Sedimentary geology at Williams College

Rónadh Cox, Brust Professor of Geology and Mineralogy

Lavaka-Gallery

: Young lavaka with vertically-dropped

: Young Eucalyptus growing on walls of active lavaka

: Young active lavaka with grottoes in headwall

: Young active lavaka downslope from mature tree stand. No enhanced erosion associated with cattle tracks to right.

: Young active and old inactive lavaka in convex hillslope with rice terraces in foreground

: Within a grotto: vertical cracks

: Within a grotto: vertical cracks

: Within a grotto: vertical cracks

: Within a grotto: vertical cracks

: Weathered/eroded roadcut and old

: Weathering of sidewall

: Weathered vegetated lavaka has cut back to ridge crest.

: Weathered and eroded septae in stage III lavaka

: Weathered and eroded septae in stage III lavaka

: View toward outfall of early stage V lavaka

: View to headwall from vegetated base of barely active lavaka lobe

: View into widened outfall of large stage III lavaka complex

: View from valley into lavaka

: View into cultivated outfall valley from sidewall of stage III lavaka

: View into active stage III lavaka: recent wallfalls form debris apron against headwall in distance

: View from vegetated outfall of recently reactivated lavaka

: View from vegetated outfall of eroded septum and vertical headwall

: View from top of stage V lavaka toward younger lavaka developed in flank

: View from outfall of v-shaped inactive lavaka

: View from outfall of stage V lavaka with newer lavaka developed on right wall

: View from outfall of barely active stage III lavaka

: View from outfall of barely active lavaka

: View from outfall into stage III multi-septate lavaka

: View from outfall into stage III lavaka

: View from headwall of small

: View from headwall of reactivated lavaka showing fresh debris aprons above vegetated lower lavaka and outfall. Across the…

: View from outfall area into stage III multi-septate lavaka

: View from headwall to mouth of lavaka at head of outfall channel (not visible downslope)

: View from headwall onto recently fallen surface. Vegetated surface is horizontal: no rotational component to fall

: View from headwall of partially vegetated outfall with recent sand deposits

: View from headwall of one active large lavaka to active lavaka and bare eroded ground on opposite hillslope. Manioc field in…

: View from headwall of C75 showing large lavaka in mid-ground cutting back through plateau

: View from headwall of active lavaka

: View from headwall of active lavaka

: View from headwall of (unseen) lavaka

: View from head of sporadically active lavaka

: View from cultivated outfall area up into sporadically active stage III lavaka

: View down narrow lavaka

: view across valley from headwall of one lavaka to set of inactive lavakas on far side

: Very long

: Vertical walls

: Vertical walls with cracks and undercutting

: Vertical walls and grottoes in saprolite

: Vertical wall

: Vertical wall

: Vertical wall in saprolite

: Vertical upper walls and debris aprons covering lower walls in active lavaka

: Vertical sidewall

: Vertical sidewall and flat floor in young lavaka

: Vertical upper lavaka wall. Dark colour is wetted laterite; paler material below is dry

: Vertical saprolite walls

: Vertical piping in headwall

: Vertical piping

: Vertical pipes

: Vertical pipes

: Vertical pipes and grottoes in clay-painted wall of largely inactive lavaka

: Vertical pipes and grottoes

: Vertical headwall of active lavaka. Dark patches on saprolite represent seeping groundwater

: Vertical cracks in lavaka sidewall. Planar crack morphology unusual: pipes are more common

: Vertical clay-painted headwall with recent undercutting fall at base.

: Vegetated

: Vegetated outfall of sporadically active lavaka

: Vegetated narrow outfall in foreground

: Vegetated lavaka

: Vegetated interior of mature stage III lavaka

: Vegetated debris apron at lavaka outfall

: Vegetated and weathered lavaka. Eucalyptus are coppiced

: Valley lined with convex hillslopes. Lavakas on left side

: Unvegetated

: Unusual lavaka and gully morphology

: Unusual hook-shaped lavaka

: Undercut saprolite exposed in lavaka sidewall

: Undercut Eucalyptus sapling hanging from headwall

: Two small newer lavakas on wall of old stage V lavaka

: Two small active lavakas and one inactive

: Two lobes. Old lavakas

: Two lobes. Old lavakas

: Two adjacent lavakas

: Two adjacent lavakas coalesced by erosion of the separating hillslope. Smaller lavaka to lower left has long vertical pipe…

