THE GUANGALA AND

MANTEÑO-HUANCAVILCA

SHELL ORNAMENT

PRODUCTION METHODS

Sydney Cargill, Isha Chavva, Shannon Duffy, Julia Flores, Jennifer Mao, Gabrielle Shvartsman, Cindy

Weng, Sharmitha Yerneni

Peru

Spondylus

Guangala 200 B.C.- 600/800 A.D.

Manteño-Huancavilca 700/900 A.D. - 1530 A.D.

● Samples were recovered from two main sites ○ Site 47 near El Azúcar

(Guangala) ○ Site T2-2 near Chanduy

(Manteño-Huancavilca)

Hypotheses 1. Shell reduction - combination of sawing and

knapping processes 2. Drilling - comparing Guangala and

Manteño-Huancavilca beads 3. Grinding - added to shell reduction process

during Manteño-Huancavilca

How did they get from a Spondylus shell to a 4 mm bead?

Shell Reduction: Sawing

archaeological samples suggestive of sawing

archaeological

experimental

Boiling and the Moh’s Hardness Scale

Hardness (Moh’s Hardness Scale)

Trial 1 Trial 2 Trial 3

After Boiling 5

min.

After Cooling 5

min.

After Boiling 5

min.

After Cooling 5

min.

After Boiling 5

min.

After Cooling 5

min.

2 3 3 3-4 3 3

Calcite, Shell, Gypsum Fluorite, Shell, Calcite Fluorite, Shell, Calcite

(Top to Bottom) (Top to Bottom) (Top to Bottom)

Shell Reduction: Knapping

Piece that was knapped off from the cortex

archaeological experimental

Drilling: Bead Perforation Analysis

Scanning Electron Microscopy (SEM)

Comparison of Drilling Methods

Although the drill hole rims of both the Guangala and M-H beads were smooth, the interior

cavity of the M-H bead was smoother than that of the Guangala bead.

Guangala Bead Manteño-Huancavilca Bead

Shell Refinement: Grinding

sandstone

Experimental Shell Sample 1 (circular method)

Experimental Shell Sample 2 (back-and-forth method)

Circular Method

Back-and-Forth Method

Archaeological Shell Sample

Guangala Bead Manteño-Huancavilca Bead Circular Method

Back-and-forth Method Guangala Bead Manteño-Huancavilca Bead

Fracture Method

● Find fracture lines

● Obsidian pieces to cut

● Under five minutes

● No grit, lemon, or boiling

● 1mm deep cut

● considerably efficient

● Compared ridges:

experimental and original

● pre-existing vs. created

fractures

● Fracture creation risky

● More research

Experimental Original

Future Research

Conclusion

Acknowledgements We would like to thank:

Independent College Fund of NJ/Johnson & Johnson AT&T

Bayer Healthcare The Overdeck Family Foundation

NJGSS Alumnae, Parents, and Corporate Matching Funds Board of Overseers, New Jersey Governor’s Schools

The State of New Jersey Drew University

Dr. Maria Masucci Dr. Adam Cassano Dr. Steve Surace

Kaushaly (Shelly) Patel Yumi Kouh

References Spondylus shell and beads:

http://news.nationalgeographic.com/news/2013/12/131203-chimu-

tomb-ancient-peru-nobles-sacrifices-archaeology-science/

Red Spondylus necklace:

http://nga.gov.au/exhibition/Incas/Default.cfm?IRN=231264&BioArtistIR

N=91411&MnuID=3&GalID=3&ViewID=2

Moh’s hardness scale:

http://www.nature.nps.gov/geology/education/concepts/minerals.cfm

SEM picture

http://ares.jsc.nasa.gov/Laboratories/kr_laboratories/SEM.cfm

THANK YOU!