Depositional Signatures Associated with Late-Stage Transgression and the Mid-Holocene Sea-Level Highstand in BrazilChristopher J. Hein1 (hein@vims.edu), Duncan M. FitzGerald2 , J. Thadeu Menezes3, Antonio H.d.F. Klein4, Marcio B. Albernaz5, William J. Cleary6

1Department of Physical Sciences, Virginia Institute of Marine Science, College of William and Mary, Gloucester Point, VA, USA; 2Department of Earth and Environment, Boston University, Boston, MA USA; 3Laboratory of Geological Oceanography, UNIVALI - CTTMAR, Itajaí, SC, BRAZIL; 4Department of Geosciences, Federal University of Santa Catarina, Florianópolis, SC, BRAZIL; 5Tetra Tech, São Paulo, BRAZIL;

6Center for Marine Science, University of North Carolina at Wilmington, Wilmington, NC, USA

Abstract ID: 249114

5. Example Site: Navegantes Strandplain, Santa Catarina

4. Classification of Highstand Deposits

1. Motivation: Coastal Response to Transgression &

Highstand

2. Holocene Sea-Level Change 3. Mid-Holocene Highstand Deposits

7. Acknowledgments

6. Conclusions & Implications

8. References

AssociatedManuscript

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Partial funding provided by the donors of the American Chemical Society Petroleum Research Fund. Additional funding provided by FAPESC / Prof. Number 16247/2007-7, CNPQ Proc. Number 575008/2008-3. A.H.F. Klein thanks CNPQ for the Research Fellow PQ-2, Proc. Numb.300153/ 2009-0. We also thank CTTMAR / PROPEC / UNIVALI for institutional support and the following individuals for assistance with field data collection: M. Berribilli, T. Scolaro, D. Neto, G. Silva, C. Brandl, & R. Sangoi. B. Schwartz (Boston University) provided assistance with laboratory data analysis.

Holocene Evolution of Brazilian Coast Controlled by RSL Change:

Early Holocene (> 7 ka): transgression erodes Pleistocene uplands & ancient (~120 ka) regressive shorelinesMid-Holocene (7–5 ka): SL highstand & deposition of transgressive lagoons & backbarrier deposits, transgressive bars, & barrier complexes Late Holocene (5–1 ka): coast largely smoothed by deposition of broad strand-plains during forced regression

Brazilian Holocene Highstand Deposits:Three end members of deposits: Backbar-rier Deposits, Transgressive Barrier Ridge / Bar, & Barrier Island ComplexesDeposits nonexistent: Exposed Bedrock Coast at highstandMany sites contain >1 type; features often possess characteristics of >1 typeHighstand features reflect relative sediment supply (fluvial, offshore, in situ reworking) and UMP (controlled by ante-cedent topography, wave energy) at given site during mid Holocene

Implications for Coastal Response to Accelerated SL Rise & Transgression:

SLR acceleration to up to 16 mm/yr by 2100 (Church et al., 2013)Coastal response will be non-linear:

Threshold SLR rate for barrier stability at mid-Holocene in Brazil: 2.0 mm/yr

Barriers rapidly migrate during early Holocene when SLR at 2–2.5 mm/yrBarriers only stabilize once SLR de-celerates to <1.5–2.0 mm/yr (5–6 ka)

Coastal response will be non-uniform: Site specificity of conditions associated with the formation of each highstand deposit type in BrazilGreat diversity (three highstand deposit types) identified even within a single small embayment (Navegantes)

Site #1: Highstand Type A (Exposed Bedrock Coast)

Distance (m)

-2

2

4

0Seaward (East)Landward (West)

Elev

atio

n (m

MSL

)

msl

150120906030

NVV16 NVA13

Strandplain

Modern Soil / Road Fill

Bedrock

Explanation

medium sand

coarse sand

modern MSL

fine sand

silt

organicsclay

shell-rich sand

heavy-mineral-rich sand

radargram reflection traces

bedrockFig. 7. Processed (above) & interpreted (below) ground-penetrating radar (GPR) radar-grams from Navegantes sites 1-3 (see Fig. 6 for locations). GPR profiles representative of signatures of 3 types of highstand deposits found along Brazilian coast. Graphic core logs from auger cores (NVA-xx), vibracores (NVV-xx), & wash-boring cores. msl - mean sea level; m MSL - meters above mean sea level

3 types of highstand features found at Navegantes:Site #1: no highstand deposits (Type A); waves crashing along exposed bedrock at highstandSite #2: barrier ridge (TYPE C) pinned to bedrock platform at highstand; resistant bedrock prevented upland migrationSite #3: Pleistocene upland eroded by waves during trans-gression; segmented highstand barrier island (TYPE D) with washover unit overlies thin transgressive lagoon (dated: 6.7 ka)

Highstand Ridge Strandplain

Bedrock

Modern SoilNVV14

NVV15

Upland Aeolian Sand

? ??

