Facies Relations in the Eocene-Oligocene in the Santa Ynez Mountains, California

Facies relations in the Eocene-Oligocene in the Santa Ynez Mountains, California

P. C. VAN DE KAMP, J. D. HARPER, J. J. CONNIFF & D. A. MORRIS

CONTENTS I General stratigraphy ...... 547 2 Description and interpretation of lithofacies ..... 549 (A) The Turbidite and marine lutite facies ..... 549 (B) The Proximal turbidite facies ...... 55 I (c) The Shallow marine facies ...... 554 (v) The Coastal facies ...... 557 3 Depositional history ...... 558 4 General paleogeography ...... 56o 5 Sedimentological processes ...... 56o 6 References ...... 564

SUMMARY Facies relationships between deep and shallow major regressive sequences. In the first, the marine to continental deposits in the Eocene- Juncal-Matilija sequence, thin-bedded tur- Oligocene sequence of the Santa Ynez Moun- bidites and marine lutites are overlain by, and tains, California, have been studied in detail are laterally equivalent to, very thick proximal to (I) determine interrelationships between turbidites which pass upward into shallow shallower and deeper marine sands (coastal marine and coastal sands. The major sand and turbidite); (2) establish criteria for the accumulations are in the basin margin shallow recognition of genetic sand types; (3) de- marine, coastal, and proximal turbidite facies. termine factors influencing facies distribution; The second regression, the Cozy Dell-Sespe and (4) propose hypotheses of marine sand sequence, lacks significant proximal turbidite deposition. The rocks studied include the deposits but has extensive shallow marine and Anita, Sierra Blanca, Juncal (with the Camino coastal deposits. Facies distribution and Cielo Member), Matilija, Cozy Dell, and stratigraphical sequence are explained as "Coldwater" formations but not the topmost respomes to the interplay of depositional and unit of the Eocene-Oligocene sequence, the structural processes. non-marine Sespe formation. Detailed stratigraphical mapping has clari- In landward sequence, the facies recognized fied correlation in the Eocene sequence to the include: Turbidites and marine lutites, Santa Ynez Mountains. Micropaleontology is proximal turbidites, shallow marine, coastal used in support of correlations and bathy- and continental facies. These occur in two metric interpretations.

EOCENE and Oligocene marine sandstones in the Santa Ynez Mountains and adjacent areas, on the north flank of the Ventura Basin (Fig. I), have been studied in detail to (I) determine interrelationships between shallower and deeper marine sands (coastal and turbidite), (2) establish criteria for the recognition of genetic sand types, (3) determine factors influencing facies distribution, and (4) propose hypotheses of marine sand deposition.

Jl geol. Soc. Land. vol. x3o, I974, pp. 545-565, I I figs. Printed in Northern Ireland.

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This sequence is suitable for the objectives of this study as there is continuous exposure of variable quality over a distance of I oo km from Ojai in the east, west to Point Conception (Fig. z). The sequence records deposition in a wide variety of environments ranging from deep water to continental. This range permits comparison of lithostratigraphical correlation and facies interpretation with biostratigraphical data and paleoecological interpretations, thereby contributing insight into microfaunal facies variation. The type section for the Ynezian and Bulitian Stages (Kleinpell & Weaver 1963) at Santa Anita Canyon, occurs in this sequence. Detailed study was confined to the area south of the Santa Ynez Fault, in the Santa Ynez Mountains (Fig. I) and north of this fault only reconnaissance was undertaken. Correlation across the fault was based on lithological similarity, micropalaeontological data and facies interpretation. In this study over I ooo microfaunal samples were examined by Conniff and Morris to give age and environmental data but only the most significant palaeontological results are summarized. Dibblee (I95o , I966 ) described the geology of the western and central Santa Ynez Mountains. Theses dealing with the distribution and origin of various units in the Eocene-Oligocene sequence include those by Jestes (I963), Stauffer (I965), and Johnson (i968). Other pertinent stratigraphical studies are by Kelley (~943),

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P~ntnceptlon ~ ~ Fillmore"

10 20 30 WVentura . , 10 Km=o 30 ~ AREA STUDIED BY RECONNAISSANCE Ve.....

\ F I G. I. Index map of the western Transverse Ranges area showing the general distribution of Eocene and Oligocene rocks in the shaded areas. The Santa Ynez Mountains lie south of the Santa Ynez Fault. Measured sections referred to in this study are indicated as numbered lines on the map as follows: z. West Cojo Canyon, 2. East Cojo Canyon, 3. Gato Canyon, 4. San Augustin Canyon, 5. Santa Anita Canyon, 6. Cuarta Canyon, 7. Gaviota Pass, 8. East Gaviota, 8A. Dos Vistas Ranch, 9. Santa Ynez Peak, i o. Tecolote Tunnel, ~ ~. Gibraltar Road, z2. Romero Road, 13. Divide Peak, ~4- Wheeler Springs. Major paleocurrent trends in the Eocene and Oligocene are shown by arrows. Most transport was from the north and east. Our data is supplemented by that of Jestes (1963).

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Page et al. (I95I), Bailey (z952), Kerr & Schenck (I928), Link (z972) and O'Brien (1972). In the broadest sense, the structure of the Santa Ynez Mountains west of Ojai is homoclinal, dipping steeply toward the south and locally overturned (e.g., Matilija Overturn, Kerr & Schenck I928). This homocline is truncated on the north by the Santa Ynez Fault (Fig. t). In detail, the structure is more complex. Several significant open folds trend obliquely (NW-SE) to the E-W trend of the mountains. The most significant fault in the area, the Santa Ynez Fault, shows northward thrusting as well as left-lateral displacement (Dibblee 1966). Other less significant faults occur within the homocline and appear to be associated with folding. Vertical and lateral offsets on these faults are generally on the order of several tens or hundreds of metres. I. General stratigraphy All the stratigraphical terminology given is lithostratigraphical and this, and applications, differ from previous work (Kelley z943, Dibblee I95% i966, Bandy & Kolpack 1963). The changes are based on litkostratigraphical and palaeontological correlations from east to west in the Santa Ynez Mountaim (Table I).

TAB LE 1 EOCENE-OLIGOCENE STRATIGRAPHY. NORTH FLANK OF VENTURA BASIN Comparison of correlations of earlier studies with this work.