: Two active lavakas

: Two active lavakas with dark-stained saprolite indicating groundwater seepage. No recent sand evident in valley

: Two active lavakas separated by an eroding walls

: Two active lavakas separated by an eroding wall

: Two active lavakas below bare ground patch

: Trees colonising active lavaka

: Tree-filled lavaka with bare vertical walls still shedding some sediment

: Toeslope lavakas at edge or rizière

: Toeslope lavakas at edge of rizière

: Systematic plantings (appearing as a stippled pattern on the bare sand deposits of last season) are an attempt to stabilise…

: Steep headwall in mature lavaka

: Steep exposures of laterite and saprolite

: Three conjoined lavakas

: Stage III lavakas

: Stage III lavakas

: Stage III lavaka

: Stage III lavaka

: Stage III lavaka with debris-apron mantled lower walls

: Stage III lavaka retains substantial vertical face in headwall but has little recent sediment in lavaka bottom

: Stage III lavaka has lower sidewalls hidden by vegetated debris aprons

: Stacked sand beds indicate multiple recent sedimentation events from nearby lavaka. Sand beds are variously massive

: Sporadically active lavaka

: Sporadically active lavaka

: Stage III and IV lavakas

: Sporadically active late stage III

: Sporadically active but largely infilled lavaka

: Some remaining vertical head and side wall surfaces in stage III lavaka

: Small-scale lavaka-like erosion in walls of stage V ancient lavaka

: Small-scale lavaka-like erosion in walls of stage V ancient lavaka

: Small-scale activity in sidewall of stage III lavaka

: Small lavaka

: Small lavaka

: Small

: Small two-lobed lavaka

: Small lavaka

: Small inactive lavaka

: Small field on grassy surface in stage III lavaka

: Small active lavaka. Recent sand deposits at lavaka mouth have been planted with bananas

: Small active lavaka with grottoes in back wall and hook-shaped outfall

: Small active lavaka flanked by ancient

: Skyline view of eroding wall between two lavakas

: Sisal plantings on lower slope suggest recent activity from bare walls above path

: Skyline view of eroding wall between two lavakas

: Sisal plantings in base of small wall-falls in stage III lavaka

: Side-septae in partially vegetated lavaka

: Side view of lavaka shows convex hillslope profile

: Showing headwall of lavaka cut back through ridge to next drainage

: Shedding (light) and clay-painted walls in stage III lavaka

: Several erosional forms in hillslope: active lavaka

: Sediment moved along wide flat lavaka floor feeds into narrow incised outfall

: Sediment gravity flow of recent wallfall material over-rides vegetation in recently reactivated lavaka

: Saprolite of varying composition

: Sediment being shed from top of sidewall; lower bare sidewall is clay painted

: Saprolite preserves primary geological structures: pegmatite cross-cutting gneissic foliation

: Saprolite exposures in vertical wall (top and left)

: Roots exposed in sidewall overhang

: Roof fall (vegetated

: Rolling convex slopes in low-lying plain

: Rolling convex slopes in low-lying plain

: Rolling convex slopes in low-lying plain

: Rolling convex slopes in low-lying plain

: Road cut along sidewall of old

: Road along sidewall of mature

: Right side of lavaka shows recent activity; left side is heavily clay-painted and partially vegetated

: Ricefields within stage IV lavaka

: Ricefields in outfall of inactive lavaka

: Rice fields in outfall of stage III lavaka

: Rice and vegetable fields in outfall area of large

: Red laterite above tan and white saprolite in vertical headwall of lightly active stage III lavaka

: Red laterite above pale saprolite in lavaka wall

: Recently reactivated lavaka preserves older

: Recently reactivated lavaka headwall

: Recently reactivated lavaka headwall on right

: Recently reactivated lavaka

: Recent wallfall

: Recent wallfall exposes fresh saprolite and also deposits of older

: Recent wall fall in stage III lavaka

: Recent wall fall forms overhang in active lavaka

: Recent vertical falls indicated by vegetated surfaces within blockfall pile at base of lavaka

: Recent vertical fall from headwall (retaining surface vegetation on upper horizontal surface)

