Geoarchaeology

Question 1

Stastics of the 25/04/2015 Ghorka Earthquake (11:56am)

Answer 1

• 7.8Mw Magnitude
• Over 9000 killed
• 20,000 injured
• 500,000 homes destroyed
• 691 historic monuments damaged, 131 collapsed
• 32% cancellation of tourist visits

Question 2

Geoarchaeology toolkit
- Conceptual tools
- Analytical tools

Answer 2

Conceptual tools:
- Geoscience applied into archaeology
- Soil and sediments
- Stratigraphy
- Landscape

Analytical tools:
- Field stratigraphies
- Chronological frameworks
- Cultural soil/sediment formation

Question 3

Kasthmandap - what did the earthquake do, and what did it reveal about the building?

Answer 3

• Cleared site back to its foundations
• Cross walls lined with infilled soil and sedimentary materials
• Stones with holes = saddle stones, held pillars
• Organised in a unit of 9: each square revealed an element of the Hindu cosmos
• Ritual element embedded within the foundations
• Organised as a mandala

Question 4

Different chronologies of Kasthamandap

Answer 4

• Scholars have suggested the foundation/construction to have been in/around C12th AD
• Others suggested 1596 AD
• Based on revealed foundations, archaeologists determine first phase of foundation at 600-750 AD, second phase at 800 AD, and re-modelling in 1050-1100 AD

Question 5

Optically stimulated luminescence dating
- Quartz grain analysis

Answer 5

For an exposed sediment:
- Exposure to sunlight bleaches sample and ‘open traps’

Buried sediment:
- Natural backgroup radiation fills traps at a constant rate
- Longer the grain is buried, the more radiant energy is built up, the more that would be released in the lab

Laboratory measurement
- Radiation accumulated during burial released as photons by laser excitation
- Traps opened, stored dose measured
- Constant rate of accumulation allows age to be assessed

MUST MEASURE BACKGROUND RADIATION, varies by site

Question 6

Optically Stimulated Luminescence Dating
- Dose rate meaning
- Stored dose meaning

Answer 6

• Dose rate = how rapidly the radiant energy is accumulating
• Stored dose = how much has been accumulated
• Comparison between the two gives an estimation of chronology

Question 7

Kasthamandap Timbers

Answer 7

• Relate dates to the structural material
• Salvaged timbers
• Core the timbers to do radiocarbon dating
• Re-use of timbers, with new ones coming in
• Revealed/may suggest even earlier construction associated with the site: 424-565 AD

Question 8

Kasthamandap dating and chronologies
Preliminary model

Answer 8

• 910 BC: Onset of human activity in the area, agriculture, woodland clearence
• 100 BC - AD 100: Early activity in area - urbanisation - early mandala?
• AD 600-750: First phase Kasthamandap foundations
• AD 800: Second phase foundations - cross walls; timber super-structure remodelling
• AD 1050 (/later-mid 1100’s?): Timber superstructure remodelling

Question 9

Cultural ties with Kasthamandap’s foundation formation

Answer 9

• Historical evidence: building architectures (Indian material)
• “Foundation deposits…its bottom should be covered with every sort of earth: from a river, from a pond, from a wheat field, from a mountain, an anthill”
• “The trench should be filled with bricks, earth, and fine sand, and packed tight to that there are no gaps”

Question 10

Foundations of Kasthamandap - what is important to note?

Answer 10

• The control material at the top is different to the associated construction material: they’re not using local material in these foundations
• Proportion of clays, slits, and sands

Question 11

Evidence of earthquake activity within the Kasthamandap foundations x4

Answer 11

• Dykes and sills
• Bulbous intrusions
• Rip-up clasts
• Clay coatings/infills

Question 12

Contrast between upper and lower mandala

Answer 12

Micro-layering of fine clay ceramics, burnt material, organic inclusions, then capped