Kleinpell and Weaver (1963) Page, Marks, (Dib~ee, 1950) Walker (19,51) van de Kamp and Harper (this work) Western Santa Eastern Santa Weste rn Eastern East Northeast Series Stage Stage Series Ynez Mtns. Ynez Mtns. Santa '~nez Santa Ynez Ventura Basin Ventura Basin

Oligoce,w Zemorrian Alegfia Upl~' (.) ""~L._ Sespe ? ? Refugian Oligoceno "Coldwater" "Coldwater" Upper (shale) Middle :zhlde) °'C~ter °' : ...... Co~dwater" Middle (ss) Lower (as)

Refugian Upper t shale) Upper (shale) I Upper (shale) I Upper (shale) F. Upper r.9 Cozy Dell Sand Cozy D(II Sand ~>. Cozy Dell Sand ~,. Cozy Dell Sand Lower (shale) Cozy Dell N ~> (Circle B Sz) '" O o o r..)o r_l r..) ¢.1 Lower (;hale) Lower (shale) i Lower (shale) ' Lower (shale) i Sacate Narizian Derrydale and (Dibblee, 1950; Matilija Matilij j Matilija Matilija Thorn Meadows Kelley, 1943) Narizian Eocene "Cozy Dell" Upper Upper Upper Juncal D Middle u,l

-~ CaminoCielo ~ ClminciCielo "~ Camino Cielo "Matilija" Sand ~ Saw Sand Ulatisian Ulatbian

: Lower i Lov~er LoMr Junr~ ? Mu~oFm Sierra Bh,nca ? Penutian ,~ SierraBlancl Sierra Blanca Sierra Blanca Penutian Lower :"Poppin' S 1ale") Bulitian Bulitian Paleocene " n " ' Paleoc~ne Ynezian Ynezian ///f/I// //--7-7-7' ? :"77"~ I Maestrichtian Up0~r Cretaceous Espada lu$ to Cretaceous I Cretace( Cretaceous Cretaceous Honda I Campanian

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South of the Santa Ynez Fault, the Eocene-Oligocene clastic sequence (Fig. 2) is underlain disconformably by Upper Cretaceous siltstones and sandstones (Jalama formation). North of the fault, the Eocene is unconformable on either Mesozoic granitic, Franciscan metamorphic, or Lower to Upper Cretaceous sedimentary rocks. Overlying the Eocene-Oligocene sequence in the area south of the fault are the continental Sespe formation (Eocene to Miocene) in the east and the transgressive Vaqueros sandstone (Lower Miocene) in the west. All formation contacts within the Lower Tertiary sequence are transitional and conformable. The Anita, Sierra Blanca, Juncal and Cozy Dell Formations are dominantly shale. Within the Juncal is the major Camino Cielo Sandstone member. The Camino Cielo member occurs as three major sand accumulations, each of which grades laterally into dominantly shale and siltstone. Folding discussed previously coincides with areas where the sand is minimal. Sandstone makes up the bulk of the Matilija and "Coldwater" Formations. The lateral and sequential arrangements of facies provide strong support for the lithostratigraphical correlations presented here. Further support comes from the palaeontological age data. We correlate formations with the type sections established by Kerr & Schenck (1928) and Page et al. (195 i). Revisiom to present published correlatiom are as follows. We sprit the Anita of Dibblee (195o) and Kelley (z943) , from bottom to top, into a sub-Sierra Blanca restricted Anita Shale Formation, the Sierra Blanca Formation, and the lower Juncal Formation. The "Matilija" Sandstone and Cozy Dell Shale of the western Santa Ynez Range, as mapped by Dibblee and Kelley, are respectively the lithostratigraphical equivalents of the Camino Cielo Sandstone member and upper Juncal Shale member of the Juncal Formation to the east. The Sacate Sandstone of Kelley (t943) and

WEST GATO CANYON EAST GAVIOTA SANTA YNEZ PEAK GIBRALTARROAD WHEELEREAST S/:~INGS i !E oJt~oO~~~~: .o~o%O.O .o~o~~~..-._.T ~5::::::i::i::i:-i::i:-iii:iiiiiiiil;iiiiiiiii-iiii::::i::i~::::ii:: ,/: v,~:~

MIOCENE ~COLDWATER*FORMATIoN~VAQUEROSFM ~/~,_. '' ":':':':::ii~ii?ii ii:i:ii:!:::::::':'"" ' ~-'~i ~ OLIGOCENE REFUGIAN

COZY DELL FM UPPEREOCENE NARIZIAN F ~:: MIDDLEEOCENE : WITH C AMINO ULATISIAN SANDSTONE MEMBER LOWER EOCENE PENUTIAN SIERRABLANCA FM PALEOCENE BUUTIAN "Yt~Z~

CO NTIN EN TA L 0 K4m"'%'~~//////////'/72~~~~~'z 150 SHALLOW MARINE 300 ~ PROXIMAL TURBIDITES ~550~ TURBIDtTE SAND PACKAGES f , I I TURBIDITES AND MARINE LUTITES Meters ---- TIME ZONE BOUNDARIES F xo. 2. Lithofacies--time diagram showing the distribution of each facies in formations and time.

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Dibblee (I 950) is correlative with the type section of the Matilija Formation. The lower Gaviota Shale of Kelley (1943) correlates with the Cozy Dell Formation to the east. Sandstones of the Gaviota and Alegria Formations correlate with the "Coldwater" Formation to the east. These correlations agree with those of Bailey (I952) and Stauffer (i967a). Bandy & Kolpack (I963) used the formation terminology of Dibblee (I95O , 1966 ) and thus show age disagreements with our work. When the correlations are corrected to our usage, there is general agreement on'ages although we call the "Coldwater" Oligocene and Bandy & Kolpack (1963) place it in the Eocene. We have not resolved this discrepancy.

2. Description and interpretation of lithofacies

Five mappable facies were recognized. They are turbidite and marine lutite facies, proximal turbidite* facies, shallow marine facies, coastal facies, and continental facies. The continental facies (Sespe formation) was studied in some detail by McCracken (I969) and Flemal (I967). The continental facies is not discussed here.

(A) THE TURBIDITE AND MARINE LUTITE FACIES Lithology. Th~ facies (Fig. 3) consists dominantly of siltstone and shale. Very thin to medium bedded graded sandstones may comprise as much as 30 percent of the lithology. These sandstones occur as isolated beds or as groups of beds with a variety of bedding thickness trends within themselves. The very thin to thin bedded shales and siltstones are structureless to finely laminated. Some siltstones are graded and display the same characteristics as the graded sandstones which, with some siltstones, are well graded, laminated or small scale cross-bedded, and normally have sharp, often erosional, basal contacts. Sole marks are abundant and of great variety including flutes, grooves, dendritic ridge molds, skid marks, tension crack fillings, frondescent marks, and burrows (Fig. 4). Size and character of sole marks is not related to bedding thickness. Shale and siltstone clasts are incorporated in single beds. Plant debris is ubiquitous and a few thin coals are present. Burrowing is a common feature of these rocks. Burrows are generally confined to tracks preserved on bed soles or to very small, dominantly horizontally-oriented burrows in the upper parts of beds. Internally, the graded sandstones exhibit some combination of those structure intervals typical of a turbidite as described by Bouma (I962). Nowhere was the idealized sequence seen (Fig. 4). The most commonly repeated sequence is an 'A, B, convoluted B' sequence. One ripple bedded interval was observed.

