SMITHSONIAN CONTRIBUTIONS TO THE MARINE SCIENCES • NUMBER 4 

Submarine Canyon Wall 

Sedimentation and Lateral Infill: 

Some Ancient Examples 

Daniel Jean Stanley 

ISSUE D 

FEB1319*) 

SMITHSONIAN PUBLICATIONS 

SMITHSONIAN INSTITUTION PRESS 

City of Washington 

1980 
ABSTRAC T 

Stanley, Daniel Jean. Submarine Canyon Wall Sedimentation and Lateral Infill: 

Some Ancient Examples. Smithsonian Contributions to the Marine Sciences, number 4, 32 pages, 17 figures, 1980.—Submarine canyon wall and tributary sequences 

at three Annot Sandstone localities in the French Maritime Alps record early-stage 

resedimentation events in proximal sectors of the Tertiary Annot Basin. Canyon 

margin lithofacies are distinctive in that they comprise a more variable suite of stratal 

types than intracanyon slope, canyon axis, distal fan and basin series of the same 

formation. Characteristic criteria include the highly variable geometry and spatial 

distribution of the series of strata, irregular bedding thickness, paleocurrent directions that diverge from the predominant regional patterns, and discontinuities within 

the formation and between the Annot Sandstone and the older marine shale series 

(Eocene Marnes bleues) forming the canyon margins. Three distinctive sandstone 

stratification types dominate the "gres d'Annot" canyon wall association: type 1 

units, moderately to well-stratified and massive (often amalgamated), emplaced by 

debris flow and a continuum of sediment-fluid flow mechanism, not specifically identifiable in the field; some thick sand layers may represent deposition as 'quick' beds 

from high-concentration underflows, possibly gradational between liquified and turbidity current flows; type 2 units, displaying slightly to extensive deformed horizons 

within but not throughout the beds, probably are related to liquefied flow and 

post-depositional liquefaction processes; and type 3 units, emplaced 'en masse' and 

in some cases showing complete disruption of primary stratification (chaotic bedding), 

are identified as slides and slumps. In addition to the three above types, lower proportions of graded, generally thin 'classic' sandstone turbidites (Ta_b, Tb.c, and Tb. e ) 

and mudstone turbidites are recognized. 

Although they appear as distinctly different entities in the field, a genetic relation 

between some depositional types is suggested. The mapped fades diversity is interpreted in terms of flow transformation, that is, the release of different sediment types 

along the dispersal path from a single sediment gravity flow as it evolves during its 

progression downslope. The diversity of mass flow products at the three canyon margin 

localities records a variable succession of transformation phases on the relatively steep 

slopes (locally in excess of 10°) within a short distance from the point of initial 

failure. The distinctive aspect of "gres d'Annot" canyon margin sedimentation is the 

repetitive erosion—*transport—^deposition..pattern* oi lateral infill. Definition of these 

proximal lithofacies serves to bet!eF*antlerstand"jjhJ origin of the more distal marine 

fan and Annot Basin plain sequences seaward of the three canyon localities examined 

and also can be applicable to ther|tudy«of. modeEn canyon-fan settings. 

OFFICIAL PUBLICATION DATE is handstamped in a limited number of initial copies and is 

recorded in the Institution's annual report, Smithsonian Year. SERIES COVER DESIGN : Seascape 

along the Atlantic coast of eastern North America. 

Library of Congress Cataloging in Publication Data 

Stanley, Daniel J 

Submarine canyon wall sedimentation and lateral infill. 

(Smithsonian contributions to the marine sciences ; no. 4) 

Bibliography: p. 

Supt. Docs, no.: SI 1.41:4 

1. Marine sediments. 2. Sedimentation and deposition. 3. Submarine valleys. I. Title. II. 

Series: Smithsonian Institution. Smithsonian contributions to the marine sciences : no 4 

GC380.15.S7 551.4'608 79-607075 
Contents 

Page 

Introduction 1 

Acknowledgments 2 

General Setting and Background Information 2 

Observations 3 

General Aspect and Geometry of Canyon Wall Facies 4 

Prevailing Assemblage of Strata 5 

Type 1 5 

Type 2 5 

Type 3 5 

Other Types 6 

Dispersal Patterns 6 

Texture, Fabric, and Microstructure 6 

Interpretation of Dominant Stratal Types ' 

Lateral Infill: Inferences and Discussion 9 

Literature Cited 12 

Figures 15 
Submarine Canyon Wall 

Sedimentation and Lateral Infill: 

Some Ancient Examples 

Daniel Jean Stanley 

Introduction 

The importance of submarine channel systems in 

continental margin sedimentation is generally recognized, but modern canyon facies remain poorly defined and information on proximal canyon processes 

below SCUBA diving depths, more often than not, 

is based on inference rather than on actual observation. There are considerable logistical obstacles in 

obtaining sufficient data: the steepness and topographic complexity of canyon slopes, the narrowness 

of axes and the coarse, dense nature of canyon fill 

sequences have generally accounted for the poor 

resolution of echo-sounding and subbottom records, 

the uneven sample density, and the low penetration 

and inadequate recovery of cores in sand and gravel 

(Shepard and Dill, 1966). Consequently, the nature 

and origin of modern canyon wall deposits and their 

spatial and temporal relation to axial canyon facies 

remain poorly known. Moreover, little is known of 

processes involved during the early phases of downslope transport when sediment fails, is displaced and 

then is redeposited on the steep canyon margin below 

canyon head depths. Workers have long realized that 

it is necessary to bridge this gap to attain a more 

precise understanding of sedimentation in deep environments at and beyond the base of continental 

slopes (Stetson and Smith, 1938; Bell, 1942; Shepard, 

Daniel Jean Stanley, Division of Sedimentology, National 

Museum of Natural History, Smithsonian Institution, Washington, D.C. 20560. 

1951). Knowledge of processes in modern submarine 

canyons is based largely on direct observations in a 

rather limited number of modern settings, and on 

field investigations of possible ancient canyon analogs 

(recent reviews in Whitaker, 1976, and Stanley and 

Kelling, 1978). 

This study focuses specifically on some ancient 

canyon wall deposits and attempts to provide further 

insight on sediment transport patterns in proximal 

channelized settings. Most ancient canyon investigations have described examples from the subsurface on 

the basis of core and seismic data (Almgren, 1978) 

and from surface sequences that are structurally deformed and, in most cases, only partially exposed (see 

examples in Whitaker, 1962; Carter and Lindqvist, 

1975). A noteworthy exception is the well-exposed and 

structurally little deformed Tertiary Annot Sandstone 

("gres d'Annot") Formation in the Maritime Alps of 

southern France (Figure 1). This sequence includes 

thick, massive sandstone belts, identified as submarine 

valley fills (Stanley, 1961), that merge with turbiditerich sequences of intercanyon slope, base-of-slope and 

submarine fan origin (Stanley, 1975). A number of 

"gres d'Annot" outcrops that comprise facies representative of different lower canyon and fan channel 

environments are distributed along major paleoslopes, 

and these exposures enable us to examine the sequential depositional patterns between steep proximal and 

the less steep, more distal, sectors of a continental 

margin and basin (paleogeographic scheme illustrated 

by Stanley, et al., 1978, Figs. 8-16). 
SMITHSONIAN CONTRIBUTIONS TO THE MARINE SCIENCES 

On the basis of this fortuitous distribution of good 

exposures several hypotheses have been elaborated in 

these earlier "gres d'Annot" studies. One pertains to 

the widely held tenet that submarine canyons are 

particularly suitable environments for the failure and 

displacement of sand-rich sediment by creep, slump, 

and various forms of gravity-induced mass flow including turbidity currents (Shepard and Dill, 1966). 

