부산대학교 도서관

Since their uplift and emergence in the Miocene, the predominantly limestone horst massifs of Crete have been incised by steepland rivers, but Quaternary climate changes have also resulted in alluvial cut-and-fill sequences within the valleys. Distinctive wave-cut notches up to 9 m above present mean sea level around southwestern Crete have been dated, and uplift ascribed to the documented earthquake of AD 365. Ground surveys, geomorphological mapping, sedimentological investigations, and geochronology (OSL, radiocarbon, uraniumseries, and dendrochronology) have enabled detailed reconstruction of the timing and pattern of sedimentation and erosion over the late Holocene. Following uplift, the dominantly-bedrock rivers incised into their uplifted and exposed cemented fan deltas, initiating knickpoint propagation. Given the limited sediment supply to these systems, subsequent climate changes have had little discernible influence on their morphology and sedimentology. In contrast, following uplift, the dominantly-alluvial rivers rapidly incised through their alluviated lower reaches, with knickpoints propagating into bedrock-controlled reaches upstream. Coupled with higher sediment supply, subsequent cut and fill processes have left complex but decipherable terrace records in the lower reaches. The responses of two alluvial fan rivers diverged following uplift. For the first river, uplift exposed a wave cut platform with a lower gradient than the upstream river, leading to the aggradation of a new fan on the exposed area. The second river appears largely unaffected by base level fall, and is instead incising in response to distal truncation of a large alluvial fan at the river mouth. Aggradation in these systems appear to coincide with regional periods of aridity or increasing aridity, during which rainfall tends to be concentrated into fewer, but more intensive precipitation events. Hence, the nature of the responses since AD 365 has been determined by the interplay of factors that are intrinsic to each system and extrinsic effects that correlate primarily with climatic change.