* The term "proximal," as used here, is genetic in the sense that it places the thick bedded turbidites closer to the source of sediment than are the laterally equivalent thinner bedded turbidites--where such lateral equivalency is demonstrable. The term is descriptive in the sense that it refers to a particular assemblage of sedimentary structures which are characteristic of these thick bedded sandstones.

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Fauna. Microfauna are the main faunal element in this facies. Megafossils, probably displaced, are few and generally fragmented. Sparse well-preserved oyster remains are present. Abundant shark teeth were found at one locality. The microfauna indicate that outer neritic to bathyal depths prevailed during deposition of this facies. Distribution. This facies has widespread occurrence in time and space in the area. It makes up much of the Anita, Sierra Blanca, Juncal, and Cozy Dell formations (Fig. 2). Laterally, some of these very thin to medium bedded sandstones can be traced into progressively thicker

DESCRIPTION bedded sandstones which also 30-- SILTSTONE, BEDDING POORLY display turbidite structures DEFINED DUE TO VERY EXTENSIVE BURROWING. (Proximal Turbidite Facies, below). This relationship is well developed in the Juncal formation. In the upper Cozy Dell

THIN, LAMINATED SILTSTONE Formation these thin bedded AND SHALE. sandstones pass laterally into shallow marine sandstones. FINE GRAINED. MOOERATELY SORTED gRADED SANDSTONE WITH SOLE MARKS. Interpretation. The structures in the graded sandstones and siltstones indicate deposition 20- THIN BEDDED SILTSTONE AND SHALE SOME from turbidity currents while SILTSTONE BEDS ARE GRADED, HAVE RIPPLE CROSS-LAMINA- the fauna indicates deposition TION, AND SOLE MARKS. at outer neritic to bathyal depths. The lime mud facies of Johnson (I968) corresponds to carbonate mud turbidity current FINE TO MEDIUM GRAINED, MEDIUM BEDDED, GRADED position in this facies. SANDSTONES.

FINE TO MEDIUM GRAINED, MEDIUM BEDDED, GRADED SANDSTONES. 10-- POORLY SORTED, SANDY SILTSTONE.

THIN SILTSTONES WITH FEW FINE SANDSTONE INTERBEDS.

LEGEND ~FINE TO MEDIUM, MEDIUM TO .... THICK GRADED SANDSTONES. GRADED AND NON- GRADED VERY THIN TO MEDIUM BEDDED SILT- STONES, AND SHALES. "0" BURROWS GRADED BED FIG. 3. 7/- SOLE MARKS Schematic section of bedding character and features in the Turbidite and Marine Lutite facies. (Scale O I.. in metres).

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(B) THE PROXIMAL TURBIDITE FACIES Lithology. The Proximal turbidite facies is dominantly sandstone, with variable amounts of interbedded siltstones and also some minor interbedded conglomerates (Fig. 5)- Bed thickness generally ranges from 0. 3 to 6 rn with composite beds as thick as 15 to 2o m. Sandstone packages are tens to a hundred or more metres thick. The basal contacts of beds with underlying siltstones or shales are normally abrupt and the few observed gradational contacts are with deformed (commonly chaotically) siltstones and shales (Fig. 6). Sole marked basal surfaces are abundant (grooves, flutes, frondescent marks, burrows, skid marks) and smooth planed basal surfaces are common. The upper contacts of the thinner beds in this facies are commonly gradational; thicker beds have abrupt contacts with overlying siltstones and shales. These contacts may be planar or irregular; the latter due to load pockets or convolutions. Conglomerates have thickness and contact relations similar to the sandstones. Pebble sorting is generally poor and clasts up to 60 cm in diameter may occur in an otherwise finer unit. Cut-and-fill structures are common. Conglomeratic beds commonly have a thin basal and top sand layer. Beds are rarely graded. Internally, the sandstones display a vertical sequence of structures (Fig. 6).

IDEALIZED TURBIDITE TURBIDITE STRUCTURE SEQUENCE STRUCTURE SEQUENCE (AFTER BOUMA, 1962) SANTA YNEZ RANGE

CONTACT LAMINATED PELITIC DIVISION MMONLY SILTSTONE AND SHALE "E" DEFINABLE

UPPER DIVISION OF CONVOLUTED //;COMMONLY A|SENT fill 'zr~ PARALLEL LAMINATION "D" LAMINATED

DIVISION OF CURRENT --- ~~ -~

" L-S,tiSiONE CLASTS" ." "

PARALLEL LAMINATION DISH STRUCTURES (rare) IIBII

.... a." "A'~

• . ." • - "" - "o • . . . ".. • . .. '...." i"~" • • ~. - . . ". • • . " -~.~. • . • • . . . • . .- • . .. • .'.. • . • • . . . .~ STRUCTURELESS ..., . GRADED DIVISION "" ." • • " • uu- • .. -...... ,,A,; • . ° • . . . • "." " .~.~b .... 3. "Al' . . ,.... • . -. • . .." .... .:-.. .'. • ..;

• • -- • . . • . . • • . •

• . . • •

• . . . • . . • .... e.. ; . • . • ..... :- ..e • ...... • • . •'.- . . .- . .- . ..-.. • ...... - • . . .

DIRECTIONAL SOLE MARKS BURROWS

FZG. 4- Comparison of Santa Ynez Range turbidite structure sequence to Bouma ( z 962) sequence.