: Recent vertical drop of headwall material (upper flat vegetated surface still preserved)

: Recent small-scale reactivation in headwall of stage III lavaka; note sisal plantings at base (stabilisation attempt)

: Recent sediment movement in sporadically active

: Recent sediment movement and debris apron construction

: Recent substantial wallfall in sporadically active lavaka (walls unvegetated but substantially clay-painted)

: Recent sediment movement (with sediment gravity flow morphology) in active lavaka wall

: Recent sand flow from lavaka just visible in valley

: Recent sand deposits in bottom of reactivated lavaka

: Recent sand deposits from active lavaka carpet the valley bottom

: Recent reactivation of old

: Recent reactivation (stage II-III) of old (stage V) lavaka

: Recent reactivation (stage II) of old lavaka. Sisal plantings in base (attempted stabilisation)

: Recent reactivation (stage II-III) of old (stage V) lavaka

: Recent reactivation (stage II) of old lavaka. Sisal plantings in base (attempted stabilisation)

: Recent reactivation (stage II) of old lavaka. Sisal plantings in base (attempted stabilisation)

: Recent reactivation (pale saprolite exposures) of heavily clay-painted (dark upper walls) stage III lavaka

: Recent fluidised flow and debris flow deposits form debris apron on active lavaka headwall

: Recent fall of lateritic debris (red) mantling outcrops of saprolite (pale)

: Recent blockflow in outfall

: Recent blockfalls in saprolite

: Recent blockfall in small lavaka

: Recent blockfall and grottoes in active lavaka sidewall

: Recent block and sand fall (mostly tan-coloured laterite) contributes to debris apron at base of wall

: Recent activity in stage II lavaka

: Recent activity in stage II lavaka

: Recent activity in stage II lavaka

: Recent activity in reactivated lavaka: mixed blockfall and fluidised flow

: Recent activity in reactivated lavaka

: Recent activity in reactivated lavaka

: Recent activity in lavaka interior

: Reactivation on left side of vegetated

: Reactivation of left side of formerly inactive

: Reactivated lavaka with one remaining clay-painted side wall

: Progressive infilling of lavaka as debris aprons rise higher on slope and lavaka base narrows

: Reactivated headwall shows remnant clay painted surface and wall vegetation

: Poorly developed

: Partial vegetation in stageIII lavakas. Clay painting of bare walls indicates minimal activity in recent rainy season

: Pair of inactive lavakas

: Overhanging laterite and vertical saprolite. Recent wall-fall material has been completely removed: no debris apron at base…

: Overhanging laterite and vertical saprolite

: Overhanging headwall over collapsed lower wall

: Overhanging headwall in young active lavaka

: Overhang at top of vertical head and side walls in stage II lobe]

: Overhanging headwall and exposed Eucalyptus roots in active stage II lavaka

: Overhanging headwall (with seated geologists)

: Overhang at top of vertical head and side walls in stage II lobe]

$Overhang and fractures in active headwall$: Overhang and fractures in active headwall

: Overhang and exposed Eucalyptus roots in recently-active section of stage III complex

: Outfall showing vertical-sided incision

: Outfall picture of non-typical elongate lavaka

: Outfall channel incised in saprolite

: Old lavaka complex on hillslope

: Non-typical elongate lavaka

: Narrow

: No vertical walls remaining in large lavaka

: New lavaka cuts old road

: Nested lavakas of unusual morphology in fall valley wall

: Narrow flat floor of braided flow deposits winds between debris aprons in large active lavaka

: Multiple small lavakas in hillslope

: Multiple lavakas in landscape of convex hills

: Multiple lavakas in landscape of convex hills

: Multiple lavakas in landscape of convex hills

: Multi-septate stage III lavaka complex

: Multi-septate stage III lavaka complex

: Mostly inactive

: Mostly grassed in

: Multi-septate stage III lavaka complex

: Multi-lobed lavaka complex

: Midslope lavaka with deeply incised outfall channel

: Midslope lavaka with deeply incised outfall channel

: Mature

: Mature Eucalyptus trees in mature stage III lavaka

: Mature (coppiced) Eucalyptus growing inside lavaka

: Massive headwall of large lavaka that has cut back through ridge crest.

