New method revises dating
of ancient Maui heiaus

Using a new dating technique, a former Hawaii archaeologist has discovered that a prehistoric heiau system on Maui was built far more rapidly than believed, coinciding with rapid sociopolitical change in the chiefdom.

"It looks like they (temples) were all constructed in a fairly tight time period in Kahikinui, from the late 1500s to the early 1600s," said Patrick Kirch, of the University of California-Berkeley anthropology department.

The Hawaii-born scientist, associated with the Bishop Museum from 1975 to 1984, has done extensive archaeological and ethnoecological research in Hawaii and throughout the Pacific.

He has spent 10 years studying archaeological remains and settlement patterns in the ancient Kahikinui district on Haleakala's southeastern slopes, where 30 Hawaiian temple foundations and many other sites are preserved.

Kirch and Warren Sharp, dating expert at the Berkeley Geochronology Center, reported their latest findings in the January issue of Science magazine.

In a telephone interview, Kirch said archaeologists working in Hawaii have long been frustrated by "multiple possible calendar ages" from the usual method of radiocarbon dating of wood charcoal.

Radiocarbon dating established prehistoric Hawaiian occupation of Kahikinui in a range from 1400 to 1800 A.D.

But new dates obtained by Kirch and Sharp with uranium decay thorium indicated the heiau system was built within 60 years, from the late 1500s to the early 1600s.

Uranium thorium had been used to date coral reefs, but no one had attempted to use it on archaeological sites, Kirch said.

He said he and Sharp decided to try it out on the prehistoric temples because pieces of branch coral were incorporated into the walls or had been placed live as offerings on the foundations when constructed.

"The cool thing here is coral is perfect material for uranium thorium dating because it takes up sea water," he said. "We can use the ratio as a dating technique, similar to radiocarbon."

Kirch said they are getting high-precision dates with a plus or minus factor of six or seven years compared with plus or minus 80 to 100 years with radiocarbon dates.

"The temples provide tangible archaeological evidence of the speed with which a fundamental sociopolitical transition occurred in proto-historic (before European contact) Hawaii," Kirch reported.

The dates dovetail with oral traditions and genealogies that indicate two independent chiefdoms were brought under Piilani's control during his reign, from about 1570 to 1600 A.D., Kirch said. Piilani's grandson took over Lanai and probably Kahoolawe in conquests in 1630 A.D.

Hawaiian temples were built on huge platforms and terraces, and "corresponded to a hierarchy of major gods associated with agriculture or war," Kirch said. They served as centers for control over production and surplus food, he reported.

Kirch said the thorium dating method has potential elsewhere in the Pacific where coral was used to build temples and by some fishermen to make fishhooks.

He is continuing work in Kahikinui, a fairly dry leeward area that he said has never been disturbed by modern development. "It is becoming pretty unique in the islands to have an entire area where we can see settlement.

"You can see the entire patterns of how people used the land from the seashore to the mountains," he said. "It's interesting to see how ancient Hawaiians were able to adapt their economy to an area fairly marginal in agriculture production."