East Micronesia (7,821 – 6,094 BCE): Early Holocene — Freshwater Lens Growth and Reef–Valley Coupling (No Human Presence)

Geographic & Environmental Context

East Melanesia includes Kiribati (Gilbert Islands), the Marshall Islands (Ralik and Ratak chains), Nauru (uplifted phosphatic limestone island), and Kosrae (high, volcanic island on the eastern Caroline arc).

• Anchors: broad, perched freshwater lenses began forming beneath Gilbert and Marshall atolls; Kosrae consolidated as a high-island hydrological hub.

Climate & Environmental Shifts

• Holocene thermal optimum: stable trades, warm SSTs, reliable rainfall; occasional Kona-like storm systems.

Baseline Ecology

• Atolls: lens-fed wetlands and shallow sabkha pockets formed behind beach ridges; reef flats and passes matured.

• Kosrae: dense cloud forests, uncut valleys, and intact riparian corridors.

Long-Term Significance

These freshwater lenses are the future substrate for sunken taro gardens (taro pits) and village wells; Kosrae’s perennial streams anticipate wet-field taro.