: Lower walls mantled by debris aprons and limited vertical walls above in mature stage III lavaka

: Low-activity lavaka (all walls clay-painted) with headwall extending back through ridge crest

: Looking from headwall toward outfall of stage III lavaka with vertical upper walls and vegetated

: Long narrow lavaka and bare ground

: Limited activity represented by bare patches at top of headwall in well-vegetated lavaka

: Lavakaed landscape

: Lavakaed landscape

: Lavaka

: Lavaka with long

: Lavaka with eroded septae preserves vertical headwall but has vegetated interior and outfall

: Lavaka sidewall no longer vertical

: Lavaka interior

: Lavaka in roadcut: grotto with overhanging headwall

: Lavaka in partially tree-covered slope. Trees are probably younger than lavaka

: Lavaka in last phases of activity. Small vertical wall sections shed small amounts of sediment

: Lavaka in convex hillslope

: Lavaka high in midslope

: Lavaka formation within a roadcut by vertical subsurface collapse

: lavaka erosion in roadcut

: lavaka erosion in roadcut

: Lavaka developed above and behind weathered/eroded roadcut

: Lavaka cutting old road

: Lavaka cut back through hill crest. New roadcut at outfall

: Lavaka complex above rizière

: Lavaka becoming invaded by pine and eucalyptus scrub

: Lavaka becoming inactive.

: Lavaka and bare ground on sparsely treed slope. Eucalyptus are younger than lavaka

: Laterite and saprolite visible in steep walls of active stage III lavaka

: Laterite and saprolite visible in steep walls of active stage III lavaka

: Largely inactive

: Largely inactive lavakas

: Largely inactive lavakas on hillslope behind village

: Largely inactive lavaka

: Largely inactive lavaka

: Largely inactive lavaka

: Largely inactive lavaka

: Largely inactive lavaka

: Large-scale polygonal cracks in surface beside large active lavaka. Bare ground with large-scale cracks like this is unusual…

: Large-scale polygonal cracks in surface beside large active lavaka. Bare ground with large-scale cracks like this is unusual

: Large-scale polygonal cracks in surface beside large active lavaka. Bare ground with large-scale cracks like this is unusual

: Large

: Large vertical pipe with grottoes and resistant (quartz-rich) layers in saprolite

: Large vertical pipe intersects surface in lavaka headwall

: Large road-cutting lavaka. Old road runs from top right to upper left

: Large plumose lavaka complex. Cows in lower left for scale

: Large midslope lavaka

: Large lavaka with narrow elongate outfall

: Large lavaka with big coherent downdropped block in interior. Very unusual morphology

: Large lavaka surrounded by bare ground erosional patches.

: Large lavaka consists of two adjacent lavakas with intervening wall almost completely removed

: Large inactive lavaka with tiny new lavaka (?3 m long) to left

: Large downdropped block in lavaka interior. May have a small rotational component

: Large block fallen from sidewall

: Large active lavaka

: Large active lavaka

: Large active lavaka

: Large active lavaka

: Landscape with several inactive lavakas

: Large active lavaka with headwall at ridge crest. Recent sand deposits in foreground

: Large active lavaka has cut back through ridge crest. New plantings on exposed sand in outfall area are a stabilisation attempt

: Landscape with lavakas of different sizes and stages of evolution

: Landscape with lavakas of different sizes and stages of evolution

: Landscape with lavakas of different sizes and stages of evolution

: Landscape with lavakas of different sizes and stages of evolution

: Landscape with lavakas at many stages of evolution

: Jane stands on fallen roof (still vegetated in base of newly-formed lavaka

: Jane points to seepage along hairline crack in saprolite

: Interior of tree-filled lavaka

: Interior of steep-walled active lavaka

: Incised outfall from large midslope lavaka

: Incised outfall channel in large lavaka

: Incised narrow outfall channel

: Interior of lightly active stage III lavaka. Retains vertical faces

: Incipient lavaka: collapse is incomplete

: Inactive

: Inactive lavaka. Erosional remnant of gneiss (outcrop lower right) is encased in saprolite

: Inactive lavaka

: Inactive lavaka with eroded diagonal (unusual!) septae

: Inactive lavaka on left (but with central bare patch showing vertical piping)

