Archaeological implications of a widespread 13th Century tephra marker across the central Indonesian Archipelago
Introduction
Globally, there are few examples where exceptionally large-magnitude eruptions have catastrophically impacted upon early historical human populations. The obvious examples are the eruption of Santorini (Thera) that extinguished the Cycladian Maritime culture in the eastern Mediterranean during the late Bronze Age (between c. 1662 and c. 1599 B.C., Bronk Ramsay et al., 2004), the 79 A.D. eruption of Vesuvius that destroyed the Roman towns of Herculaneum and Pompeii, the Terra Blanca Joven (TBJ) eruption of Volcán llopango in El Salvador between 440 and 550 A.D. that may explain an episode in Mayan history known as the Classic Period Hiatus (Dull et al., 2001, Dull et al., 2010) and the closely spaced eruptions of Tambora and Krakatoa in Indonesia whose direct and indirect effects resulted in widespread loss of life in 1815 and 1883 A.D., respectively. In this study we report upon a mid-13th Century eruption whose products are widely distributed across the central Indonesian archipelago, and like the Tambora 1815 A.D. eruption is likely to have had significant and far-reaching effects not only upon those populations residing around the eruptive centre itself but also those living hundreds of kilometers away on adjacent and down-wind islands. At the time of this 13th Century eruption, competing kingdoms flourished over large swathes of the western and central Indonesian archipelago with sophisticated networks of trade and commerce, and constructing elaborate temple complexes often with stone inscriptions and iconography that detailed religious doctrine, deities, rulers and their successors, military campaigns, and providing some limited insight into the socio-political conditions of the time. The purpose of this study is first to document the widespread occurrence of this 13th century eruptive event across east-central Java, compare its distribution with that of the Tambora 1815 A.D. eruption and its effects, and then explore the possible connection between this Samalas eruptive event and any archaeological evidence that might elude, either directly or indirectly, to the effects of this earlier widespread eruption.
Section snippets
Background
In the mid-1990's a centimeter-thick, yellow-brown coloured, vitric-rich tephra bed of fine ash grade was identified on the flanks of Merapi Volcano (Fig. 1) inter-bedded with locally sourced fall- and flow-units of late Holocene age. It was quickly recognized that this tephra (then informally named Muntilan tephra (Andreastuti, 2000, Andreastuti et al., 1996, Andreastuti et al., 2000)) was not sourced from Merapi Volcano on account of its unique mineralogy, glass geochemistry and consistent
Merapi Volcano (∼660 km from eruptive source)
At all localities on the flanks of Merapi Volcano (Fig. 1) and irrespective of their elevation with respect to the present-day summit, Muntilan tephra has a consistent yellow-brown colour, fine ash texture and thickness (2–3 cm) (SI Fig. 1). Here, Muntilan tephra is typically enveloped by centimeter-thick pumiceous and scoriaceous lapilli beds with ashy-pumiceous-medial andic soil inter-beds (Andreastuti, 2000, Andreastuti et al., 1996, Andreastuti et al., 2000). At many southern flank
Chronology
A total of eight radiocarbon samples have so far been obtained from Merapi and Ijen Volcanoes enabling minimum and maximum (bracketing) ages to be determined (Fig. 3; Table 1; SI Material 1.0). At many sites on the flanks for Merapi Volcano, Muntilan tephra is enveloped by PDC deposits (<20 cm thick), which often contain fine-grained charred plant debris. Two dates of c. 1249 ± 19 cal. A.D. (818 ± 28 14C years B.P., OZ-T978) and c. 1277 ± 46 cal. A.D. (780 ± 50 14C years B.P., Wk-4404) were
Glass shard geochemistry and correlation