Such failure, in modern canyon heads, is largely attributed to the metastable physical properties of 

rapidly deposited sediment on relatively steep slopes 

(Moore, 1961; Dill, 1964). Abrupt loading associated 

with rapid deposition may be sufficient to initiate 

failure. Other commonly invoked triggering mechanisms of downslope failure are earthquakes (Chamberlain, 1964), movement of water masses (including 

storm, surge, tidal, and other current activity affecting 

the sea floor; cf. Keller and Shepard, 1978; Shepard 

and Marshall, 1978), and biogenic activity (Stanley, 

1971; Rowe, et al., 1974; Warme, et al., 1978). Once 

set in motion, it is believed that gravity-driven sediment flows displace material of mud to gravel size 

along the length of canyons to fans and other distal 

base-of-slope environments, and observations in 

modern ocean basins tend to bear this out (Shepard, 

et al., 1969; Heezen and Hollister, 1971; Nelson and 

Kulm, 1973; Walker, 1978). 

A second postulate to which attention also has been 

paid in recent "gres d'Annot" studies (Stanley, et al., 

1978) proposes that once sediment fails and is set in 

motion on a submarine slope, the initial mass gravity 

mechanisms involved in the displacement of material 

can evolve to another type during the course of transport. This flow evolution during a single transport 

event is termed "transformation." For instance, it has 

long been implied that slumps transform to turbidity 

currents in canyons (Kuenen, 1951; Morgenstern, 

1967). Recent investigations, based largely on theoretical considerations, but also on field observations, 

have outlined a rather more complex sequence of 

gravity-induced mechanisms that can occur between 

slumping and dilute turbidity current flow "endmembers" processes (Dott, 1963; Middleton and 

Hampton, 1973; Carter, 1975; Lowe, 1976; Middleton and Southard, 1977). 

This present study of "gres d'Annot" submarine 

canyon wall and canyon tributary deposits, an outgrowth of the previous investigations, is intended 

to identify the dominant most proximal sedimentation patterns. A survey of this type could provide 

further insight on the marked facies changes observed 

downslope in more distal settings. The examination 

of selected exposures should serve to (1) better define facies interpreted as canyon wall deposits, (2) 

document evidence of early-stage sediment failure in 

sequences believed to have moved along relatively 

steep slopes, and (3) identify the spectrum of mass 

gravity transport processes and their sequential evolution in the more proximal reaches of a continental 

margin. 

ACKNOWLEDGMENTS.—Drs. D. R. Lowe, Louisiana 

State University, and H. D. Palmer, Dames and 

Moore, Washington, kindly reviewed the manuscript. 

Travel and laboratory support funds for this study, 

part of the Mediterranean Basin (MEDIBA) Project, 

were provided by Smithsonian Research Grant 

71702120. 

General Setting and Background Information 

Briefly summarized here are the salient points that 

pertain to three outcrop localities where channelized 

sandstone tongues are exposed: Menton, on the Cote 

d'Azur Mediterranean coast, Contes, north of Nice, 

and the Braux region, east of Annot (Figure 1). The 

sand-rich units in the three regions were formerly 

termed, respectively, "gres de Menton", "gres de 

Contes" and "gres d'Annot". It is recognized that the 

base of these units is not strictly of the same age 

(ranges from Upper Eocene to Lower Oligocene, 

Campredon, 1972) and that they were deposited in 

different topographic depressions (Bouma, 1962). In 

a regional sense, however, the sandstone-rich units 

were deposited in the Nummulitic Sea, the final 

marine incursion in the region that occupied what 

is now the external sector of the southern Alpine 

Chain (Stanley, 1961), and are lithologically associated with, and genetically a part of, a regionally 

mappable series of marine sandstone and shale (with 

subordinate deposits of conglomerates) of approximately the same age. This entity is identified as a 

mappable formation that is now officially recorded 

as the "complex des gres d'Annot" (Bodelle, 1971; 

Campredon, 1972) and stratigraphically termed as 

such on the geological maps published by the French 

Bureau de Recherches Geologiques et Minieres. 

Herein, the unit is abbreviated "gres d'Annot" or 

Sandstone. 
NUMBER 4 

Sedimentological investigations of the Annot Sandstone have been reported upon elsewhere, and the 

reader interested in overviews of the different "gres 

d'Annot" facies, regional basin paleocurrent and 

paleogeographic analyses and transport processes is 

directed to two recent syntheses (Stanley, 1975; 

Stanley, et al., 1978). 

The exposures at the Menton, Contes, and Annot 

localities are comparable in the following respects: 

1. Sandstone-rich sections form the upper member 

of a marine Paleogene trinity consisting, from the 

base up, of Middle Eocene limestone, including some 

conglomerates (conglomerats a nummulites), Upper 

Eocene blue shales and marls (Marnes bleues), and 

a sequence of Upper Eocene and Lower Oligocene 

sandstone and shale strata ("gres d'Annot"). 

2. The Annot Sandstone units occur in asymetrically deformed synclines (generally the east limb of 

the syncline dips gently, about 30°, toward the west 

while the west limb dips steeply, and locally is vertical 

or overturned). 

3. The original thickness of the "gres d'Annot" 

has not been preserved at the three localities since 

the top of this youngest marine formation is an 

erosional surface. 

4. The most obvious sandstone exposures define 

linear SSE to NNW trending belts that consist largely 

of massive, moderately-well stratified, amalgamated 

pebbly-coarse sandstone strata identified as lower 

canyon to uppermost fan channel fills (Stanley, 1975; 

Stanley, et al., 1978). 

5. These linear sandstone belts, ranging from 200 

to over 300 m in thickness, are distributed in a direction that approximates the predominant paleocurrent 

directions (i.e., toward the north-northwest as simplified on the inset map in Figure 1). 

6. This porportion of distinct turbidites, thin 

laminated sandstone units, and finer-grained layers, 

including shale, in the massive sandstone sections is 

low. 

7. The contact between basal massive units of the 

thick shoestring sand bodies and the underlying 

Marnes bleues units is unconformable locally. 

8. North-trending fingers of thick, massive sandstone beds are bounded to the east or west (or both) 

by thinner and much better stratified sequences including enhanced proportions of sandstone and mudstone turbidites; these series are identified as lower 

slope intercanyon deposits (Stanley, 1975). 

9. Annot Sandstone exposures north of the Annot, 

Contes, and Menton localities are much thicker (350 m 

to over 650 m preserved thickness), cover substantially 

greater surface areas, and comprise laterally extensive 

turbidite sandstone and mudstone sheets that alternate 

with channelized sandstone deposits; these are recognized as fan deposits (Stanley and Unrug, 1972; 

Stanley, 1975; Stanley, et al., 1978). 

10. The paleocurrent indicators and mineralogical 

composition of these northern fan facies, as well as 

the exposures at Annot, Contes, and Menton, record 

a southern provenance and a principal north-trending 

dispersal pattern (Stanley, 1961; Bouma, 1962). 

11. The fan deposits accumulated in the Annot 

Basin where depths locally exceeded 1000 m; bathyal 

depths are estimated on the basis of margin slope gradients conservatively estimated at approximately 3° to 

5° (Stanley, 1961, 1975) and paleodepth evaluations 

of trace fossil assemblages (J. Wexler, unpublished 

data). 