: Inactive lavaka

: LavakaImages_DC2014_003_136

: LavakaImages_DC2014_003_135

: Headwall of sporadically active lavaka: some recent falls

: LavakaImages_DC2014_003_133

: Headwall of newly-formed lavaka shows red laterite at top

: Head and side walls show both recently collapsed (very pale) and clay-painted (greyish) sections

: LavakaImages_DC2014_003_130

: Groundwater seepage in base of lavaka. Saprolite above (paler) is dry; that below (darker) is wet

: LavakaImages_DC2014_003_128

: Grottoes form in less-resistant (less quartz-rich) saprolite; blocky debris collects at base

: Grottoes and debris aprons in active lavaka

: LavakaImages_DC2014_003_125

: LavakaImages_DC2014_003_124

: Grotto in roadcut

: Grotto in roadcut

: Grotto formed by roof-down blockfall in active sidewall

: LavakaImages_DC2014_003_120

: Grassy floor (with fields) and steep walls of active stage III lavaka

: Gneissic foliation in saprolite exposed in vertical lavaka wall

: LavakaImages_DC2014_003_114

: LavakaImages_DC2014_003_118

: LavakaImages_DC2014_003_117

: Gneissic foliation preserved in multi-coloured saprolite

: Fully v-shaped lavaka with almost no remaining activity

: Fully V-shaped inactive lavaka

: Foreground shows weathered septum within stage III lavaka

: LavakaImages_DC2014_003_104

: Foreground shows weathered septum within stage III lavaka

: LavakaImages_DC2014_003_109

: LavakaImages_DC2014_003_108

: LavakaImages_DC2014_003_107

: LavakaImages_DC2014_003_106

: Fields in outfall area of old lavaka with one remaining sediment-shedding patch (on right)

: Fields in base of weathered and vegetated lavaka

: LavakaImages_DC2014_003_102

: LavakaImages_DC2014_003_101

: LavakaImages_DC2014_003_100

: LavakaImages_DC2014_003_099

: Eroded septum in sporadically active stage III lavaka

: LavakaImages_DC2014_003_093

: Eucalyptus ground in the out fall

: LavakaImages_DC2014_003_097

: Erosion of wall separating two discrete lavakas will generate a large lavaka complex

: LavakaImages_DC2014_003_095

: LavakaImages_DC2014_003_092

: LavakaImages_DC2014_003_091

: LavakaImages_DC2014_003_090

: LavakaImages_DC2014_003_089

: LavakaImages_DC2014_003_088

: Eroded septae in less-active

: Eroded septae in inactive lavaka

: LavakaImages_DC2014_003_085

: LavakaImages_DC2014_003_083

: Early stage III lavaka

: LavakaImages_DC2014_003_081

: Down-valley view of long outfall channel

: LavakaImages_DC2014_003_079

: LavakaImages_DC2014_003_078

: Eroded laterite overlying paler saprolite (foliation visible dipping to right)

: LavakaImages_DC2014_003_072

: Down-lavaka view of barely active stage III lavaka

: Down-lavaka view showing narrow winding outfall

: Down-lavaka view showing eroded septae and long outfall channel to valley floor

: LavakaImages_DC2014_003_075

: LavakaImages_DC2014_003_074

: LavakaImages_DC2014_003_073

: LavakaImages_DC2014_003_070

: LavakaImages_DC2014_003_069

: LavakaImages_DC2014_003_068

: LavakaImages_DC2014_003_067

: Development of lavaka erosion above and behind roadcut in laterite/saprolite

: LavakaImages_DC2014_003_062

: LavakaImages_DC2014_003_061

: Development of lavaka erosion above and behind roadcut in laterite/saprolite

: LavakaImages_DC2014_003_064

: LavakaImages_DC2014_003_063

: Detail of lavaka erosion in roadcut (1): grotto formed below crack from surface

