Stepping Stones or Barrier: The Role of Far Southeastern Pacific Islands in Pacific Ocean Prehistory

Transcription

1 Stepping Stones or Barrier: The Role of Far Southeastern Pacific Islands in Pacific Ocean Prehistory Simon Haberle*, Atholl Anderson, Gloria Rojas, Andrea Seelenfreund, Mauricio Massone & Jose Miguel Ramirez *Department of Archaeology and Natural History, College of Asia and the Pacific, Australian National University

2 Climates for Change in the Pacific Mean annual precipitation Maldives Philippines Palau Papua New Guinea Solomon Islands Hawaii Galapagos Islands Mascarenes Atherton Fiji Vanuatu Australs Juan Fernandez Arch. Isla Santa Maria Current projects at ANH combining palaeoecology and archaeology Geoff Hope, Mat Prebble, Nick Porch, Janelle Stevenson

3 Eastern Pacific Islands Project Stepping stones or barriers for human migration? Galapagos Islands Isla Coco Easter Island Desventuradas Islands Juan Fernandez Islands Isla Santa Maria Isla Mocha Poster by Ashley Natt et al. 28 Yrs of El Nino and Human Impact in the Galapagos Islands

4 Eastern Pacific Islands Project Stepping stones or barriers for human migration? Galapagos Islands Isla Coco Easter Island Desventuradas Islands Chicken brought to Chilean coast around 62 yr ago (Storey et al. 27) Juan Fernandez Islands Isla Santa Maria Isla Mocha El Arenal

5 Key Issues Can we identify in our palaeoecological reconstructions of past environmental change impacts from different cultural groups (e.g. Polynesian from Amerindian)? Need to be able to distinguish in the biotic record processes associated with different modes of human activity - requires records with temporal and spatial resolution comparable to processes being examined (~decadal) - requires taxonomic resolution to species level

6 Juan Fernandez Archipelago No evidence for pre-colombian occupation of the Juan Fernandez Arch.

7 Pollen Record from Robinson Crusoe Island Plazoleta del Yunque lowland forest (3 m alt.) Sediment Column Depth (cm) Forest Herbs Ferns Chonta Palm Canelo Luma Naranjillo Grass Blackberry Eucalypt Bat s Wing Fern Charcoal PCA Axis 1 Axis 2 55/-5 5 BP 36/-5 BP /-5 BP /-5 BP % 1-2

8 Pollen Record from Robinson Crusoe Island Plazoleta del Yunque lowland forest (3 m alt.) Sediment Column Depth (cm) Forest Herbs Ferns Chonta Palm Canelo Luma Naranjillo Grass Blackberry Eucalypt Bat s Wing Fern Charcoal PCA Axis 1 Axis 2 55/-5 5 BP 36/-5 BP /-5 BP /-5 BP % 1-2

9 Regional Vegetation Change 33 BP 3 BP 8 BP European period 55 BP 14 BP Altitude (m) Tree line Inocentes La Piña 55 BP 36 BP Forest Herbs Ferns Charcoal 2 Plazoleta del Yunque 79 BP 93 BP

10 Pre-Ceramic Archaic Period 1-2 BP Talcahuanense Monte Verde D. Quiroz & M. Sánchez (24) Chanchanense

11 Early Ceramic Pitren Complex: 6 AD Isla Mocha Chiloe D. Quiroz & M. Sánchez (24)

12 Late Ceramic El Vergel Complex: 1-15 AD Isla Santa Maria El Arenal Isla Mocha Chiloe D. Quiroz & M. Sánchez (24)

13 Isla Mocha Human occupation: ~35- BP D. Quiroz & M. Sánchez (24)

14 Isla Santa Maria Human occupation: ~1 BP

15 Archaeological Record from Isla Santa Maria Site SM-6 SM-6 SM-11 SM-25 SM-26 SM-26 SM-26 SM-29 SM-29 SM-3 Age ( 14 C seed /TL pot ) BP* 91 4 BP Pollen core *Chenopodium quinoa from SM-29 Mauricio Massone, Claudia Silva & Rafael Labarca (28) 1mm

16 Pollen Records from Isla Santa Maria

17 Pajonal de la Dolores Depth (cm) sample AMS C Dark brown course organic detritus Brown fine organic detritus/clay 95 /- 3 BP Macro Charcoal light >125µ m dark >25µ m Micro Charcoal <125 m µ Introduced trees Native Trees and Shrubs Herbs Pinus Eucalyptus Asteraceae (Lig.) Asteraceae (Tub.) Chenopodiaceae Poaceae Cyperaceae Solanum C B 1 Hispanic El Vergel B /- 3 BP 1 Brown-grey clay with banded sand A Pre-settlement /- 3 BP Grey sand 1 4 % = present <1%