Distance (m)

-2

2

4

0Seaward (East)Landward (West)

Ele

vatio

n (m

MS

L)

300200100

6

msl

NVV10 NVA11 NVA12 NVV12 NVV11 NVV13

Site #2: Highstand Type C (Transgressive Barrier Bar)

Distance (m)

-2

2

4

0Seaward (East)Landward (West)

Ele

vatio

n (m

MS

L)

300200100

6

msl

B

Transgressive Lagoon: 6756 ± 41 cal yr BP45200 ± 1200

uncal yr BP45500 ± 870 uncal yr BP

Distance (m)

-2

2

4

6

0 50 100 150

Elev

atio

n (m

MSL

)

msl

Seaward (South)Landward (North)

Barrier Ridge Strandplain

Pleistocene Upland

Modern Soil NVV09NVV08

NVV07 NVA08

Distance (m)

-2

2

4

6

0 50 100 150

Elev

atio

n (m

MSL

)

msl

Seaward (South)Landward (North)

Site #3: Highstand Type D (Barrier Island Complex)C

A

Developed Property

Topographic Ridge

NVA7

NVA8

NVV7

NVV9

NVV8 NVV6

NVA6

NVA5

GPR Transect (Fig. 7b)

RTK GPS Region (Fig. 6d)

100 m

N

NVV11

NVV10

NVV12

NVA11

NVA12GPR Transect

(Fig. 7c)

100 m

NVV13

NVV14NVV15

Vibracore

Ground-penetrating radar (GPR) profile

Auger core

Wash boring core

N

GPR Transect (Fig. 7a)

NVV16NVA13

N

100 m

Extent of exposed bedrock

B

D

C

NVA14

Navegantes Holocene

Strandplain

Bedrock

Pleistocene / Upland

River / Anthropogenic

Modified

Bedrock

City of Navegantes

City of Itajaí Bedrock

Headlands

Bedrock Headland

Itajaí River

Site 3

3 km

N

48o 40’ W

26o 55’ S

26o 50’ S

48o 35’ W

48o 40’ W

Site 1

Site 2

Sediment cores

GPR Profiles

Strand lines

Area of Detail

(Navegantes)

Santa Catarina Island

São Francisco

do Sul River

Santa Catarina

State

Paraná State

Florian-opolis

27o S

26o S

48o W

A

20 km

50 m

N

25 m

Ridge Gap (paleo-inlet?)

Lowland (paleo-

lagoon?)

80 m

Barrier RidgePleistocene

Upland

Pleistocene Upland

Regressive

Strandplain

Digital Terrain Model Vertical Scale

5.22.8 ModernElevation (m)

E

Fig. 6. A) Overview map of Navegantes, showing location of Sites 1-3 (B, C, & D, respectively) studied for evidence of highstand features. E) Digital terrain model of barrier-ridge topography at Site #3. Topographic data derived from interpolation of ~8200 RTK-GPS data points.

Site #1

Site #2

Site #3

Explanation

Navegantes Overview MapStudy Site & Data Collection

Results: 3 Types of Highstand Deposits at Navegantes

Upland Migration Potential (UMP)

Sed

imen

t Sup

ply

Type A: Exposed Bedrock Coast

Type B: Backbarrier Deposits

Type D: Barrier-IslandComplex

Type C: Transgressive Barrier Ridge / Bar

High Slope

Low Slope

waves crash along bedrock shore

horizontally-bedded reworked shoreface deposits

bedrock

NOT TO SCALE

progradational strandplain

highstand barrier bar / ridge

bedrock / Pleistocene upland deposits

progradational strandplain

relict tidal creek / lagoon

marshhighstand

barrier island

Pleistocene upland deposits

washover deposits

transgressive peat / lagoonal deposits

progradational strandplain

Pleistocene upland deposits

transgressive peat / lagoonal deposits

low-profile ridge (landward-most regressive strandplain beach ridge)