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Differences in vertical structure sequences in the two proximal turbidite types are summarized at the top of the facing page. Grading is most pronounced in the B intervals. The A interval may display some grading upward from a pebbly base. Silt, tone and shale clasts are common and range up to 1½ by 3 metres in cross section. Laterally discontinuous parting planes are common in some beds and may

MATI L! JA, COZY CAMINO C IELO DELL FORMATION SANDSTON ES

LITHOLOGY GRAIN DESCRIPTION LITHOLOGY GRA I N DESC RIPT ION SIZE SIZE

30-- •m • rn MASSIVE,GRADED SANDSTONE WITH FEW PEBBLES AT BASE, DISH STRUCTURES COMMON, MASSIVE. WELL SORTED. • CONVOLUTELAMINATIONS AT TO COARSE GRAINED TOP. CARBONATE CEMENTED SAND~;TONE WITH BILTITONE AREAS 0~ODULES)COMMON CLASTS AT BASE. lilL'ri'TOlIE 4b V¢ (INDICATED BY SHADED AREAl BED FRAGMENTS IN SHEARIO SOLE MARKS CENTRAL PART OF BLED. If THIN GRADED SlLTSTONES WITH CONVOLUTED LAMINATIOi~ FEW THIN SANDSTONE BEDS AT TOP, SOLE MARKS. COMPLETE BED. • fll THICK. GRADED SANDSTONE C LAMINATEDTOP PORTION SOLE MARKS C THICK. NON-GRADED SANDErOI'ilIE

,.--e f-m • MASSIVE,GRADED S~,NDSTONE WITH DISH STRUCTURES AND IIF~ C'VC LAMINATED AND BURROWED ")v. @m-c UPPEB PORTION. SOLE MARKS MASSIVE, POORLY GRADED em-f O SANDSTONE WJTH LAMINATED 20-- UPPER PART. SHEAR? PLANES MASSIVE. GRADED SANDSTONE' IN LOWER PART AND CARBONATE PEBBLES AND SILTSTONE CLA,$T$ CEMENTED NODULES (SHADED O AT BASE. ABUNDANT DISH AREA) STRUCTURES AND VERTICAL DEWATERING TRACKS. UPPER PART OF BED IS LAMINATED O AND CONVOLUTED. BURROWS • IN UPPER PORTION, PLANT -)V" ®f-m .0. MASSIVE, POORLY GRADED. WELL- FRAGMENTS COMMON NEAR SORTED SANDSTONE. SILTSTONE SOLE-MARKED BASE, • CLASTS ABOVE EROSIONAL BASE

•m-c • m-c SAND-ON-SAND CONTACT (IN PART) e ¥C

MASSIVE, NON~IRADED, STRUCTURELESS SANDSTONE WITH CARBONATE CEMENTED NODULES (SHADED AREA) • m-c T THIN--BEDDED,GRADED SILTSTONES O f THIN TO MEDIUM. GRADED SILTSTONES WITH FEW THIN- 10-- • f-fiR MEDIUM SANDSTONES ~s ",®m O • vc t9" of @m O , Do 5-- @ @m @m-c Ovc

• m-c THICK-BEDDED SANDSTONES, (~ C THICK COARSE SANDSTONE GENERALLY STRUCTURELESS. WITH LOWER PART OF BED I) 111 SOME SOLE MARKS CEMENTED BY CARBONATE T of

• m 0.mpm

LEGEND

BURROWS ~ SOLE MARKS C~ PLANT REMAINS :-:-:..GRADED SANDSTONE GRADED AND NON-GRADED VERY THIN TO MEDIUM BEDDED SILTSTONES AND SHALES.

Fro. 5. Schematic section of bedding character and structures in the Proximal turbidite facies. Examples for both the Camino Cielo and Matilija types are shown. (Scale in metres).

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* Dish structures (Wentworth, I967; Stauffer, I967; Corbett, 1972) are concave-up, dish profiled structures. Higher dishes truncate lower dishes. The ratio of depth to width ranges from o.o2 to x.o. See Figs. 5 and 6. or may not be related to laminations in a particular bed. Chaotic slumping, and in some cases recumbent folding, is well developed in some beds. Vertical and horizontal burrows may occur in the B~ and B~ intervals. Large festoons (t o m long), each with their own related dish structures, are common in many beds. Vertical, wavy, tubelike structures (dewatering tracks ?) are commonly observed in dish- structured beds. This feature is similar to the dish structures in 'liquified' intervals described by Kruit et al. (t 972) in Spain. The Proximal turbidites are much like those described in Wales by Kelling & Woollands (T 969) as their facies B. These Welsh turbidites (facies B) also contain well developed dish structures.

CAMINO CIELO TYPE / MATILIJA TYPE SHARP CONTACT LOAD POCKET I BURROWS _ /F~TF. " ...... ~ o~ __ N BI~ ~ ~-~

~,...... ,..~,:_.,.._~ .~-- ,_. ,---I I I ~,_.~-~L'-CA"I~EOUS~ "~ DE-WATERING/~----~ I

~----,,,,.~"-NOD,~ULE ~_~-Q'---~TRACKS~,,_~[ C'~"~ALC'~REOUS NODULE I

I ~-~-,~~'~I~H'~T'~UUC'~U~RES---,.._.~'-C'~-,.~'--~~" ~-DISCONTINUOUS PARTING PLANE.c I m A 2 ~:."-~--~----~ ~ AND ~"~~- ~.---:--'~' .... I ~>-, -~__~.:._,,.._ ,..._~.~~_C -~_.I ~.-_-~._;~~__~ ~ "'~ ~ ~---~-~-"I ::. I I

" ._~,____'--~-_.T_.'-~.--~__~,,-~-- ~-- ~'-----~ I Z "~~~~ISH STRUCTURES~.--1

• ...... _...... :.:: -.':-... "--:..

STRUCTURELESS .. I (TO LAMI NATED) "'. I AI ~21_.~ =~.-'"" ~.,-,~., ~ . I:,~*"""~ "'...

< SAND )' SHARP CONTACT II[LATIV[ GIIIAIN|!z| AND/OR PEBBLES I SOLE MARKS -- COMMON TREND

...... PO551BLE rR( ND FIG. 6. Schematic diagram of structures and features of proximal turbidite bed sequences in the Camino Cielo and Matilija types. In both cases, sediment transport was from left to right.

Downloaded from http://pubs.geoscienceworld.org/jgs/article-pdf/130/6/545/4884852/gsjgs.130.6.0545.pdf by guest on 27 September 2021 554 P. C. van de Kamp et al. Fauna. Rare megafaunal remains in this facies are highly fragmented. Excep- tions to this are locally abundant and well preserved Turritella sp. gastropods. Oyster fragments comprise the major portion of the transported debris. Micro- fauna, the main faunal element, indicate upper bathyal to outer neritic water depths. Distribution. The Proximal turbidite facies is represented by the Camino Cielo sandstone member of the Juncal, the lower Matilija formation and the Cozy Dell sandstone, and occurs locally in the "Coldwater" formation. In two dimensions, this facies is lenslike. In the Camino Cielo member, there are three major lenses along the length of the Santa Ynez Mountains. These are up to 6oo m thick and 15-2o km long. These dimensions are similar to those for the deep water fan deposit described by Kruit et al. (1972). Laterally with transition into the turbidite and marine lutite facies, bedding thins, the proportion of shale and siltstone increases, and the abundance of graded beds increases. The Proximal turbidite facies of the Matilija formation passes vertically into the Shallow Marine and Coastal facies. Interpretation. The information cited above suggests that these sediments were deposited from turbidity currents in outer neritic to upper bathyal water depths. The lateral transition from thick-bedded, coarser grained to thinner bedded, finer grained sandstones (turbidite and marine lutite facies) suggests that the former were in a more proximal position to the source area than the latter, hence, the name proximal turbidite (Walker, I966 ). The vertical transition from turbidites and marine lutites, to proximal turbidites, to shallow marine and coastal sediments indicates a regressive interrelationship between facies (see Depositional history). Similar sequences have been recorded elsewhere by Walker (I966). These rocks were interpreted as grain flow deposits by Stauffer (I967b). In the terminology of Middleton & Hampton (I973) we classify the sand deposits as sediment gravity flows of the turbidity current, fluidized sediment flow, and grain flow types. The conglomerates may be grain flow and debris flow type deposits.