Glass shard major element determinations (SI Material 2.0) were conducted on proximal occurrences of Samalas Tephra (Phase 4) on the north-western and northern coast of Lombok. Correlatives from Merapi, Bromo and Ijen (previously named Muntilan tephra (Andreastuti, 2000, Andreastuti et al., 2000)) were also analysed for comparative purposes (Fig. 4, Fig. 5; Table 2; see SI Table 1). Results from distal and proximal Muntilan tephra are indistinguishable and showing a consistently broad
Glass shard morphology
Backscatter imaging of glass shards from proximal to distal sites reveal strong morphological similarities. Typically the shards are highly vesicular with thin arcuate-shaped walls. As previously noted (Vidal et al., 2015) sub-micrometer-sized crystal inclusions of Fe-Ti oxides, feldspars and pyroxenes occur dispersed within the glassy matrix. Another obvious feature of proximal to distal occurrences of Samalas Tephra are conspicuous aggregates of finely comminuted glassy fragments adhering to
Distribution
Thickness values for Muntilan tephra across Java vary from ∼2 to 3 cm at Merapi Volcano (∼660 km west of eruptive source) to 15 cm at Bromo (∼380 km) and a maximum thickness of 22 cm at Ijen (∼240 km) (Fig. 6A). With the exception of Merapi occurrences where multiple and consistent measurements were made – Muntilan tephra at Kelut, Bromo and Ijen are laterally discontinuous and where present exhibit bedding features indicative of anthropogenic disturbance (Kelut), overthickening either by
The Tambora eruption analogue
In the aftermath of the exceptionally large and widespread Samalas eruption occurring in 1257 A.D. at Rinjani Volcanic Complex (RVC) on Lombok Island (Lavigne et al., 2013), it is very likely there was considerable westward disruption to subsistence agriculture, food shortages and famine, dislocation of affected populations, trade disruption and socio-political unrest over large areas of the central Indonesian archipelago on a scale that equalled or even exceeded the catastrophic effects
The utility of Samalas Tephra for inter-regional archaeological studies
The distinct lack of archaeological references within those realms that might associate the expected effects of the largest tropical eruption of the last two millennia to socio-political events of that time is both surprising and inordinately frustrating. However, the physical occurrence of the tephra itself may be just as important for the dating of equivalent-aged sequences that are intimately associated with contemporary or earlier archaeological sites and structures. Currently there are at
Acknowledgements
This research originates from a PhD related fieldwork conducted by SA and supervised by BVA under a NZODA study award as part of a Development Cooperation Programme between New Zealand and the Republic of Indonesia. The PhD scholarship awarded to SA was provided by the New Zealand Ministry of Foreign Affairs and Trade (MFAT). Dr's Wimpy Tjetjep, R. Sukhyar, M.A. Purbawinata, and A. Ratdomorpurbo, are all thanked for their contributions to, and support of, this PhD research in the late 90's. The
References (33)
- et al.
Preliminary stratigraphy and geochemistry of mid to late Holocene tephra beds from Merapi Volcano, central Java, Indonesia
J. VolcON. Geotherm. Res.
(2000) - et al.
New estimates of the 1815 Tambora eruption volume
Journ. Volcanol. Geotherm. Res.
(2014) - et al.
Reconnaissance pyroclastic stratigraphy of Merapi volcano, central Java: >7,000 years of explosive eruptions
Journ. VolcON. Geotherm. Res.
(2000) - et al.
Proxy evidence for an El Nino-like response to volcanic forcing
Nature
(2003) Stratigraphy and geochemistry of Merapi Volcano, Central Java, Indonesia: Implications for the Assessment of Volcanic Hazards
(2000)- et al.
Preliminary stratigraphy and geochemistry of mid to late Holocene tephra beds from Merapi Volcano, central Java, Indonesia
- et al.
Programme and field guide for the coordinating committee for geoscience programmes in east and southeast Asia (CCOP)
- Anonymous, 1265. Chronica minor Auctore Minorita Erphordiensi, Societas Aperiendis Fontibus Rerum Germanicarum Medii...
- et al.
Dating the volcanic eruption at Thera
Radiocarbon
(2004) - et al.
Volcanism, ecology and culture: a reassessment of the Volcán Ilopango TBJ eruption in the southern Maya realm
Lat. Am. Antiq.
(2001)