Fig. 5. Classification scheme for mid-Holocene highstand deposits preserved & identified along Brazilian coast. Draw-ings represent morphologies of coastal systems ~100 years after mid- Holocene highstand, following initiation of RSL fall, forced regression, & shoreline progradation. Four site catego-ries are defined:A) lack depositional evidence of mid-Holocene highstand.B) contain backbarrier paleo-lagoon and paleo-estuarine deposits. C) contain transgressive ridges or bars.D) contain welded transgres-sive-regressive barriers with backbarrier deposits and/or complete highstand barrier complexes.

Highstand Deposits Classified By:Sediment Supply - fluvial, shelf sources; reworking of previous sediments; coastal processes Upland Migration Potential (ability of transgressive deposits to migrate landward) - slope of upland, erodibility (bedrock vs. unconsolidated)

Additional Considerations:Deposits fall along continuum → deposits can contain aspects of multiple types Highstand deposit records reflect degree of preservation and depth / breadth of scientific study

Area of Detail

Brazil

Paraná

Rio Grande do Sul

Santa Catarina

São Paulo

Espirito Santo

Rio de Janeiro

ParáMaranhão

Amapá

Bahia

SergipeAlagoas

Pernambuco

CearáRio Grande

do Norte Paraíba

Piauí

Bragança Peninsula(5.9 ka; +1.4 to -1.5 m)

Açu River Mouth(5.9-7.1 ka; 1-2 m)

São Bento-Caiçara do Norte(6.7-7.1 ka; 1.6 m)

Marajó Island(6.1–6.3 ka)

1000 km

N

Recife Strandplain(5.6-6.2 ka; 0-2 m)

Candeías Strandplain(4.9-6.4 ka; 0.5-2.5 m)

Alagoas Coastal Plain(5.2-6.5 ka; 0.1-1.5 m)

São Francisco River Coastal Plain(5.3-5.9 ka; ~4 m)

Sergipe Strandplain (no published elevation or chronologic data)

Jequitinhonha River Plain(6.1-7.9 ka; 4 m)

Caravelas Strandplain(5.1-6.8 ka; ~2.5 m)

Doce River Coastal Plain(5.1-7.6 ka; 4 m)

Paraíba do Sul River Coastal Plain (4 m)Cabo São Tomé (5.0-6.0 ka; 5.5 m)

Itaipuaçu / Maricá Strandplain (6.5-7.2 ka)

Central Rio Grande do Sul Coastal Plain (4-5 m)Cidreira (7.3 ka; >2 m)

Jardim do Éden (6.5-6.8 ka; >2 m)

Tramandaí (5.4-7.4 ka; ~4 m)

Curumin (3.3-7.2 ka)

Southern Santa Catarina Coastal Plain (5-7 ka; >2 m)Pinheira Strandplain (>5.6 ka; >3 m)Tijucas Strandplain (5.9-6.1 ka; 4.5-5.0 m)

Navegantes Strandplain (6.6-6.9 ka; 3.5-4.5 m)

Cananéia-Iguape / Ilha Comprida (5.0-6.2 ka; 2.6-4.1 m)Jacarepaguá Coastal Plain (5.7-6.2 ka)

Paranaguá / Superagui / Pecas / Guaratuba (4.2-6.4 ka; 3.5-5.0 m)Itapoá Coastal Plain (5.4-6.6 ka; >2 m)

Explanation: Highstand Deposit TypesType C Type DType A Type B

Fig. 4. Locations of Holocene highstand deposits along Brazilian coast. Parentheses: reported ages associated with highstand deposits & elevations of highstand deposits. List of references used in compila-tion given in handout. Highstand deposit types refer to Fig. 5.

Summary of Deposits: 28 sites along Brazilian coastElevations: 0 to > 5 m above modern mean SLAges: ~4-7 ka

Nature of Deposits: Fronted by regressive strand-plains or progradational barrier depositsBackbarrier deposits: tidal flats, channels, & deltas, lagoonal sediments, marsh, subtidal & in-tertidal shoalsBarrier deposits: beach, dunes, spits, washover, etc. Shoreface deposits: subtidal & intertidal bars / shoals

4

2

0

7 6 5 4 3 2 1 0Ele

vatio

n (m

MS

L)

Age (ka B.P.)