: LavakaImages_DC2014_003_059

: LavakaImages_DC2014_003_058

: LavakaImages_DC2014_003_057

: LavakaImages_DC2014_003_056

: LavakaImages_DC2014_003_055

: LavakaImages_DC2014_003_054

: LavakaImages_DC2014_003_053

: LavakaImages_DC2014_003_051

: Declining activity in mature lavaka. Bare vertical faces remain

: Debris aprons

: Debris apron of recently fallen wall material

: Debris apron in large active lavaka

: LavakaImages_DC2014_003_052

: LavakaImages_DC2014_003_040

: Crestline with bites out of it: lavakas cut through ridgeline

: LavakaImages_DC2014_003_046

: LavakaImages_DC2014_003_045

: LavakaImages_DC2014_003_044

: LavakaImages_DC2014_003_043

: LavakaImages_DC2014_003_042

: LavakaImages_DC2014_003_041

: LavakaImages_DC2014_003_038

: LavakaImages_DC2014_003_037

: LavakaImages_DC2014_003_036

: LavakaImages_DC2014_003_035

: Convex hills and flat valley floor. One lavaka partly hidden on right side

: LavakaImages_DC2014_003_033

: LavakaImages_DC2014_003_030

: LavakaImages_DC2014_003_029

: LavakaImages_DC2014_003_028

: Complex of three lavakas. The rightmost lobe is essentially inactive

: LavakaImages_DC2014_003_031

: Clay-painted walls in stage III lavaka

: LavakaImages_DC2014_003_026

: Canal dug to divert (away from ricefields) sediment flows coming from active lavaka

: LavakaImages_DC2014_003_024

: LavakaImages_DC2014_003_019

: Bare ground patches and lavaka on hillslope. The bare ground patches appear in 1965 air photos

: LavakaImages_DC2014_003_023

: LavakaImages_DC2014_003_022

: LavakaImages_DC2014_003_021

: LavakaImages_DC2014_003_020

: LavakaImages_DC2014_003_017

: LavakaImages_DC2014_003_016

: LavakaImages_DC2014_003_015

: Amphitheatre view of active lavaka

: LavakaImages_DC2014_003_013

: LavakaImages_DC2014_003_012

: Active stage II lobe in stage III complex

: Active lavaka

: Active lavaka with recent debris flow entering stream in foreground

: Active lavakas. Both appear on 1965 air photos

: LavakaImages_DC2014_003_007

: Active lavaka intersecting road

: LavakaImages_DC2014_003_005

: LavakaImages_DC2014_003_004

: LavakaImages_DC2014_003_003

: LavakaImages_DC2014_003_002

: LavakaImages_DC2014_003_091

: Eroded septae in recently reactivated lavaka

: Eroded septae in old lavaka complex

: LavakaImages_DC2014_003_088

: LavakaImages_DC2014_003_087

: LavakaImages_DC2014_003_001

: LavakaImages_DC2014_003_093

: LavakaImages_DC2014_003_092

: LavakaImages_DC2014_003_080

: LavakaImages_DC2014_003_079

: Down-valley view of long outfall channel

: LavakaImages_DC2014_003_086

: LavakaImages_DC2014_003_085

: LavakaImages_DC2014_003_084

: Early stages of erosion in median septum of stage III lavaka

: LavakaImages_DC2014_003_082

: LavakaImages_DC2014_003_081

: LavakaImages_DC2014_003_077

: LavakaImages_DC2014_003_076

: Down-lavaka view showing channelised sediments in outfall

: Down-lavaka view of recent activity in stage III lavaka

: LavakaImages_DC2014_003_073

: LavakaImages_DC2014_003_072

: LavakaImages_DC2014_003_071

: Down-lavaka view of barely active stage III lavaka

: LavakaImages_DC2014_003_067

: LavakaImages_DC2014_003_066

: LavakaImages_DC2014_003_065

$Detail of lavaka erosion in roadcut (5): small grotto developed below hairline fracture (connected to surface)$: Detail of lavaka erosion in roadcut (5): small grotto developed below hairline fracture (connected to surface)

: LavakaImages_DC2014_003_063

: LavakaImages_DC2014_003_062

: LavakaImages_DC2014_003_061

: LavakaImages_DC2014_003_060

: LavakaImages_DC2014_003_059

: LavakaImages_DC2014_003_058

: LavakaImages_DC2014_003_057

: LavakaImages_DC2014_003_056

: Deeply incised

: LavakaImages_DC2014_003_054

: Deeply incised

: Deeply incised

: LavakaImages_DC2014_003_050

: LavakaImages_DC2014_003_049

: LavakaImages_DC2014_003_048

: LavakaImages_DC2014_003_047

: LavakaImages_DC2014_003_051

: Debris apron against active lavaka sidewall represents small-scale reactivation of otherwise fully vegetated lavaka

