (1998), Vol. II (1992), Vol. III (1982). PDF file available on CD from consrv.ca.gov. p. 238
279:
554:
87:
Up to 1000 feet in Santa
Barbara area; 1100 feet at type locality; up to 5000 feet south of Lompoc.
490:
State of California, Department of Natural Resources, Division of Mines, Bulletin 150. 1950. 43.
409:
287:
243:
158:
584:
California Department of Conservation, Division of Oil, Gas, and Geothermal Resources (DOGGR).
219:
118:
718:. U.S. Geological Survey Minerals Yearbook, 2002. US Government Printing Office. Available
425:
270:
8:
386:
331:
283:
259:
183:
441:
433:
416:
up to six percent – to generate oil under the right conditions, such as burial in deep
397:
382:
374:
231:
223:
187:
77:
420:
with high enough temperature and sufficient time (several million years) to cause the
616:
513:
405:
477:. Bulletin 186, California Division of Mines and Geology. San Francisco, 1966. 51.
369:
396:, it serves as an impermeable cap rock to an oil-bearing unit, in that case in the
393:
322:
255:
179:
684:
265:
The Sisquoc Formation is not as resistant to erosion as other formations in the
326:
251:
62:
408:, it is an oil-bearing unit in its own right. In the Casmalia field, west of
731:
475:
Geology of the central Santa Ynez Mountains, Santa Barbara County, California
341:, in which diatomite is gradually replaced by sandstones of granitic origin.
337:
Going east along the Santa Ynez River, the Sisquoc Formation grades into the
275:
247:
230:
operates a mine in the Sisquoc and Monterey Formations in the hills south of
154:
45:
Sisquoc Formation at the stairs to More Mesa Beach, Santa Barbara, California
24:
266:
358:
351:
355:
311:
198:
age (from about 4 to 6 million years old). The formation consists of
676:
County of Santa Barbara. Paleontological Resources section from the
215:
207:
199:
108:
186:, both on the coast and in mountains near the coast. Overlying the
417:
203:
195:
100:
28:
440:, is in the Sisquoc and Monterey formations in the hills south of
421:
307:
191:
32:
437:
298:
286:. In the Santa Maria Basin – the area surrounding the city of
227:
315:
237:
211:
104:
40:
488:
Geology of Southwestern Santa Barbara County, California.
424:
from the decomposing organic matter to be matured, via
678:
Lompoc Wind Project Final Environmental Impact Report
586:
California Oil and Gas Fields, Volumes I, II and III
381:The Sisquoc Formation is important as a source of
436:. The world's largest such deposit, operated by
377:(2009), are a major source of diatomaceous earth.
325:was deposited as a fine mud, rich with diatoms.
269:sequence in coastal California, and south of the
729:
510:The Monterey Formation: From Rocks to Molecules.
306:The Sisquoc Formation was deposited in a middle
532:"Celite World Minerals sells for 217 million"
508:Isaacs, Caroline M. and Rullkötter, Jürgen.
642:
640:
638:
610:
608:
606:
596:
594:
738:Geology of Santa Barbara County, California
568:
566:
564:
555:"Post-Chumash History of the Gaviota Coast"
234:, the largest such operation in the world.
580:
578:
238:Type locality, description, and occurrence
39:
635:
603:
591:
293:
561:
529:
368:
297:
254:north of Lompoc, in and adjacent to the
575:
451:
246:for the Sisquoc Formation is along the
730:
672:
670:
364:
502:
321:The bulk of the Sisquoc north of the
667:
13:
552:
14:
759:
512:Columbia University Press, 2001.
400:; in other cases, such as in the
530:Abramson, Mark (July 23, 2005).
404:and the offshore portion of the
708:
699:
690:
658:
649:
626:
344:
546:
523:
493:
480:
467:
457:
157:, about 10 miles southeast of
1:
182:geologic unit widespread in
557:. Gaviota Coast Conservancy.
7:
10:
764:
361:, and remains of sponges.
262:of the Lompoc Oil Field.
164:
150:
145:
137:
129:
124:
114:
96:
91:
83:
73:
58:
50:
38:
23:
18:
373:Diatomite quarries near
655:Minor et al., Figure 13
159:Santa Maria, California
67:Santa Barbara Formation
378:
303:
294:Deposition environment
705:Isaacs et al., p. 213
600:Dibblee (1950), 43-44
372:
301:
664:Dibblee (1966) 53-54
452:References and notes
426:hydrocarbon cracking
332:petroleum reservoirs
271:Santa Ynez Mountains
743:Pliocene California
387:petroleum reservoir
365:Economic importance
184:Southern California
133:Southern California
25:Stratigraphic range
748:Miocene California
714:Dolley, Thomas P.
683:2010-07-05 at the
499:Dibblee, 1966. 51.
486:Dibblee, Thomas.
473:Dibblee, Thomas.
442:Lompoc, California
434:diatomaceous earth
428:, into petroleum.