C) THE SHALLOW MARINE FACIES LithologT. The Shallow marine facies is characterized by three distinct lithologies" (i) sandstone with oyster lenses; (ii) sandstone with algal bank; and (iii) cross- bedded and slumped sandstone. Details of this facies are illustrated in Fig. 7- (i) Sandstone with oyster lenses. This lithology is characterized by the abundant occurrence of conglomeratic oyster-rich lenses interbedded with thin to thick bedded, fine to medium grained sandstones and sandy siltstones. The oysters average from lO-15 cm in length and range up to 2o cm. "In situ" oysters are commonly articulated. Considerable skeletal debris, churn and vertical burrowing, cross stratification, horizontal laminadon, and scour channels are present. (ii) Sandstone with algal bank. This lithology consists of the sandy, algal bank and carbonate breccia facies as defined by Johnson (I968) for the Sierra Blanca formation. The sandstones contain greater than x5% of terrigenous grains and sparse miliolid foraminifera. The thin to very thick bedded, fine to coarse grained,

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poorly sorted sands contain quartz, feldspar, bryozoan fragments, algae, forams, and echinoid and oyster debris. Structures present include cross-bedding, burrows and scour contacts. Algal bank lithologies contain greater than 5 ° % of branching calcareous algae with lesser amounts of bryozoans, forams, echinoid debris and terrigenous material. The carbonate breccias consist of fragmented skeletal debris and less than 2o% of calcareous L I THOLOGY GRAIN DESCRI PTION algae. SIZE 6 O ---= OYSTER REEF, COMPLETE ~~~'~,~¢ VALVES IN PLACE, ABUNDANT (iii) Cross-bedded and slumped xS P s sandstones. This lithology displays

MASSIVE SAND. LOW ANGLE features which are a mixture of CROSS-BEDS ~ REO AND GRAY GREEN those seen in the Proximal tur- ~~ m-c o SILTSTONES WITH LIMESTONE bidite facies, the Shallow marine facies and the Coastal facies. 50 - L SEGUENCE COARSENS The sandstones are thin to thick bedded and fine to medium grained. Cross-bedding, abundant horizontal lamination, SILTSTONEI CHURN BURROWED

OYSTER BEDS IN SILTSTONE churn burrows, ophiomorphid em and other vertical burrows, and 40 - MASSIVE SANDSTONE COARSENS UPWARD, MEDIUM scour channels are present. O f TO LARGE SCALE CROSS 2C BEDS-MOSTLY LOW ANGLE. Cross-bedding is less abundant SHELL LAGS. BURROWED SILTSTONE, here than in the Coastal facies. THIN-BEDDED Also present are sandstones with OYSTER REEF WITH COARSE, GRAVELLY SAND MATRIX. contorted bedding, minor grad- 30---- •m-f MASSIVE SANDSTONE WITH ing, siltstone and shale clasts MEDIUM TO LARGE SCALE CROSS-BEDS, PEBBLE LAGS, and minor convolutions. Plant CUT AND FILL STRUCTURES. OC remains are ubiquitous. The distinguishing character- SILTSTONE AND SANDY SI LTSTONE, BURROWED istics of this lithology are the ef 20 -~- association of cross-bedded and channelled sandstones with con- ef voluted and slumped sandstones.

• m MASSIVE SANDSTONE WITH MEDIUM TO LARGE SCALE CROSS-BEDS, PEBBLE LAGS, SILT CLASTS, QUARTZ ®c 10-- PEBBLES, WOOD FRAGMENTS, CUT AND FILL STRUCTURES. • m SEQUENCE BECOMES FINER UPWARD. SMALL SCALE CROSS-BEDS NEAR TOP.

m ec FIO. 7" Schematic section of Shallow marine and Coastal facies bedding and structure features. (Scale in metres.) LEGEND

'~- BURROWS ~ PLANT REMAINS ~] THIN TO MEDIUM BEDDED SILTSTONES

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Fauna. Megafaunal abundances are variable throughout this facies. Jestes (locality 426% Matilija formation, t963) obtained 23 specimens which he inter- prets as having undergone no significant lateral transport. In this assemblage there are I2 pelecypod, I O gastropods and t scaphopod species. TurriteUa sp. are generally present. The microfauna, where significant, is neritic (Fig. 8). Distribution. The shallow marine facies is present in the Matilija and "Coldwater" formations (Fig. 2). The sandstone with oyster lenses lithology is the main representative of this facies in the "Coldwater" formation west of Santa Barbara (Fig. 1). Strati- graphically, it occurs in a transitional position between the coastal facies of the "Coldwater" formation and the turbidite and marine lutite facies of the Cozy Dell formation. The sandstone with algal bank lithology is confined to the Sierra Blanca formation. The cross-bedded and slumped sandstones lithology comprises the Matilija-equivalent of the shallow marine facies and is in a transitional position between the Proximal turbidite and the Coastal facies of that formation.

LI T HOLOGY AGE FORMATION FACIE S WATER DEPTH 0 3100 600 12(30 METERS S E S P E N O N M AR I N E NERITIC BATHYAL • | i I "COLDWATER" C O A S T A L UPFE:RIM~Ot'E OLIGOCENE SHALLOW MARINE -" j 1 C OZY TURBIDITE AND I UPPER EOCENE D E L L MARINE L UTITE I

--, L SH ALLOW /~..ARINE MATILIJ A C OA S TAL SHALLOW MARINE MIDDLE PROXIMAL TURBIDITE

EOCENE TURBIDITE AND MARINE LUTITE JUNCAL PROXIMAL TURBIDIT E I

"' E IRRA "" " ' PALEOCENE ANITA TUBIDITE AND MARINE LUTITE UPPER J ALAMA CRETACEOUS [ ] SANDSTONE I s.AtE F to. 8. Generalized diagram of facies and bathymetry data. Bathmetry is from faunal assemblage interpretations.