12. Paleogeographic reconstructions show that 

sand-rich series in the Menton, Contes, and Annot 

areas were deposited on margins that dipped northward, away from a large subaerially exposed region 

that occupied part of the present Ligurian Sea south 

of the Mediterranean coast (Kuenen, 1959; Stanley, 

1961; Bouma, 1962; Bodelle, 1972). 

Much attention has been paid to the thick, massive, 

relatively coarse-grained sandstone facies that comprise the bulk of the canyon and upper fan valley fills; 

some of these units have been interpreted as "quick" 

beds from high-concentration underflows (Stanley, et 

al., 1978). In marked contrast, the regionally more 

extensive Annot Sandstone facies to the north include 

much higher proportions of graded sandstone and 

texturally finer fractions. This turbidite-rich, typically 

flysch, facies has been interpreted as deposition from 

flows that bypassed the canyon mouths and released 

their load on fan lobes and in basinal areas. 

Observations 

Mapping indicates that the most distinctive attributes common to the sand bodies at Annot, Contes, 

and Menton are confinement and limited lateral 

migration, linear to gently sinuous 'shoestring' configuration, and a more southerly geographic position 

relative to the "gres d'Annot" base-of-slope and fan 

to basin series immediately to the north (Stanley, 
SMITHSONIAN CONTRIBUTIONS TO THE MARINE SCIENCES 

1975). These sandstone bodies occupied important 

NNW-trending depressions, one to two kilometers 

wide, formed in the underlying Marnes bleues series. 

Determination of the primary topographic configuration of the top of the Marnes bleues strata on which 

the "gres d'Annot" accumulated is essential to the 

discussions that follow. The original axial downslope 

inclination of the NNW-trending channelized pods 

is difficult to ascertain. However, the uppermost 

Marnes bleues surface mapped in an east-west direction normal to the "shoestring" sand axes reveal 

minimal primary slopes between the margins and axes 

that exceed 10° in the Contes area and in the AnnotCoulomp-Braux sector (summarized in Stanley, 1961, 

fig. 4 and Stanley and Unrug, 1972, figs. 26 and 28). 

The contact between the top of the Marnes bleues 

and the base of the overlying "gres d'Annot" sand 

pods define a V-shaped, relatively high-relief profile 

that is comparable with some modern canyons and 

uppermost fan valleys (Shepard and Dill, 1966). 

These geometric observations, coupled with the detailed lithofacies information (summarized in Stanley, 

et al., 1978), has led me to interpret the massive 

bedded "gres d'Annot" units at the three localities 

as deposits that accumulated near canyon mouths, 

near the base of north-dipping slopes. 

The petrology and distribution patterns of the thick, 

usually amalgamated, sandstone bodies forming the 

canyon axis fill proper are detailed elsewhere (Stanley 

and Unrug, 1972; Stanley, 1975; Stanley, et al., 1978) 

and need not be described here. The facies bounding 

the valley axial fill, however, have not been sufficiently 

detailed, and attention herein is directed primarily to 

sandstone and shale deposits that draped the walls and 

filled lateral tributaries sculptured in the older Marnes 

bleues Formation. The arrows numbered 1 to 4 in 

Figure 1 show the location of the exposures illustrated 

in this study and their relation to the thick, linear 

SSE to NNW-trending canyon axes sandstone bodies. 

The field observations were made primarily: (a) near 

the village of Braux along road DUO that cuts the 

Crete de la Barre in the eastern part of the Annot 

syncline (arrow 1) ; along the lower parts of the cliffs 

formed by the massive sandstone west of the Coulomp 

River valley (arrow 2); (b) along road D115 near 

Sclos de Contes in the eastern part of the Contes 

syncline (arrow 3); and (c) along the series of the 

small roads (including D223 and D2566) that traverse 

the margins of the sandstone exposures in the Menton 

syncline (arrow 4). 

The quality of exposures is very good to excellent 

at localities (a) and (b), but only moderate in the 

Menton area (c) due to the combination of vegetation 

and high concentration of dwellings that cover large 

surfaces of the weathered outcrops. The sandstone is 

moderately cemented and variably friable at the three 

localities, and the interbedded finer-grained units 

are compacted to shale and siltstone grade. 

GENERAL ASPECTS AND GEOMETRY OF CANYON 

WALL FACIES 

Canyon wall sequences are for the most part less 

than 100 m thick in contrast to the thicker (to 300 m) 

sandstone canyon axis fill units (compare Figures 2 

and 3 with Figure 4); these are not true thicknesses, 

for in both cases the formation top is an erosional 

one. In contrast with the axial deposits, canyon wall 

facies include a much more diverse assemblage of 

stratal types and a significantly higher proportion 

of shale and fine-grained series interbedded with 

thick, massive sandstone units. Canyon wall facies 

comprising alternating sandstone and shale units, 

from a distance, appear flysch-like and resemble some 

base-of-slope fan and basinal deposits (Figure 2). 

On closer inspection, however, they are distinct from 

these more distal turbidite-rich sections as well as 

from adjacent intercanyon slope facies that consist of 

large proportions of thin, well-stratified, finer-grained 

laminated siltstone and sandstone units alternating 

with shales. The sand-shale ratio of some canyon wall 

sections approximates 1.0, in contrast to that of intercanyon lower slope facies (about or less than 0.5; 

illustrated by Stanley, 1975, fig. 37), and of axial 

fill deposits (locally >3 2 at the Annot locality, 

Figure 4). 

Even more obvious attributes of canyon wall facies 

are the highly irregular bed form, anomalous stratification attitude (Figure 4) and lateral discontinuity 

of the layers (Figure 2A). Marked thickness changes 

and wedging-out of bedding are commonly observed 

within a single exposure (Figure 2A, arrow b). Some 

beds can be traced for considerable distances, such 

as the 500m-long sandstone unit lying a few meters 

above the older Marnes bleues shales along road D115 

at the Sclos de Contes locality; where examined in 

detail, however, thick strata such as these almost 

always are non-uniform internally and frequently display moderately deformed to "chaotic" internal 

stratification features (Figures 5, 6). 
NUMBER 4 

Some lenticular sandstone units may be sharp-based 

(Figure 7A, B) and show no significant erosion of the 

underlying layer. Others may truncate parts of the 

underlying unit (Figure 8), or erode thicker series of 

beds including the Marnes bleues shales that formed 

the underlying canyon walls (Figures 2A, 4B). The 

most extensive canyon wall units observed are the 

deformed and anomalously dipping massive sandstone 

units forming the lower portion of the cliffs bounding 

the west bank of the Coulomp River valley. Some 

of the anomalous bedding are actually surface weathering phenomena. In other cases, however, the attitude 

of thick strata clearly is at marked variance with 

the general strike and dip of the massive sandstone 

beds that overlie them (Figure 4); here, stratification 

planes record directions that are normal or even 

reversed to the predominant SSE to NNW dip of the 

linear sandstone belt (see fig. 22 in Stanley, 1975). 

Maps of specific lithofacies reveal the marked discontinuity and lenticularity of strata along the length 

of the massive canyon fill shoestring bodies. This distinctive attribute of canyon wall deposits is illustrated 

by the patchy distribution of conglomerates, pebblerich sandstone strata, and chaotic slump units on the 

margins of the canyon axial fill in the Contes area 

(Stanley and Unrug, 1972, fig. 28). 