4

2

0

7 6 5 4 3 2 10 Ele

vatio

n (m

MS

L)

Age (ka B.P.)

4

2

0

7 6 5 4 3 2 1

0

Ele

vatio

n (m

MS

L)

Age (ka B.P.)

2

0

6 5

Ele

vatio

n (m

MS

L)

Age (ka B.P.)

PR

RS

SP

MG ES

RJ

BA SE

AL

500 km

30o S

N

40o W50o W

20o S

10o S TO

SC

MS

GO

MAPA CE

PI

RNPB

PE

AP

60o W

Eq.

0

0

AB

C

D

10o N

Holocene Sea-Level Trends Along Brazilian Coast:• Changes driven by inter-hemispheric glacio-hydroisostatic forcing• Early Holocene: SLR @ 2–2.5 mm/yr• SL reaches modern levels at 6.9–7.7 ka & continues to rise • Middle Holocene (5.5–6.0 ka): RSL highstand @ 1–4 m above

modern mean SL• Late Holocene: RSL fall; reaches modern elevations < 1000 yrs. ago• Trends consistent across coast (Figs. 2, 2), except in NE Brazil

(proximal to Amazon River) where existence of highstand in debate

SL Changes Allow Preservation of Deposits:• Forced regression during RSL fall → accumulation of strandplains &

progradational barriers seaward of highstand deposits• Preservation of late-stage transgressive (7.7–6.0 ka) & highstand

(5.5–6.0 ka) deposits landward of modern shoreline

Fig. 2. Holocene sea-level curves. Modified from: (A) Cohen et al., 2005; Souza-Filho et al., 2006, 2009; (B) Caldas et al., 2006; (C) & (D) Angulo et al., 2006.

6543210

30o

Ele

vatio

n (m

MS

L)

Latitude (deg South)25o20o15o10o5o0o

Marajó, Pará (Mörner, 1999)

Caeté, Maranhão (Cohen et al., 2005)

RioGrande do Norte Coast (Bezerra et al., 2003)

Paraíba Coast (Dominguez et al., 1990)

Salvador, Bahia (Suguio et al., 1985)

Itacaré / Ilhéus, Bahia (Suguio et al., 1985)

Angra dos Reis / Parati, Rio de Janeiro (Suguio et al., 1985)

Santos, São Paulo (Suguio et al., 1985)

Cananéia / Iguape, São Paulo (Suguio et al., 1985)

Paranguá, Paraná (Angulo & Suguio,1995) Paranguá, Paraná

(Angulo & Lessa,1997)

Paranguá, Paraná (Suguio et al., 1985)

Itajaí / Laguna, Santa Catarina

(Suguio et al., 1985)

Itajaí / Laguna, Santa

Catarina (Angulo et al., 1999)

Itapoá, Santa Catarina (Souza et al., 2001)

Fig. 3. Compilation of the elevation of the mid-Holocene highstand along the Brazil-ian coast, by latitude (modified & updated from Angulo et al., 2006).

This presentation is associated with the published manuscript:

Hein, C.J., FitzGerald, D.M., Cleary, W.J., Klein, A.H.F., de Menezes, J.T., Albernaz, M.B., 2014. Coastal response to late-stage transgression and sea-level highstand. Geological Society of America Bulletin, v. 126, no. 3/4, p. 459-480.

Importance of Sedimentologic Records of Past Sea-Level Changes:

• Understanding coastal response to change in rate of sea-level rise (SLR) crucial to predicting response to modern accelerated SLR.

• Coastal features associated with past transgressions (landward translation of shoreline) & relative-sea-level (RSL) highstands provide insight into rates & nature of coastal response to RSL change.

Approach:• Transgressions → erosional: ° Due to RSL rise and/or net local erosion° Low preservation potential of deposits° Deposits associated with post-glacial

transgression in Northern Hemisphere removed by SLR during late Holocene

• Late-Holocene SL fall in S. Hemisphere:° In presence of abundant sediment

supplies, RSL fall along Brazilian coast resulted in formation of extensive strandplains & progradational barriers seaward of highstand shorelines (Fig. 1).

° Ideal location to investigate late-stage transgressive & highstand deposits formed in SLR regime similar to today & in coming century

Fig. 1. Caravelas Strandplain, Bahia, Brazil (image: NASA Visible Earth)