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Interpretation. The abundance of "in situ" shallow marine megafauna, the occurrence of shallow marine (neritic) foraminifera, and the high degree of bioturbation and physically reworked sediment indicate deposition of this facies in a shallow marine environment. The sandstone with oyster lenses lithology represents a shallow marine, terrigenous clastic, marine 'shelf' deposit. Lateral facies relationships with the coastal facies suggest these sediments were deposited very near to coastline (commonly within I km). Physical reworking of sediments provided a sufficiently stable substrate for colonization by oysters. According to Johnson (I968), comparison of the sandstone with algal bank lithology with a Recent analogue in the La Paz, Baja California area suggests deposition in water I o to 4 ° m deep, in an area of strong currents. The bank core was flanked by considerable carbonate debris, this debris mixed with terrigenous sediment being deposited in the environs of the bank. The calcareous algae and associated corals suggest a tropical to subtropical climate. The cross-bedded and slumped sandstone lithology represents a zone of transition between the Coastal facies and either of the Turbidite facies, hence, the mixture of structure assemblages. This lithology is best developed when transitional to the Proximal turbidite facies. It exhibits the first real evidence of slumping and instability, at the same time as the sediments were under the influence of wave and current activity. (D) THE COASTAL FACIES Lithology. Lithologic diversity characterizes the coastal facies (Fig. 7). Two lithologic trends observed are (i) coarsening-upward trends, and (ii) fining-upward trends; various composites of these two sequences are common. (i) Coarsening-upward treruts. The most common trend encountered in this facies is, from base to top, highly churn burrowed sandy siltstone, vertically burrowed and laminated silty sandstone, horizontally laminated and cross-bedded sandstone with a few pebble lags. Oysters of much smaller size than those in the shallow marine facies occur as lenses between the churned and the vertically burrowed portion of the sequence. The number ofbeds having scour contacts and local pebble lags increases upward. Lacking megafaunal support, recognition of the transgressive or regressive nature of such a sequence can be based upon the presence or absence of interbedded red siltstones, lime mudstones, bedded gypsum and rare mudcracks. Coarsening-upward sequences are as thick as IO m. (ii) Fining-upward trends. The most common fining-upward trends are those having erosional basal contacts with pebble lags, that pass upward into structureless, laminated, or cross-bedded finer grained lithologies. Some burrowing occurs in such sequences. Fining-upward sequences are as thick as 3-4 m. A second fining-upward trend observed is simply the reverse of the previously described coarsening-upward trend. Recognition of distinct, complete trends is commonly not possible. Parts of sequences are combined in numerous ways. Such complexity requires that definition of the facies be based upon general facies characteristics" medium to very thick bedded sandstones; medium- to large-scale, low- to high- angle cross-bedding; tipple marks; lamination; the variety of burrow types and

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their sequential relationship; the abundant megafauna; the interbedded red siltstones. Fauna. The magafauna of this facies are diverse. Oysters are a ubiquitous element, although much smaller and thinner shelled than those encountered in the Shallow marine facies. Jestes (I963) identified a large suite of faunal types. The microfauna is sparse and includes the foraminifera Elphidium sp. and ostracods. Distribution. This facies occurs in the Matilija and "Coldwater" formations. In both it is underlain or is laterally equivalent to the shallow marine facies. It is overlain in the Matilija formation by a transgressive shallow marine facies; in the "Coldwater," by the nonmarine Sespe formation. Interpretation. The presence of gypsum, limestone, and red siltstone interbeds, a shallow marine fauna whose equivalent in the Matilija formation is interpreted by Jestes (I963) to be restricted or brackish, abundant vertical burrowing, cross- bedding, lamination, erosional contacts and mudcracks, as well as being lateral equivalent to the nonmarine Sespe formation, suggests that these lithologies record former coastal environments where there was some oscillation between continental and marine conditions. The coastal facies represents a complex mosaic of sequences or subfacies (Laporte I967) superimposed upon the more general regressive trend of shallow marine to coastal and continental facies. 3. Depositional history In the area of the western Santa Ynez Mountains only, Tertiary sedimentation commenced in the Paleocene with the deposition of turbidites and marine lutites (Anita formation) in a bathyal basin (Fig. 2). Sedimentation continued uninterrupted into the Lower Eocene although a marked change in sediment distribution and type characterized this period. In the Santa Ynez Range silty lime mud and limy silt turbidites (Sierra Blanca Forma- tion) were derived from shallower marine algal banks north of the study area. In the western Santa Ynez Range these turbidites interfingered with foraminiferal- rich terrigenous lutites (the Poppin Shale ofDibblee 195 o) whereas to the east they were deposited disconformably directly upon Upper Cretaceous turbidites. This eastern contact is characterized by scattered pebbles of possible Cretaceous lithology in a calcareous, glauconitic, fine sandstone of probable turbidite origin. Vertically this sandstone interval is followed by typical lime mud turbidites. Water depths during this time ranged from outer neritic in the east to upper bathyal in the west (Fig. 8). This interval of carbonate sedimentation was followed uninterrupted by a marked increase in terrigenous influx into the basin (Juncal formation). Terri- genous thin bedded turbidite and marine lutite sediments were deposited over earlier carbonate-dominated deposits and were followed closely in time by thick accumulations of thicker bedded proximal turbidites (Camino Cielo member). Upper bathyal water depths existed throughout the study area although there was greater subsidence, as evidenced by the thicker section in the east. The proximal turbidite bodies evidence three main accumulations of sand, each of which passes