402:Casmalia Oil Field
398:Monterey Formation
383:diatomaceous earth
379:
375:Lompoc, California
339:Tequepis Sandstone
304:
232:Lompoc, California
224:diatomaceous earth
188:Monterey Formation
78:Monterey Formation
696:DOGGR, p. 658-659
646:Dibblee (1966) 52
572:Dibblee (1966) 51
406:Ellwood Oil Field
190:, it is of upper
176:Sisquoc Formation
172:
171:
19:Sisquoc Formation
755:
723:
712:
706:
703:
697:
694:
688:
674:
665:
662:
656:
653:
647:
644:
633:
630:
624:
612:
601:
598:
589:
582:
573:
570:
559:
558:
550:
544:
543:
541:
539:
527:
521:
506:
500:
497:
491:
484:
478:
471:
465:
461:
394:Lompoc Oil Field
323:Santa Ynez River
256:Lompoc Oil Field
226:. France-based
43:
16:
15:
763:
762:
758:
757:
756:
754:
753:
752:
728:
727:
726:
713:
709:
704:
700:
695:
691:
685:Wayback Machine
675:
668:
663:
659:
654:
650:
645:
636:
631:
627:
613:
604:
599:
592:
583:
576:
571:
562:
551:
547:
537:
535:
534:. Lompoc Record
528:
524:
507:
503:
498:
494:
485:
481:
472:
468:
462:
458:
454:
367:
347:
296:
240:
46:
12:
11:
5:
761:
751:
750:
745:
740:
725:
724:
707:
698:
689:
666:
657:
648:
634:
625:
602:
590:
574:
560:
545:
522:
501:
492:
479:
466:
455:
453:
450:
366:
363:
346:
343:
295:
292:
252:Purisima Hills
239:
236:
170:
169:
166:
162:
161:
152:
148:
147:
143:
142:
139:
135:
134:
131:
127:
126:
122:
121:
116:
112:
111:
98:
94:
93:
89:
88:
85:
81:
80:
75:
71:
70:
63:Pico Formation
60:
56:
55:
52:
48:
47:
44:
36:
35:
21:
20:
9:
6:
4:
3:
2:
760:
749:
746:
744:
741:
739:
736:
735:
733:
721:
717:
711:
702:
693:
686:
682:
679:
673:
671:
661:
652:
643:
641:
639:
629:
622:
621:0-918985-84-6
618:
611:
609:
607:
597:
595:
587:
581:
579:
569:
567:
565:
556:
553:Palmer, Lex.
549:
533:
526:
519:
518:0-231-10585-1
515:
511:
505:
496:
489:
483:
476:
470:
460:
456:
449:
447:
443:
439:
435:
429:
427:
423:
419:
413:
411:
407:
403:
399:
395:
390:
388:
384:
376:
371:
362:
360:
357:
353:
342:
340:
335:
333:
328:
324:
319:
317:
313:
309:
300:
291:
289:
285:
281:
280:Santa Barbara
277:
276:Gaviota Coast
272:
268:
267:stratigraphic
263:
261:
257:
253:
249:
248:Sisquoc River
245:
244:type locality
235:
233:
229:
225:
221:
220:conglomerates
217:
213:
209:
205:
201:
197:
193:
189:
185:
181:
177:
168:Porter (1932)
167:
163:
160:
156:
155:Sisquoc River
153:
149:
144:
141:United States
140:
136:
132:
128:
123:
120:
117:
113:
110:
106:
102:
99:
95:
90:
86:
82:
79:
76:
72:
68:
64:
61:
57:
53:
49:
42:
37:
34:
30:
26:
22:
17:
715:
710:
701:
692:
660:
651:
628:
585:
548:
536:. Retrieved
525:
509:
504:
495:
487:
482:
474:
469:
459:
430:
414:
391:
380:
359:foraminifers
352:radiolarians
348:
345:Paleontology
336:
320:
305:
264:
241:
175:
173:
146:Type section
119:conglomerate
632:Isaacs, 220
538:October 23,
410:Santa Maria
288:Santa Maria
180:sedimentary
54:Sedimentary
732:Categories
623:p. 339-340
356:arenaceous
194:and lower
716:Diatomite
687:. 3.12-3
418:synclines
385:and as a
260:reservoir
216:diatomite
208:siltstone
200:claystone
151:Named for
109:diatomite
92:Lithology
84:Thickness
59:Underlies
681:Archived
282:west to
204:mudstone
196:Pliocene
165:Named by
125:Location
101:mudstone
74:Overlies
69:, others
31:, upper
29:Pliocene
27:: Lower
520:p. 211.
422:kerogen
312:subside
308:bathyal
284:Gaviota
192:Miocene
138:Country
97:Primary
33:Miocene
619:
516:
444:; the
438:Imerys
316:clasts
228:Imerys
218:, and
130:Region
327:Tests
278:from
212:shale
178:is a
115:Other
105:shale
720:here
617:ISBN
540:2010
514:ISBN
446:USGS
242:The
174:The
51:Type
734::
669:^
637:^
605:^
593:^
577:^
563:^
464:p.
389:.
354:,
214:,
210:,
206:,
202:,
107:,
103:,
65:,
722:.
542:.
Text is available under the Creative Commons Attribution-ShareAlike License. Additional terms may apply.