PREVAILING ASSEMBLAGE OF STRATA 

A predominant characteristic of canyon wall deposits is the highly varied succession of sandstone 

stratal types (Figure 3). Three stratification types in 

particular form a substantial proportion (>50% ) 

of the total thickness at some localities, such as the 

Crete de la Barre (Figures 3 and 7). None of these 

types is unique or specifically restricted to "gres 

d'Annot" canyon wall lithofacies; it is their relative 

importance and thickness that is characteristic. A brief 

description of each follows: 

TYPE 1.—Well-stratified, massive, generally amalgamated sandstone units (Figure 7A) are present 

but in lower proportions and often thinner than in 

the associated canyon axis and more distal fan channelupper fan sequences described by Stanley, et al. 

(1978). The strata consist of coarse sand or admixtures of coarse sand, granules, and small pebbles and 

range in thickness from 0.5 to about 10 m, but more 

commonly are 1 to 2 m thick. Some massive beds 

do not show any grading upward, while others are 

moderately well graded (coarse-tail grading), particularly at the base of the bed. In graded beds the a 

Bouma division comprises the bulk of the bed, or this 

horizon may be topped by a moderately to welldefined b laminated sandstone division (Figure 8B). 

These Ta and Ta_6 sequences often enclose isolated 

masses of deformed mudstone ("shale rip-up clasts") 

and sandstone blocks (Figure 9A, B) and armored 

mud balls (Figure 9C). These, and large cut-and-fill 

structures (Figures 8B) and discontinuous layers of 

shale (Figure 8A), record erosion by rapid succession of sand flows. Strata may be sharp-based (Figure 

7A, B) or display sole markings (Figure 10), including tool (some to 30 cm in width) and scour structures, some of which may be load deformed. Convolute lamination (Figure HA), and flame (Figure 

11A), dish (Figure 1 IB) and related water escape 

structures are sometimes observed. Disturbance of 

bedding by benthic organisms (bioturbation) is low 

to moderate: animal burrows sometimes extend across 

an entire bed as much as 2 m thick (examples at the 

Crete de la Barre section), and grazing and trail 

markings often cover entire bedding surfaces (Figure 

11C). 

TYPE 2.—This is a particularly diagnostic type of 

stratification and one of the more common in terms 

of total number of beds in canyon wall sequences; in 

contrast, it comprises only a minor proportion of the 

adjacent canyon axis lithofacies. It is identified by 

the moderately to extensively deformed horizons 

within, but not throughout, the bed (Figures 7B, 12). 

Commonly, the basal 20 to 60 cm of a sandstone 

layer (which in some cases is graded) is undeformed; 

this layer is covered by a disrupted horizon of sandstone (Figure 12A) or a mix of sandstone and 

shale (Figure 12B, C). The disrupted or deformed 

to chaotic part of the bed, variable in thickness 

(usually 20 to 150 cm thick), may be covered by 

undeformed, structureless (Figure 12C) or horizontally 

laminated sandstone. A variant of this type includes 

sandstone strata that display deformed stratification 

at the base of, and not within, the bed (Figure 12D). 

TYPE 3.—Strata of this type include sandstone, or 

shale, or sequences originally consisting of alternating 

sand and mud layers whose primary stratification has 

been completely disrupted (Figure 7C). These chaotic 

layers also occur in canyon axis-fan channel and baseof-slope environments, but in lower proportions. Several good examples of contorted layers (to 2 m thick) 
SMITHSONIAN CONTRIBUTIONS TO THE MARINE SCIENCES 

are exposed at the Crete de la Barre (Figure 13A); 

the exposure at Sclos de Contes reveals thick (to 

about 10 m) chaotic mudstone-sandstone layers within 

massive sandstone (Figures 5, 13B). These spatially 

and temporally discontinuous sequences (Figure 6) 

are commonly identified as slump deposits. Anomalously stratified beds, such as those west of the 

Coulomp River valley (Figure 4) are also grouped 

in this assemblage. 

OTHER TYPES.—Th e above three stratification types 

in the canyon wall sequences are complemented by 

variable, but generally low proportions, of thin (<5 0 

cm) turbidites (Ta.i„ T6.c, or Tt.e), interbedded shale 

and shale-thin turbidite alternations (Figure 14), 

moderately to poorly stratified muddy, gravelly sandstones and gravelly sandstones (Figures 15, 16C), 

occasional layers of discontinuous sandstone flow 

rolls, and thin, well-defined layers of plant and mica 

incorporated in either sandstone or shale strata 

(Figure 11D). Most of the above types are much more 

important in the more distal facies to the north. 

DISPERSAL PATTERNS 

Sediment transport directions have been mapped 

on the basis of the measured orientation of sole marking and cut-and-fill structures, pebble orientation, 

and slump axes. More often than not, measured 

paleocurrent directions in the "gres d'Annot" canyon 

wall facies are not consistent either with prevailing 

trends (to the north) mapped in the adjacent lower 

slope intercanyon series, or with the predominant 

current directions (SSE to NNW) of the major axial 

fill facies (Stanley, 1961; Stanley and Unrug, 1972; 

Stanley, 1975). Often scour or tool marks on a sandstone sole indicate several directions (Figure IOC), 

and this divergence may exceed 60°. 

Noteworthy are the marked differences in current 

directions recorded within a single locality. For instance, at the Crete de la Barre, the direction of sole 

markings changes upsection from S—>N and SE-»NW 

to E->W and NE->SW (Figure 3). Some SWtrending flute marks at this exposure record dispersal almost opposite to the predominant NW paleocurrent direction recorded in the thick sequence of 

axial fill sandstone west of the Coulomp River less 

than 1 km distant. Sole marking directions recorded 

at Sclos de Contes, Menton, and the Crete de la 

Barre, which appear "anomalous" to the regional 

trend, in fact indicate transport paths on slopes that 

are oblique or perpendicular to the major adjacent 

north-trending valley axes. Such paleocurrent measurements are actually consistent with a canyon wall 

and tributary canyon interpretation (Stanley, 1975) 

where terrigenous sediments likely would move on the 

steeper slopes and in tributary valleys oriented toward 

the canyon axis rather than down the more gently 

north-oriented continental margin. 

TEXTURE, FABRIC, AND MICROSTRUCTURE 

As might well be expected, the highly variable 

suite of stratal types interpreted as canyon wall deposits present a wide range of textures, fabric, and 

microstructures. A thin section and sieve analyses 

of over 110 samples collected at the three localities 

(this original unpublished data is available upon request from the author) sheds some light on the matter. 

Size frequency histograms for the friable, poorly 

cemented, massive sandstone samples show a bimodal 

distribution, i.e., a variable coarse modal class ranging from 0<f> to 3<f>, and a fine modal class in the 

finer than medium silt (<5<£ range). The textural 

analysis shows that primary matrix content (herein 

defined as material finer than 31/u.) ranges from about 

3 % to 30%, and is most commonly about 10% to 

15% in the thick massive sandstones (Figures 15A, 

B). Canyon wall sandstone thus includes both mature and immature textural types, and is not substantially different in this respect than canyon axis 

deposits. Some canyon wall sandstone units, however, 

reveal a lower fine-grained fraction than sandstone 

turbidites that, to the north, dominate typical Annot 

fan and basin sequences (Stanley, 1961, 1975; Bouma, 

1962). 