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laterally into sections dominated by thin bedded, well graded turbidites and marine lutites. Paleocurrent directions in these sand bodies (Fig. I) indicate a variety of directions, of which westerly to southerly directions predominate. Conglomerates were contributed to the basin locally, at points corresponding to the sections of greatest sand accumulation (Fig. 2). The character of these conglomerates (thickness, boulder size, sorting) suggests that they represent close proximity to influx points. By the end of the Middle Eocene there was a general decrease in sand influx. This decrease continued during the early part of the Upper Eocene with deposition of thin bedded turbidites, marine lutites, and associated proximal sand and conglomerate. Throughout this whole period of proximal turbidite sedimentation the sands show a gradual improvement in sorting. Finally marine lutite and minor distal turbidite sediments were deposited throughout the area. Subsidence throughout this period continued to be greatest in the east and bathyal water depths still prevailed. Following this period of relative quiescence, a major period of clastic influx (Matilija) occurred which led ultimately to progradation of shallow marine to continental sediments throughout the study area. Subsidence in the east continued to be greatest. Proximal turbidite deposition in upper bathyal depths kept pace with this eastern subsidence. Westward, more stable tectonic conditions resulted in a much thinner sequence and only minor accumulation of proximal turbidites. West of Gaviota Pass the occurrence of a predominantly proximal turbidite sequence, in conjunction with the local occurrence of conglomeratic, sand-filled channels, the stratigraphic relationship of the underlying Camino Cielo proximal turbidite package, and meagre NW-SE paleocurrent data, is interpreted as suggesting a northwesterly to northerly source for these deposits. Progradation of shallow marine and coastal sediments probably resulted from a decrease in the rate of subsidence for there is no evidence of an increase in the rate of sedimentation. This brought the earliest Eocene regressive episode (Juncal-Matilija) in the Santa Ynez Mountains to completion. Link (I 972) has a similar interpretation of the Matilija in the eastern Santa Ynez Mountains. Marine transgression gradually terminated Matilija sedimentation throughout the area. Sands in the east underwent considerable physical reworking, as might be expected in a transgressive situation. Continued dominance of submergence over sedimentation resulted in the establishment of outer neritic to upper bathyal water depths over former shallower water environments (Fig. 8). Thin bedded turbidite and marine lutite deposits (Cozy Dell formation) accumulated during this transgressive phase of the newly formed basin, the former representing a significant percentage of the deposits. The Cozy Dell proximal turbidites suggest the possibility of minor fluctuation in either the rate of sedimentation or the rate of subsidence resulting in some coastal progradation. The last stage of development of the Santa Ynez Range sequence was recorded by the initial accumulation of marine lutites (Cozy Dell formation) with some minor thin bedded turbidite influx in outer neritic to upper bathyal depths (Fig. 8). This second regressive episode of deposition (Cozy Dell-Sespe) resulted in gradual shallowing of the basin with only minor proximal turbidite deposition. The transition is characteristically one of deeper marine lutites to shallower marine

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sands ("Coldwater" formation). Again marked decrease in subsidence or increase in sediment supply resulted in major progradation of shallow marine to continental environments. Coastal plain, braided stream and alluvial fan deposition dominated by the end of Oligocene time, reflecting major tectonic uplift of source areas. Summary The Eocene-Oligocene section of the Santa Ynez Mountains records the intimate interrelationship between rates of sedimentation and rates of submergence as the result of tectonic adjustments in the basin and surrounding area. In seaward sequence, the sedimentary facies developed were continental, coastal, shallow marine, thin and, or, thick bedded (proximal) turbidites. A zone of transition between shallow marine sediments and turbidites is characterized by cross-bedding, slumping and contortion. In some cases the turbidites occur as very thick bedded sand layers proximal to shallower sands displaying considerable contortion. These layers thin distally. In other cases the turbidites occur only as thin bedded sand layers proximal to shallower sands displaying only minor contortion. The turbidites pass laterally into basin muds. 4. General palaeogeography Regional correlation within the western Transverse Ranges, of which the Santa Ynez Mountains are a part, is complicated by lateral and vertical fault movements, many of which have unknown displacement. We have correlated between fault blocks with microfaunal data (Table I). North of the Santa Ynez Fault, much of the Mutau formation (Juncal equivalent), and the Thorn Meadows and Derrydale formations (Matilija equivalents), are shallow marine and deltaic deposits with many paleocurrent directions trending south and southwest into the area of the Santa Ynez Range (Jestes 1963). In the eastern Santa Ynez Mountains, Eocene-Oligocene sediment transport was from east to west with local variations such as the south to north directions in the area northwest of Ojai (Fig. I). The "Coldwater" formation, south of the Santa Ynez Fault, was deposited by westward flowing currents. North of the fault, this interval has similar paleocurrent directions. This information suggests that the main source of sediment and the shoreline throughout the Eocene and Oligocene were east and northeast of the study area. With the exception of the westernmost Santa Ynez Mountains (Fig. I), there is no evidence of major western sediment sources. O'Brien (1972) also cites evidence for another source for some of the western Santa Ynez Mountains Eocene sediments. The deep, open basin of Eocene time was to the south and west of the present Santa Ynez Mountains outcrop belt.

5. Sedimentological processes The present study provides the following hypothesis of turbidite sedimentation. Fluvial sediment supply to a basin leads to construction of a delta complex on the basin margin. Progradafion of the delta into deeper water results in its submarine

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profile becoming increasingly unstable. Instability occurs initially in the topmost (coastal) part of the slope where sand normally predominates. Consequently, mass movements on deltaic slopes prograding in shallow seas will probably include a high percentage of sand; there may even be sand continuity from coastal-deltaic sands down into proximal turbidite sand bodies. Slope instability is considered to be a function of shear strength of the slope sediments, of slope angle, and of slope length. Stated in more general terms, progradation of shallow marine and coastal sediments into progressively deeper water can lead to development of instability at the point of break in slope; the areas of highest rate of sedimentation (deltas or fans) exhibiting the greatest sediment instability. Lesser degrees of instability would be associated with lower rates of sedimentation. Sediment instability would be reflected by slumping and turbidity current generation. In seaward sequence, the resultant distribution of facies would be continental, coastal, shallow marine ("shelf"), turbidites ("slope"), turbidites and lutites (basin floor). Sand accumulation would be dominant along basin margins. Thus the resultant stratigraphical sequence is a response to the particular characteristics of a basin such as basin configuration, basin history, shelf width, slope angle and origin, rate of sedimentation, location of point sources, and basin tectonics. In the case of the Eocene- Oligocene section in the Santa Ynez Mountains, three variations (types) of basin setting interrelationship have been interpreted. Type I. This had slope instability of imignificant degree for proximal turbidite generation (Fig. 9). This type, represented by the "Coldwater" sandstone, is characterized by delta and interdeltaic coastal progradation in sufficiently

-_ ..... w ".7.-'"-'" .

TURBIDITE ... -

_,-,5\~ \~ /I .... t MARINE LUTITE ~D~y~.f J ~ JJ

/ /

.~ I ~J~ TURS~D,TE S.NDS " "~ AND ~" MARINE LUTITES f ./

F I (3. 9" Block diagram illustrating development of facies sequence under relatively stable basin conditions (Type I). Note the absence of proximal turbidites under these conditions.