: Debris apron against active lavaka headwall

: LavakaImages_DC2014_003_044

: LavakaImages_DC2014_003_043

: Cultivation in outfall areas of vegetated

: Cultivation in outfall area of vegetated

: LavakaImages_DC2014_003_039

: LavakaImages_DC2014_003_038

: LavakaImages_DC2014_003_037

: LavakaImages_DC2014_003_036

: Convex topography and inactive lavakas

: LavakaImages_DC2014_003_034

: Cultivated outfall area of mature

: Convex hill with lavakas on two sides and bare ground on the near slope

: LavakaImages_DC2014_003_032

: Complex of coalesced lavakas

: LavakaImages_DC2014_003_030

: LavakaImages_DC2014_003_029

: Closeup of active lobe in previous picture.

: LavakaImages_DC2014_003_027

: Clay-painted wall with few recently-eroded spots

: LavakaImages_DC2014_003_025

: Blockflow or lag deposit in active lavaka. Foliation in exposed saprolite visible in headwall; debris aprons in foreground

: Blockflow in narrow throat of large active lavaka

: Big vertical wall showing piping

: LavakaImages_DC2014_003_018

: Bananas and fields in outfall area of largely inactive

: LavakaImages_DC2014_003_021

: LavakaImages_DC2014_003_020

: LavakaImages_DC2014_003_019

: Ancient lavakas

: LavakaImages_DC2014_003_015

: LavakaImages_DC2014_003_014

: LavakaImages_DC2014_003_013

: LavakaImages_DC2014_003_012

: Active lavaka with recently moved sand visible in floor of narrow twisting outfall. Erosional remnant of bedrock exposed near he

: LavakaImages_DC2014_003_006

: LavakaImages_DC2014_003_011

: LavakaImages_DC2014_003_010

: LavakaImages_DC2014_003_009

: LavakaImages_DC2014_003_008

: LavakaImages_DC2014_003_005

: LavakaImages_DC2014_003_004

: Active headwall with recent debris and blockfall deposits

: LavakaImages_DC2014_003_002

: [missing]

: LavakaImages_DC2014_003_137

: LavakaImages_DC2014_003_134

: Headward erosion of headwall

: Headwall of stage III lavaka cuts back through ridge crest

: Headwall of sporadically active lavaka

: LavakaImages_DC2014_003_132

: LavakaImages_DC2014_003_131

: Hadivory: ancient defensive village site. Surrounding ditches have become heavily eroded.

: LavakaImages_DC2014_003_129

: Grottoes in saprolite at base of active wall

: LavakaImages_DC2014_003_123

: LavakaImages_DC2014_003_122

: LavakaImages_DC2014_003_121

: LavakaImages_DC2014_003_127

: LavakaImages_DC2014_003_126

: Grotto with sediment at base of pipe in lavaka wall

: Grotto in sidewall debris apron of large lavaka

: Grotto at base of vertical crack in lavaka wall

: LavakaImages_DC2014_003_119

: Grassed-in lavaka with few vertical active sections remaining

: Grassed

: LavakaImages_DC2014_003_116

: LavakaImages_DC2014_003_115

: Gneissic foliation in saprolite exposed in vertical lavaka wall

: LavakaImages_DC2014_003_113

: LavakaImages_DC2014_003_112

: LavakaImages_DC2014_003_111

: LavakaImages_DC2014_003_110

: Foliation visible in saprolite projecting into lavaka (septum)

: Foliation preserved in saprolite in wall of active lavaka

: Foliation preserved in saprolite in vertical wall of active lavaka

: Foliation in saprolite

: LavakaImages_DC2014_003_105

: Fallen roof (flat

: Exposed saprolite

: Exposed roots extend across top of newly formed small lavaka

: Fields in flat floor of large lavaka complex

: LavakaImages_DC2014_003_103

: Eucalyptus saplings being planted in recent sandflow from active lavaka (stabilisation attempt)