The matrix content, usually a brown calcareous, 

silty mud paste, tends to be much higher (>40% ) 

in some chaotically deformed beds. As expected, 

grain-to-grain contact and matrix content generally 

show an inverse relation: the greater the amount of 

matrix, the lower the grain-to-grain contact, and 

vice-versa. A semi-quantitative estimate of packing 

was made by counting the number of grain contacts 

of sand-sized framework particles in 80 large thin 

sections. This two-dimensional analysis shows a frequency of contact ranging from about 4 to 7 contacts per grain in some of the lower matrix (<10% ) 

sandstone. 
NUMBER 4 

The maximum diameter of granules and pebbles 

of metamorphic, igneous, and sedimentary (excluding 

reworked shale and sandstone fragments) origin 

usually ranges from 0.5 to 3.0 cm. Coarse fraction 

fabric studies in the field provide complimentary information on dispersal patterns. Pebbles may be 

concentrated at the base of sandstone beds and show 

grading (Figure 8B) or reverse grading (Figure 16B), 

or they may be irregularly dispersed in sandstone or 

muddy sandstone units. An attempt has been made 

to compare pebble orientation with sole mark directions in the same bed. Pebbles in some units are 

imbricated with the elongate axis dipping upslope 

(Figure 16A, B), but as a general observation clasts 

in most strata display a more random orientation 

and imbrication (Figure 16C). 

Large thin sections cut in sandy canyon wall deposits often show structures not visible on a weathered 

outcrop surface, such as vague or disrupted laminae, 

or the injection of finer textured siltstone in sandstone (Figure 15B). Laminae commonly consist of 

alternations of grain-thick layers of silt and sand, mica 

blades, and plant fragments. In some thin sections, 

laminae are deformed (Figure 15C) or discontinuous 

(pillars, convolutions, dish structures, Figure 11 A, 

B), and these water escape features record late transport or early post-depositional mechanisms (Lowe, 

1975). Bioturbation structures probably also modified 

the original fabric of some sandstone and siltstone 

layers. 

Interpretation of Dominant Stratal Types 

The assignment of specific transport mechanisms 

to "gres d'Annot" strata on the basis of observed 

stratification features should be approached with 

considerable caution. Several of the obvious sedimentary structures may be attributed to more than one 

emplacement mechanism. The depositional origin 

of other specific structures remains ambiguous. To 

complicate matters, it is likely that many of the 

sandstone types examined were emplaced by gradational, not pure "end-member" gravity flow mechanisms (Middleton and Hampton, 1973, 1976; Lowe, 

1976a, b). Moreover, structures and fabric tend to 

record terminal, or "freezing," depositional events 

(Walton, 1967; Carter, 1975) and post-depositional, 

including liquefaction, phenomena (Lowe, 1975) 

rather than active transport and immediately predepositional stages. In spite of these limitations, 

field description, coupled with laboratory petrologic 

examination, still provide the most useful data base 

with which to initiate a discussion of downslope transport processes in the environment under consideration. 

In so doing here, it is recognized that reasoning is 

largely by analogy, i.e., evaluating the final preserved 

product in light of theoretical and experimental investigations and by comparison, where possible, with 

analogs in modern subaqueous settings. 

The "gres d'Annot" sandstone strata described 

earlier all record some form of resedimentation involving failure and flow of sediment accompanied 

by a disruption of the original grain framework and 

formation of a new suite of primary structures upon 

deposition. Grain framework changes on the one 

hand induced failure, and also developed as a result 

of failure and downslope displacement. Attention is 

first directed to the type 3 stratification units that 

are particularly distinctive and which group "en 

masse" emplaced and chaotically stratified sediment 

sequences; these, widely recognized in both the modern and ancient sediment record, include slides and 

slumps. These are distinguished from the deposits 

of sediment gravity flows (flowage of sediment-fluid 

mixtures), and the presence of a gradient is needed 

for extensive displacement of both depositional types. 

Among the more striking examples of slides are thick, 

anomalously dipping strata that form the lower part 

of the Annot Sandstone cliff section west of the 

Coulomp River valley in the Annot area (Figure 4). 

It is herein suggested that large, partially consolidated sandy slabs moved along a well-defined set 

of slippage planes and were emplaced downslope 

"en masse" toward the base of the canyon margin. 

The mapped stratification attitude indicated preferential transport toward the west, that is, primarily 

toward the channel axis (dispersal depicted by Stanley, 1975, fig. 22B). Sliding on a somewhat more 

moderate scale is also denoted by the locally deformed 

base of the massive sandstone unit at the Sclos de 

Contes locality (Figure 12D). 

Slumping, involving displacement along multiple 

slippage planes, has resulted in movement of somewhat smaller masses of sediment. Shear during movement deformed most original structure and fabric, 

although some can generally still be recognized; the 

deposits suggest a churning motion that mixed unconsolidated mud and sand. Good examples of chaotic 
SMITHSONIAN CONTRIBUTIONS TO THE MARINE SCIENCES 

structure include the large shale and sandstone masses 

incorporated in the massive bedded unit at Sclos de 

Contes (Figures 5, 6, 13B), and several highly deformed layers of variable thickness at the Crete de 

la Barre section near Annot (Figure 13B). 

Somewhat less obvious in the "gres d'Annot" exposures than slides and slumps but more significant 

in terms of number are sandstone layers with pronounced deformation within the bed and/or at the 

bed boundaries. These, earlier described as type 2 

stratification units, are the product of several sediment flow processes, including liquefied flow on the 

basis of criteria described and illustrated by Lowe 

(1976b). A remarkable variety of such beds are exposed at the Crete de la Barre section (Figures 7B, 

12A-C). These display slight to extensive disruption 

of stratification, recording a collapse of metastable, 

loosely packed sand. Collapse, according to Lowe 

(1976b) and others, can occur just before failure 

by spontaneous liquefaction (cf. Terzaghi, 1956), 

or as a result of liquefaction following failure. Dilation and fabric breakdown under increased stress in 

some instances may have been induced along horizons 

of originally increased porosity and water content. 

Such horizons may have included laminations of mud, 

mica, and plant matter mixed with sand- and granulesize material as observed in field and thin-section 

observations (Figure 11D). Water squeezed out of 

loaded underlying sediment also may have triggered 

liquefaction in beds emplaced by sediment flow 

mechanisms other than liquefied flows. Experimental 

work suggests that as grains temporarily lose contact, 

flowage occurs on slopes of 10° or less for short 

distances before resedimentation. The process can 

begin by slump-creep (Carter, 1975) and retrogressive flow slides (Lowe, 1976b) and also can involve 

the "rafting" of sand above the failed zone. Probably 

internal deformation also records late-stage postdepositional liquefaction (Lowe, 1975). Similar 

modern deep marine analogs include the muddy 

organic-rich fills in some steep-walled canyon heads 

that fail by processes of creep and semi-continuous 

sand slumps as described by Dill (1964, 1967), 

Chamberlain (1964), and Marshall (1978). 

Stratification types 2 and 3 are probably most 

diagnostic of "gres d'Annot" canyon wall facies, but 

the exposures in the three study areas also include a 

large proportion of massive sandstone beds grouped 

as type 1 units. Descriptively these moderately to 

well-stratified beds can be readily distinguished from 

the more typical slide, slump, and internally deformed sandstone layers; in terms of emplacement, 

however, they are probably related to these processes. 

As a group, type 1 units display structures attributed 

to a spectrum of sediment-fluid flow processes that, 

depending on the author, would include grain flows 

(Stauffer, 1967), fluidized (Middleton and Hampton, 

1973) and liquefied (Lowe, 1976b) flows, slurry flows 

(Carter, 1975), and "quick" beds from high-concentration underflows (Middleton, 1967; Stanley, et al., 

1978) and, in the case of muddy, pebbly sandstones, 

to debris flows (Hampton, 1972). Some studies, for 

instance, have suggested that fluidized flows (sediment 

is supported by the upward flow of fluid escaping 

between grains) and grain flows (sediment is supported by grain-to-grain interactions, cf. dispersive 

pressure of Bagnold, 1956) could not account for 

the formation of the thick sandstone units encounterd 

in ancient deep marine sequences (Lowe, 1976a, b). 