18 Depth (cm) 2 Puerto Sur, Isla Santa Maria 14 AMS C sample Dark brown course organic detritus 1.5 /-.3 %M Macro Charcoal light >125µ m dark >25µ m Micro Charcoal <125µ m Introduced trees Native Trees and Shrubs Herbs Pinus Eucalyptus Cerealia Cyperaceae Poaceae Chenopodiaceae Asteraceae (Tub.) Solanum Zea mays Typha C Hispanic 4 Brown fine organic detritus/clay B 1 El Vergel 15 /- 3 BP 6 B 2 Brown-grey clay with banded sand 1 8

19 Age-Depth profiles: Comparison of Archaeo-Palaeo records Depth (cm) Stratigraphy & AMS sample 2 15 Calibrated Age (AD) 1 5 PALAEOECOLOGICAL INTERPRETATION Pollen Zones Hispanic 2 4 El Vergel Pre-settlement Hispanic El Vergel Pre-settlement ARCHAEOLOGICAL INTERPRETATION

20 Key Issues Can we distinguish Polynesian from Amerindian settlement? What might we expect to see? Partial footprints from both groups? Selective exchange of material culture, crops etc? Chronology is critical Striving for maximum resolution (temporal and spatial) is essential in arguing cause and effect of climate change on human society through time

21 Key Issues Climate Change 1 6 Glacial-Interglacial Cycles Millennial Climate Fluctuations ENSO-related variability Temporal Scale (yr) 1 3 Extinction Speciation Domestication Migration Evolution Seasonality Settlement patterns Forest Clearance 1 Species Genera Family Kingdom Taxonomic Scale

22 Conclusions The far eastern Pacific Islands provide an exciting opportunity to examine the response of island ecosystems to different modes of human activity (interactions between different cultures) Developing high-resolution methods to enable us to distinguish in the biotic record processes associated with different modes of human activity Rigorous hypothesis testing will be required to move the debate forward

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24 Chrononzones Antarctica Pilgerodendron uviferum-type Age cal yr BP Holocene Younger Dryas Allerod Older Dryas Bolling ACR Trees & Shrubs Herbs Ferns Pilgerodendron uviferum-type Trees & Shrubs Herbs Ferns FACIL STIBNITE

25 Gunnera Philesia Rubia Cruciferae Convolvulaceae Solanum Galium Liliaceae Elytropus Onagraceae Ophioglossum Trilete psilate Monolete psilate Azolla Unidentified Total sum Native Trees and Shrubs Herbs Pinus Eucalyptus Alnus Aextoxicon Podocarpus Amomyrtus Myrceugenia Griselinia Maytenus Asteraceae (Tub.) Chenopodiaceae Poaceae Cyperaceae Osmorrhiza Umbelliferae Labiatae Bowelesia Haloragis Polygala Hydrocotyle Passiflora Valeriana Limnobium Asteraceae (Lig.) Polypodium Sporormiella Introduced trees Depth (cm) Pajonal de la Dolores, Isla Santa Maria 14 AMS C sample Magnetic Susceptibility (k) Macro Charcoal light >125mm dark >25mm Dark brown course organic detritus Brown fine organic detritus/clay 95 /- 3 BP 129 /- 3 BP Brown-grey clay with banded sand 22 /- 3 BP Grey sand Micro Charcoal <125mm 1 PD-4 PD-3 PD-2 PD-1 = present <1% Analysis by Simon Haberle 28

26 Podospora Total sum Depth (cm) Puerto Sur, Isla Santa Maria 14 AMS C sample Magnetic Susceptibility (k) Dark brown course organic detritus 1.5 /-.3 %M Brown fine organic detritus/clay 15 /- 3 BP Brown-grey clay with banded sand Macro Charcoal light >125 µ m dark >25 µ m Micro Charcoal <125 µ m PS-3 PS-2 PS-1 Aextoxicon Drymis Griselinia Maytenus Grevuina Croton Cyperaceae Gunnera Poaceae Osmorrhiza Chenopodiaceae Onagraceae Cissus Rumex Asteraceae (Microseris type) Bowelesia Labiatae Loranthaceae (Psittacanthus type) Asteraceae (Tub.) Asteraceae (Mutisia type) Solanum Zea mays Gesneriaceae (Mitraria type) Caryophyllaceae Cruciferae Asteraceae (Lig.) Typha Monolete psilate Polypodium Dryopteris Ophioglossum Trilete psilate Azolla Unidentified Sporormiella Myrceugenia Pinus Eucalyptus Cerealia Amomyrtus Native Trees and Shrubs Herbs Introduced trees

27 Medieval Warm Period Little Ice Age