: LavakaImages_DC2014_003_098

: Eucalyptus ground in the headwall

: LavakaImages_DC2014_003_096

: Eroded stumps of multiple septae in vegetated

: LavakaImages_DC2014_003_094

: Eroded septum in sporadically active stage III lavaka

: Eroded septate in lightly active stage III lavaka

: Eroded septae in side wall of lavaka

: LavakaImages_DC2014_003_090

: LavakaImages_DC2014_003_089

: Eroded septae in old lavaka complex

: LavakaImages_DC2014_003_087

: LavakaImages_DC2014_003_080

: LavakaImages_DC2014_003_086

: Eroded radial septae in stage III lavaka

: LavakaImages_DC2014_003_084

: LavakaImages_DC2014_003_083

: LavakaImages_DC2014_003_082

: Dual-lavaka complex

: Down-valley view of long outfall channel

: LavakaImages_DC2014_003_078

: LavakaImages_DC2014_003_077

: LavakaImages_DC2014_003_076

: LavakaImages_DC2014_003_075

: LavakaImages_DC2014_003_074

: Down-lavaka view of largely inactive lavaka

: Down-lavaka view of largely inactive lavaka

: LavakaImages_DC2014_003_070

: LavakaImages_DC2014_003_069

: Down-lavaka view of active lavaka with vegetated bottom and outfall. Recent sand deposits on valley floor. Fields there have…

: Different activity levels in lavakas on hillslope

: LavakaImages_DC2014_003_066

: LavakaImages_DC2014_003_071

: LavakaImages_DC2014_003_065

: LavakaImages_DC2014_003_064

: Detail of lavaka erosion in roadcut (4): erosion within fissure in saprolite

: Detail of lavaka erosion in roadcut (3): dripstone clay painting by elutriated fines

: Despite their fresh

: Detail of lavaka erosion in roadcut (2): dripstone clay painting by elutriated fines

: LavakaImages_DC2014_003_060

: Descent into lavaka

: “Demi-orange” topography

: Deeply incised

: LavakaImages_DC2014_003_055

: Deeply incised

: LavakaImages_DC2014_003_053

: LavakaImages_DC2014_003_052

: Deeply incised

: LavakaImages_DC2014_003_050

: LavakaImages_DC2014_003_049

: LavakaImages_DC2014_003_048

: LavakaImages_DC2014_003_047

: LavakaImages_DC2014_003_046

: LavakaImages_DC2014_003_045

: Debris apron (foreground) and saprolite with foliation (background)

: LavakaImages_DC2014_003_040

: LavakaImages_DC2014_003_039

: Dark patches in pale saprolite represent water seepage in active lavaka wall

: LavakaImages_DC2014_003_042

: LavakaImages_DC2014_003_041

: Cracks and vertical pipes in side and headwall of active lavaka.

: Crack behind active headwall: probable site of next season’s wallfall

: Crack behind active headwall: probable site of next season’s wallfall

: LavakaImages_DC2014_003_035

: LavakaImages_DC2014_003_034

: LavakaImages_DC2014_003_033

: LavakaImages_DC2014_003_032

: LavakaImages_DC2014_003_031

: Closeup of enclosed grotto in wall of active lavaka

: LavakaImages_DC2014_003_028

: LavakaImages_DC2014_003_027

: Closeup of erosion in saprolite at base of headward-eroding lavaka

: LavakaImages_DC2014_003_026

: LavakaImages_DC2014_003_025

: LavakaImages_DC2014_003_024

: LavakaImages_DC2014_003_023

: LavakaImages_DC2014_003_022

: Big lavaka

: Big lavaka cuts back through ridge crest. Headwall was already in this position in 1965 air photos

: Big lavaka cuts back through ridge crest. Headwall was already in this position in 1965 air photos

: LavakaImages_DC2014_003_018

: LavakaImages_DC2014_003_017

: LavakaImages_DC2014_003_016

: Ancient lavakas

: LavakaImages_DC2014_003_008

: LavakaImages_DC2014_003_014

: Active vertical faces in early stage III lavaka. Blackened surfaces are burnt grasses

: Active stage II lobe in stage III complex

: LavakaImages_DC2014_003_011

: LavakaImages_DC2014_003_010

: LavakaImages_DC2014_003_009

: LavakaImages_DC2014_003_007

: LavakaImages_DC2014_003_006

: Active lavaka in meander bend of river

: Active lavaka in head of ancient equilibrated lavaka (note convex slopes of old lavaka walls)

: LavakaImages_DC2014_003_003

: Active head- and sidewall erosion

: 5m Eucalyptus growing on older debris pile on left

: DSC_0653

: DSC_0652