At this time there remain fundamental disagreements 

as to the physics of particle-fluid motion, natural 

conditions required, and specific structures of resedimented, thick, non-graded sandstone layers. A classification of sediment gravity flows that emphasizes 

grain support mechanisms (by fluidization, grain-tograin interaction, fluid turbulence, and matrix 

strength) presented by Middleton and Hampton 

(1973) is appealing because it takes into account 

a possible gradation between such grain support 

mechanisms during flow. In most cases, however, it 

would be premature to attribute sedimentary structures of a "gres d'Annot" type 1 coarse, massive 

bedded sandstone to a specific grain support mechanism. Fabric, an attribute most affected by final 

stage and post-depositional events, is of questionable 

value in making such an assessment. Matrix content, 

however, may be a more reliable indicator of process. 

Thin-section and sieve analyses show that matrix 

content in type 1 units ranges from less than 5 % 

to over 30% (Figure 15A), and this silt and clay 

material, once part of the interstitial fluid, aided 

in suspension of the larger grains during flow (Hampton, 1972). 

For field work purposes, a very simplified genetic 

subdivision of type 1 sandstone beds involves two 

very generalized process "end-members": (a) flowage of sediment-fluid mixtures involving matrix 

strength where larger grains have been supported by 
NUMBER 4 

a mixture of fluid and fine sediment; such deposits, 

attributed to debris flow, usually display coarse grains 

"floating" among finer grains, but no graded bedding, 

and generally contain a substantial matrix content 

(Figure 16) ; and (b) water saturated flow involving 

lower matrix strength, somewhat lower clast concentrations and gradational spectrum of grain support mechanisms (grouping liquified, fluidized, grain, 

slurry, and dense turbidity current flows of the various 

authors cited earlier), and non-specifically termed 

"sand flow" (Stanley, 1975). The latter is applied 

until more precise criteria are developed for interpreting thick sandstone deposits with or without sole 

markings that display no or poorly developed graded 

bedding (Figure 7A) or, occasionally, reversed graded 

bedding and water escape structures. Indication of 

the turbulent nature of the base of such flows is 

recorded by the multiple sole marking orientation 

(Figure IOC) ; rapid deposition of the highly charged 

mass resulted in final stage and post-depositional rearrangement of sediment grains by escaping water 

(see structures in Figures 11 A, B and 15 A, C). Some 

Type 1 massive sandstone sand flow deposits that display poorly to moderately developed graded bedding 

(Figure 14B) and an incomplete sequence of Bouma 

(1962) divisions were probably emplaced by a continuum of high density flows that involve turbulence 

and dispersive pressure as grain support mechanisms. 

These strata are identified as Ta and Ta_6 turbidites 

(Figure 14A) deposited from high-concentration 

underflows (cf. Middleton, 1967) or from flows 

transitional between liquefied and turbidity currents 

(Lowe, 1976b). 

In addition to stratal types 1, 2, and 3, there are 

sandstone units that account for a lower proportion of 

the total "gres d'Annot" canyon wall lithofacies, but 

whose origins are somewhat better understood. These 

include thinner "classic" graded Ttt_c, T6.c, and T&.,, 

turbidites (Figure 14C) at each of three canyon 

localities. Turbidity currents also were responsible 

for the emplacement of a significant proportion of 

thin laminated silt and shale layers at the Crete de 

la Barre (Figure 14C). Thin-section, grain size, and 

compositional studies indicate that muddy turbidity 

flows (criteria based on those defined by Rupke and 

Stanley, 1974, and Piper, 1978) were more important 

than hemipelagic suspension processes in the deposition of interbedded shales in the study areas. 

Lateral Infill: Inferences and Discussion 

The highly varied assemblages of Annot Sandstone stratal types, their aerially restricted distribution 

along margins of channelized sand bodies, and the 

interpreted transport processes collectively define a 

distinctive resedimentation pattern. The geometric, 

petrologic, and paleocurrent attributes at the Menton, 

Contes, and Annot localities record the deposition of 

coarse-grained terrigenous materials in restricted slope 

environments where transport trends are oriented 

largely toward channelized "shoestring" sandstone 

bodies. Together, observations and speculations help 

elucidate lateral infill phenomena on lower canyon 

flanks, probably at a position close to the mouth of 

canyons. 

The original thickness of the Annot Sandstone is 

not preserved (the top of the Formation is an erosional surface), but overall it apears that deposits 

interpreted as canyon wall and tributary sequences are 

thinner and considerably more irregular in geometry 

and temporal-spatial distribution that the associated 

canyon axes facies. Most individual layers cannot be 

correlated over distances in excess of one kilometer. 

Also obvious are the unconformities between the 

Annot Sandstone and underlying Marnes bleues 

shales, and within the Annot Sandstone, suggesting 

that the canyon margins were unevenly covered by 

sand, muddy sand, pebbly sand, pebbly mud, and 

silty mud. Although individual layers are spatially 

restricted, the considerable thickness of many "gres 

d'Annot" beds (commonly ranges from 0.5 to 4.0 

meters) indicates displacement of large volumes of 

material by single sediment transport events. This 

becomes apparent if one considers that a lenticular 

1-meter-thick sand unit deposited over a 1 km2 

surface involves downslope transport of at least one 

million cubic meters of sediment. Periodic failure of 

packets of sand and mud would have exposed, at 

least locally, the Marnes bleues shales that formed 

the underlying canyon margin surfaces (schematic 

profile in Figure 17). 

The diverse successions of slides, slumps, and 

products of debris flow and various sand flow mechanisms characterize dynamic reworking (recurring 

failure—»erosion—» transport) rather than a progradational regime (transport—^deposition—^permanent 

emplacement). It is expected that a regime of this 

type, where erosion and mass wasting of the canyon 

margins prevailed, would have contributed some of 
10 SMITHSONIAN CONTRIBUTIONS TO THE MARINE SCIENCES 

the material that could be moved downslope. Sliding and slumping were particularly important in 

fostering this intrabasinal provenance-and-dispersal 

phenomenon. The slower sawing and grinding action 

of sand against stiff, partially lithified series forming 

the margins also may have been an effective process; 

undercutting by moving sand leads to failure as has 

been shown in modern canyon heads (Dill, 1964). 

Some indication of erosion by sand is recorded in 

"gres d'Annot" exposures by cut-and-fill (Figure 8B) 

and small channel structures (Figure 16C), and by 

the partial to complete removal of mud and thin 

sand layers between and within the thicker, massive 

sand layers (Figure 8A). The burrowing action of 

organisms also contributed to the weakening of partially consolidated "gres d'Annot" and Marnes bleues 

series forming the canyon wall and tributary surfaces (Stanley, 1971). Failed undercut and bioturbated sections provided mud and sand fragments 

of varying size and shape commonly observed as 

shale and sandstone clasts in the thick, massivebedded sandstone units. These olistoliths, some quite 

large (> 1 m), were initially "rafted" on the slowly 

moving mass of sand, while others subsequently were 

remobilized and incorporated in the sandy units 

emplaced further downslope by debris and highdensity flows, including turbidity currents. Armored 

mud balls (Figure 9C) show that the eroded blocks 

of mud were subjected to rounding and became 

coated with sand and granules during the short downmargin transit toward the axis. 

