Publication Type:
Proposal
Source:
(2008)
Abstract:
The Hawaiian Islands have been widely recognized as a natural laboratory for the study of
weathering and biogeochemical processes. The islands are geographically isolated, have only
small variation in bedrock geology, and have relatively low species diversity (Vitousek, 1995).
The propagation of volcanic activity associated with the movement of the Pacific plate over the
Hawaiian mantle plume creates a predictable pattern of surface lava flow ages (Moore and
Clague, 1992). On the major islands surface lava flows range from “zero age” at the active
eruptive site on Kilauea, to 4.1 million years on Kauai. The high topography of the islands
intersects with the prevailing trade wind field to create stable orographic precipitation patterns
and rain shadows. Rainfall varies systematically from several meters per year on the windward
side to values typical of deserts on the leeward side (Giambelluca et al., 1986). On the islands of
Maui and Hawaii, the elevations are high enough to penetrate a regional inversion layer, leading
to dry and cool conditions at high elevation and seasonal snow cover (Giambelluca et al., 1986;
Nullet et al., 1995). For example, within a few tens of kilometers (or less) on Hawaii Island we
can cross from century age flows to several hundred thousand year ages, from tropical forest to
alpine vegetation or to highly arid grasslands, and from > 4 meters MAP (mean annual
precipitation) to 0.2 meters MAP. These attributes make the Hawaiian archipelago ideal for
studying a variety of important Critical Zone processes.