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shallow water that the depositional slope remained at a low angle. Here a vertical coarsening-upward sequence from basin muds to prodelta silts to deltaic and interdeltaic sands occurred. Minor slumping at the slope edge gave rise to a few thin bedded turbidites but sand layers exhibiting the characteristics of the thicker proximal turbidites were not deposited. Type 2. This had slope instability as a function ofdepositional processes (Fig. IO). The Matilija formation is interpreted to represent a case where the basin was deep, and slopes were depositional and at greater angles than in the case of Type I. Progradation of a delta into increasingly deeper water led to continued increase of slope length. Instability and consequent slumping of large masses of sediment generated turbidity currents in this zone. Thick bedded proximal turbidites accumulated on and at the base of the delta slope whereas more distal, thin bedded turbidites accumulated on the lower slope and basin floor. The turbidite sands are better sorted than those of Type 3 because they were subjected to considerable physical reworking in shallow marine and coastal environments during delta progradation. Type 3. This had slope instability as a function of diastrophic processes (Fig. I I) This is the least well documented case, for it is not possible to demonstrate either the presence or absence of sand continuity between deep marine proximal turbidites and shallow marine sands. The coarseness of the sand, the poor sorting,

>200 M

.....

MARINE LUTITES J

F Io. 1o. Schematic representation of facies development and distribution in the case of slope instability as a function of delta building into progressively deeper water (Type 2). Shallow marine sands (A) slump into deeper marine environments (B). This can result in the deposition of sand in environments ranging from bathyal to continental.

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the occurrence of large sedimentary blocks (I~ X 3 X ? m), and boulder conglomerates of local distribution are interpreted to indicate that slopes were steep. Some of the more poorly sorted conglomeratic turbidites are possibly the products of direct underflow of marine waters by high density sediment-laden, fluvial waters. The availability of conglomeratic material suggests a high gradient and possibly narrow deltaic plain. The outer margin of the delta would possibly be in a condition of continued instability resulting in mass movements down submarine canyons, thereby bypassing a possible nondeposifional slope, as in Recent basins off-shore of California. Thick bedded turbidite sands (proximal turbidites) would accumulate on and at the base of the slope to form a submarine fan. Thin bedded, more distal turbidites would accumulate basinward of the main body. Initally, no connection would exist between turbidites and shallow marine or coastal sands. However, continued basin shallowing could lead to establishment of such a connection and ultimate evolution to deposifional Type 2 (Fig. :o). From the foregoing it is evident that the stratigraphical sequence in a basin reflects the influence that basin character exerts on sedimentation. The character of the turbidites will vary primarily as a function of the amount of sediment available. Thus small slumps would lead to thin bedded turbidites which thin distally. Larger slumps would yield thicker bedded turbidites, also thinning laterally.

.~- _-=--- ~

> 200 M -TIME LINE A \ /

"x £ -.~ /" "x ~--CONG"OMERL ATE S I \ ~' ~'

I r /

.._ \ TURBIDITE SANDS ~ [ k ~ ~ _.~ I AND ~ ~ J MARINE LUTITES ~" ~ ~. \ \ \ I L f

F xo. x I. Schematic illustration of facies distribution in the case (Type 3) of slope instability resulting from diastrophic processes. In this example, the proximal turbidites are separated from shallower marine sands by a nondepositional slope.

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Delta advance may decrease in rate, or even stop, as a result of the advance into deeper water depths or as a result of diastropic processes. Further advance would require the transfer of sediment from shallower into deeper waters to build up a base for such advance. Turbidite sedimentation is the process whereby such buildup would occur. The Eocene-Oligocene sequence of the study area provides three examples of sediments deposited in a very wide oceanic basin. In each case, sand accumulation was marginal and the stratigraphical sequence on one side of the basin was unaffected by sedimentation on other parts of the margin. Where there was insignificant slope to the basin floor, proximal turbidites did not accumulate (Type I). When slope instabilities were developed either by depositional (Type 2) or by diastrophic (Type 3) processes, proximal turbidites did accumulate. The present state of knowledge suggests that these examples, as well as those of Walker (I967), represent only a few of the possible stratigraphical sequences that could result from turbidite sedimentation. Narrower basins or greater rates ofsedimenta- t.ion might result in the coalescing of numerous submarine fans or sand bodies such that mainly sand-sized sediment would accumulate in the basin axis. Assignment of greater or lesser roles to point source locations (side entry and end entry) and rates of basin filling would permit a great variety of possible stratigraphical sequences. An understanding of the depositional processes and the tectonic setting of a basin will lead to an understanding of the lithofacies distribution.

ACKNOWLEDGEMENTS.We are grateful to Shell Development Company, for whom this work was done, for permission to publish it. Much useful assistance and discussion were freely given by E. Oomkem. The encouragement and critical comments of W. R. Dickinson are appreciated.

6. References Bnxt~Y, T. L. 1952. Geology of Southwestern Santa Barbara County, California, by T. W. Dibblee, Jr., (Review). Bull. Am. Assoc. Petrol. Geol. 36, 176-x82. BANDY, O. L. & KOLPACK, R. L. x963- Foraminiferal and sedimentological trends in the Tertiary section of Tecolote Tunnel, California, Micropaleontology 9, t x7-17 o. BLAISDELL, R. C. 1956. The Stratigraphy and Foraminifera of the Matilija, Cozy Dell, and "Coldwater" Formation near Ojai, California, M.A. thesis Paleontology, Univ. Calif., Berkeley. Bo~, A. x962. Sedimentology of Some FI.ysch Deposits: A Graphic Approach to Facies Interpretation. Elsevier, Amsterdam, 168 pp. CORB~TT, K. D. I972. Features of Thick-Bedded Sandstones in a Proximal Flysch Sequence, Upper Cambrian, Southwest Tasmania. Sedimentology x9, 99-I I4. Dmalm~, T. W., Jr. 195o. Geology of Southwestern Santa Barbara County, Galifornia. Calif. Div. Mines and Geology, Bull. x5o, 84 pp. ----- 1966. Geology of the Central Santa Ynez Mountains, Santa Barbara County, California. Calif. Div. Mines and Geology, Bull. I86, 99 PP. FIsrmg, R. V. & MATTmSON, J. M. i968. Wheeler Gorge Turbidite-Conglomerate Series California; Inverse Grading: J. Sed. Pet. 38, t o x3-t o23. FLE~AL, R. C. I967. Sedimentology of the Sespe Formation, Southwestern California, Ph.D. thesis, Princeton University, 23o pp. J~sT~s, E. C. 1963. Stratigraphic Study of Some Eocene Sandstones, Northeastern Ventura Basin, California. Univ. Calif., Los Angeles, Ph.D. thesis, 253 pp. JOHNSON, C. J. 1968. Petrography and Paleoecology of the Sierra Blanca Limestone. M.S. thesis, Univ. Calif., Riverside.

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