From the study of canyon heads off Southern 

California (Chamberlain, 1964; Shepard and Dill, 

1966) and in the Mediterranean (Groupe Estocade, 

1977) and theoretical and experimental investigations 

of resedimented deposits it is surmised that failure 

and initiation of flow in the Annot Sandstone environment under discussion can be triggered by 

diverse mechanisms. These, summarized from Lowe 

(1976b), include: earthquakes; abrupt loading associated with rapid deposition; development of excess 

pore-fluid pressures through movement of artesian 

water; failure of sediment accumulated to a slope 

near its internal friction angle; failure by loss of 

support by sediment undercutting sediment sections; 

failure along planes of weaknesses (underconsolidated 

mud laminae; bioturbated horizons (Stanley, 1971) ; 

plant, mica, and organic-rich layers, etc.,). Recent 

work shows that the vibratory action of water masses 

concentrated in canyons, as discussed by Shepard and 

Marshall (1978), also is a potential trigger mechanism. The specific cause of slides, slumps, and 

gravity sediment flows in the Annot Basin remains 

undefined, but a combination of several factors is 

suspected: the entire formation accumulated in two 

million years or less (Stanley, 1961) implying a rapid 

build-up of sediment and loading on the outermost 

shelf, uppermost slope and canyon margins; and 

earthquake tremors also would have been likely in 

this rapidly evolving structural setting at the end 

of the Eocene and early Oligocene. Rapid deposition 

of sand on tectonically mobile subaqueous slopes would 

provide conditions suitable for the inducement of 

sudden changes in physical properties (framework 

grain support, porosity, reduction of internal resistance to shear) ; it would, in fact, be difficult to 

envision permanent accumulation of the prograding 

sand-rich masses under such conditions. 

The "gres d'Annot" canyon margin processes are 

identified with different degrees of confidence. The 

deposits emplaced by slumping, debris flows, and 

turbidity currents are more readily recognized. As 

was earlier emphasized, however, most sandstone 

layers were transported by less obvious gradational 

flow mechanisms involving debris flow, liquefied 

flow, and high-concentration flows, including turbidity 

currents. It is likely that the quick massive stratal 

types were released from mass flow transport events 

that evolved during their progression downslope, and 

a lateral infill scheme is envisioned whereby slumps 

and retrogressive flow slides transformed to debris and 

sand flows and even dilute turbidity currents within 

the small distance and short transit time involved. 

The lithofacies succession indicates a distinctive 

repetitive pattern of erosion—^transport—^deposition. 

Some hypothetical examples are depicted in Figure 

17: diagrams A to C illustrate simpler modes, and 

D to F show more complicated possibilities. In A 

the sediment mass is displaced by creep and creepslump processes and then further modified by liquefaction; this is recorded by some type 2 stratification 

units (Figure 12). B depicts transport evolving to 

slumps or slides, resulting in type 3 units (Figure 13). 

In C creep, slump-creep, and retrogressive flow slides 

give rise to fluid-sediment flows involving debris and 

a variety of high-concentration sand flows, including 

turbidity currents; the deposits as a group are identified in the field as type 1 units. Modes D, E, and F 
NUMBER 4 11 

show somewhat more complex failure—^transport—> 

deposition patterns. It is this variable succession of 

transformation events that is the most distinctive 

aspect of Annot Sandstone canyon margin sedimentation. 

The lateral infill regime outlined above affected 

sedimentation in adjoining parts of the Annot Basin 

margins. For example, movement of substantial volumes of material from the canyon walls to the axis 

probably triggered movement upslope in the canyon 

as well as downslope in the canyon axes by a "chainreaction" effect as has been proposed for some 

modern canyons (Stanley, 1974). Also worth noting 

is the presence at Menton, Contes, and Annot of 

thick Ta and T0_i, sandstone layers of probable 

turbidite origin and minor proportions of more complete turbidites in both the canyon margin and 

canyon fill facies: turbidity currents initiated upcanyon released an important part of their coarse 

fraction load in geographically proximal sectors prior 

to and upon reaching the canyon axis. This would 

substantiate the contention that transformations from 

slumping, liquefied flows, and other sediment gravity 

flows to turbidity currents (where grain support is 

primarily by fluid turbulence mechanisms) occurred 

primarily on the steeper slopes of the canyons and 

uppermost fan sectors seaward of canyon mouths as 

suggested in an earlier study (Stanley, et al., 1978). 

As presently envisioned, coarse materials from 

turbidity current related high-concentration underflows were trapped on the margins and in the axes 

of lower canyons and fan channels, while thinner 

sheets of better developed graded sandstone and 

finer fractions forming large fan lobes in the Annot 

Basin were released progressively from the more 

dilute parts of these turbidity currents. 

Detailed analyses of sediment gravity flows and 

their deposits in different modern canyon settings 

are needed to amplify knowledge on lateral infill 

patterns and to further test some of the ideas proposed in the present investigation. 
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of Petroleum Geologists, 62:932-966. 

Walton, E. K. 

1967. The Sequence of Internal Structures in Turbidites. 

Scottish Journal of Geology, 3:306-317. 

Warme, J. E., R. A. Slater, and R. A. Cooper 

1978. Bioerosion in Submarine Canyons. In D. J. Stanley 

and G. Kelling, editors, Sedimentation in Sub-
14 SMITHSONIAN CONTRIBUTIONS TO THE MARINE SCIENCES 

marine Canyons, Fans, and Trenches, pages 65-70. Herefordshire. Quarterly Journal of the Geological 

Stroudsburg, Pennsylvania: Dowden, Hutchinson & Society of London, 118:319-347. 

Ross. 1976. Submarine Canyons and Deep-Sea Fans, Modern 

Whitaker, J.H.Mc. and Ancient. 460 pages. Stroudsburg, Pennsyl1962. The Geology of the Area around Leintwardine, vania: Dowden, Hutchinson & Ross. 
Figures 

MEDITERRANEAN 

FIGURE 1.—Maps showing location of Annot Sandstone in three synclines in French Maritime 

Alps; formation overlies Eocene shale (Marnes bleues) and limestone (calcaire nummulitique) 

series. (Arrows = position of canyon margin exposures discussed in text: 1, Crete de la Barre 

section; 2, base of cliffs west of Coulomp River valley; 3, Sclos de Contes section; and 4, 

exposures along road D-223 northwest of Menton.) 

