A high-resolution marine palynological record from the central mainland coast of British Columbia, Canada: Evidence for a mid-late Holocene dry climate interval

Abstract

Abstract Sediments collected in a 12-m long core (VEC02A04) obtained from Frederick Sound in the Seymour–Belize Inlet Complex of British Columbia were deposited between ca. 4540 cal. yr BP and ca. 1090 cal. yr BP in primarily dysoxic conditions. The sediments are characterized by alternating intervals of fine grained massive and laminated units. Laminated sediments consist of light-coloured diatom-rich layers deposited during summer and dark-coloured mineral-rich layers deposited during winter. Laminated sediments are most common in portions of the core deposited between ca. 2840 cal. yr BP and ca. 1820 cal. yr BP, and correspond to a decline in the relative abundance and pollen accumulation rate of Cupressaceae pollen between ca. 3190 cal. yr BP and ca. 2250 cal. yr BP. The preservation of laminated units and decline of Cupressaceae pollen at this time suggest that a drier and possibly cooler climate punctuated otherwise wet and temperate late Holocene conditions in the Seymour–Belize Inlet Complex. We correlate the occurrence of the mid-late Holocene dry climate interval documented in Frederick Sound to dynamics in the relative position and intensity of the Aleutian Low pressure system and suggest that climate change associated with dynamics of this semi-permanent air mass affected primary productivity and vegetation of the Seymour-Belize Inlet Complex.