15 
FIGURE 2.-Photographs oriented toward northwest showing Crete de la Barre section in 

Annot syncline (Figure 1, arrow 1). (Arrow a = stratal thickness changes along outcrop; 

arrow b = pinch-out and unconformable contact of "grb d'Annot" section with underlying 

Marries bleues shales that formed lower canyon margin.) 
NUMBER 4 17 

GRAPHIC 

LOG 

STRATA 

TYPE 

PALEOCURRENT 

DIRECTION 

GRAPHIC 

LOG 

STRATA 

TYPE 

PALEOCURRENT 

DIRECTION 

14 

13 

32-^ t •£*a 

10 

®*-

MARNES 

BLEUES 

ESE, flutes 

WNW-ESE, groove, 

slide morlcs 

NW-SE, grooves 

NW-SE, grooves 

NW-SE, grooves 

WSW, W, flutes 

-FIG . I2C 

I N-S. NW-SE, grooves 

FIG. I2B 

FIG. IOC 

I E-W, NE-SW, grooves 

SW, flutes 

FIG. I3A 

N-S, E-W, grooves 

FIG. I2A 

N-S, NW-SE, grooves 

_FIG. MB 

Nt-sW , grooves 

-FIG . I5C 

| NW-SE, grooves 

-FIG . 7C 

N-S, axis of 

deformed strata 

N-S, porting lineation 

-FIG . I0A,B 

NE-SW, grooves 

J5 

pea 

JO 

wmm 

.W f^ilAi^ t 

NNE-SSW, grooves 

NE-SW, grooves 

N-S, grooves 

NE, pebbles 

NE-SW, grooves 

NE, flutes 

NE-SW, grooves 

NE-SW, grooves 

-•'.:••.'*•.«,••- . 

to 

~^MM& 

-FIGS. 7A, I5B 

NE, grooves 

WNW-ESE, grooves 

-FIG . 7B 

wswm 

WNW-ESE, E-W, grooves 

E-W, oriented loads 

N-S, NE-SW, grooves 

N-S, NE-SW, grooves 

ESE, flutes 

STRATA TYPE: I Type I unit Sh - Shale-rich sequence 

2 Type 2 unit FF = Fine flysch sequence 

3 Type 3 unit T = 'Classic' turbidite 

T-S • Turbidite-shale sequence 

FIGURE 3.—Simplified graphic log depicting facies at Crete de la Barre section near Braux 

interpreted as tributary canyon deposit (modified from Stanley, 1975). (Note lithologic, paleocurrent, and stratification diversity; different strata types are described in text and photographs 

of specific examples, denoted by arrows, are illustrated in Figures 7 to 16.) 
18 SMITH SONIAN CONTRIBUTIONS TO THE MARINE SCIENCES 

FIGURE 4.-Annot Sandstone exposures west of Coulomp River valley (Figure 1, arrow 2), 

showing anomalously dipping stratification of slide deposits that form lower part of section 

; base of "grks d'Annot" section at a truncates underlying Marnes bleues shales. 
NUMBER 4 

Gr'es de Contes 

Telephone pole 

500m 

le Serre 

FIGURE 5.-Detailed map of Annot Sandstone at Sclos de Contes (road D-115) locality in 

the Contes syncline (Figure 1, arrow 3). The 500 meter-long road-cut section is illustrated 

in Figure 6; photo inset illustrates a slump unit of contored sandstone and shale within the 

massive sandstone (bar = 150 cm) . 
20 SMITHSONIAN CONTRIBUTIONS TO THE MARINE SCIENCES 

200 320 

FIGURE 6.—Graphic depiction of Annot Sandstone exposure at Sclos de Contes locality 

(Figure 5). (Horizontal and vertical scales in meters; X2 vertical exaggeration.) 
NUMBER 4 21 

TELEPHONE POLE $&£• £ MASSIVE SANDSTONE 

THIN SILTSTONE AND 

SHALE STRATA SANDSTONE TURBIDITES 

3W3 MUD-RICH CONTORTED 

SLUMP ZONE 

3P ALTERNATING THIN SANDSTONE 

AND SHALE STRATA 

" I — 

160 

" I — 

180 

- 1 

iO 140 150 170 190 200 210 

D 340

 h 350 430 J 440 450 460 
FIGURE 7.-Examples of diagnostic canyon margin stratification types (examples selected from 

Cr2te de la Barre section) : A, type 1 unit (Figure 2, sequence 22) ; B, type 2 unit (Figure 2, 

sequence 2 1 ) ; C, type 3 unit (Figure 2, sequence 3) ; (hammer = 2 cm) . 
NUMBER 4 23 

FIGURE 8.4tructures displayed by type 1 massive sandstone units at Menton locality (Figure 

1, arrow 4) ; A, discontinuous and truncated shale horizons; B, cut-and-fill base of a graded 

pebbly sandstone cuts underlying thin shale and sandstone. (Book length = 20 cm.) 
24 SMITHSONIAN CONTRIBUTIONS TO THE MARINE SCIENCES 

FI~URE 9.-A, shale "rip-up" clasts (Menton) ; B, sandstone olistolith (Contes) ; C, armored 

mudball (Contes) in type 1 sandstone units. (Ruler scale = 15 cm; hammer = 28 cm.) 
NUMBER 4 

FIGURE 10.Groove marks on soles of sandstone beds at Crete de la Barre section: A and B, 

Figure 2, sequence 35; C, diverging marks of sole, Figure 2, sequence 7. (Hammer = 28 m.) 
FIGURE 11.-A, Flame structures (a) and convolute lamination (b) at Sclos de Contes locality 

(Figure 6, near point 430 m) ; B, dish structures in type 1 massive sandstone bed, near Braux 

(bar scale = 50 cm) ; C, bioturbated sandstone surface at Crete de la Barre section (pencil 

= 15 cm); D, laminations of plant matter and mica (dark layers) in sandstone at Sclos de 

Contes locality (Figure 6, near point 420 m). 
NUMBER 4 27 

FIGURE 12.-Examples of type 2 stratification: A and B, deformed layers above thin, distinctly stratified sandstone at Crete de la Barre section (Figure 2, sequences 5 and 8) ; C, 

deformed layer forming the part of stratum (Figure 2, above sequence 8) ; D, deformed 

base of thick unit mapped at Sclos de Contes (Figure 6, near point 370 m) ; hammer = 28 

cm; book = 20 cm. 
28 SMITHSONIAN CONTRIBUTIONS TO THE MARINE SCIENCES 

FIGURE 13.-Examples of type 3 stratification: A, original bedding completely deformed in 

layer at Crete de la Barre section (Figure 2, sequence 6) ; B, chaotic units in massive sandstone at Sclos de Contes section in 18-m-thick section, near telephone poles b and c, Figure 6. 
NUMBER 4 29 

FIGURE 14.--Graded turbidite sequences associated with canyon margin facies: A, Tr3 at 

Menton locality (Figure 1, arrow 4) ; By upper units is a Tc. sequence and lower unit is a 

Ta-B bed (Figure 2, exposure between sequences 3 and 4) ; C, T,-a sequence at Crete de la 

Barre section (Figure 2, below sequence 2). (Ruler scale = 15 em; hammer = 28 cm.) 
SMITHSONIAN CONTRIBUTIONS TO THE MARINE SCIEI 

FIGURE 15.-Photomicrographs of selected Annot Sandstone samples: A, coarse, poorly sorted 

sandstone showing large grains (>2 mm) supported by coarse to medium-grained sand 

framework grains and a silty mud matrix, from Menton locality (Figure 1, arrow 4) ; B, thin 

flame of fine-grained sandstone and siltstone (arrows) injected into medium- to coarse-grained 

sandstone at Crate de la Barre (Figure 2, sequence 22) ; C, flowage (dish or water escape) 

structure in fine-grained sandstone-siltstone section at Crete de la Barre (Figure 2, sequence 3). 
FIGURE 16.-A, Shale clast imbrication in massive type 1 sandstone unit (Menton locality); 

B, pebble imbrication and reversed graded bedding in type 1 unit (Contes locality); C, small 

gravely sandstone-filled channel (random pebble orientation) truncating sandstone (Menton 

locality). (Ruler scale = 15 cm.) 
32 SMITHSONIAN CONTRIBUTIONS TO THE MARINE SCIENCES 

FIGURE 17.—Schematic summarization of canyon margin sedimentation and lateral infill based 

on study of three Annot Sandstone localities, emphasizing the diagnostic erosion-> transport-* 

deposition pattern and variability of successive transformation modes.