These dynamics will change with the addition of ‘bottom up’ controls such as main river incision, which will typically enhance the coupling effect of both systems. The alluvial fans act as potential ‘buffers’ between hillslopes and river terrace records under ‘top down’ climate-driven high sediment supply and alluvial fan aggradation, and ‘couplers’ during periods of less sediment (in relation to water) discharge and alluvial fan incision. A simple conceptual model is proposed to summarise the dynamic role of alluvial fans within this landscape context. These are i) continuous mountain front alluvial fans interacting with a non incising but laterally eroding axial fluvial system ii) alluvial fans which transition into fluvial terraces as sedimentary basins shift from net aggradation to net incision and iii) tributary-junction alluvial fans that develop predominantly within incising river valley systems. 3 regional case studies are presented that illustrate the interaction between alluvial fan and river terrace archives at Quaternary time-scales at 3 different stages of landscape evolution. Published literature is used to examine both thematic and geographical based benefits of alluvial fan research that can assist understanding of Quaternary fluvial archives.
#2018 north ba ycal fire archive
This paper examines the dynamic role of alluvial fans within the fluvial landscape and their interaction with river systems, highlighting the potential value of alluvial fans to the wider fluvial archive community. Despite modern sedimentary basins comprising a significant (>88%) volume of distributive fluvial systems, of which alluvial fans (>1 km, <30 km in scale) are a significant part, interaction with these environments tends to be neglected and discussed in separate literature.
The fluvial archive literature is dominated by research on river terraces with appropriate mention of adjacent environments such as lakes. The latter is recommended as the stratigraphical term for the refined subdivision of the uppermost part of late Quaternary sediments in the Miaoli Tableland.
The landforms and predominantly the sediment sequences are discussed in the context of the existing stratigraphical schemes of the Toukoshan Formation and the so far rarely used Lungkang Formation. The Alluvial and Coastal Plains (AL) represent broad valley bottoms (“box-shaped valleys”) in the dendritic drainage systems below 150 m and the coastal plains. The tableland surfaces have been separated into Sedimentary Highlands (SH-I and SH-II) and Sedimentary Terraces (ST) by geometrical properties. The results reveal a tableland surface much more disaggregated than previously mapped, suggesting that individual tableland segments represent remnants of an inferred palaeotopography. The relation of tectonic and erosional processes including the rework of gravels is discussed. Three subtypes of this sequence were identified, with respect to the occurrence of the fluvial deposits. The outcrops revealed complete or incomplete sequences of the general scheme from bottom to top: sandy tidal–coastal units overlain by gravel- and cobble-rich fluvial deposits always with a fine-grained silt-rich top cover layer influenced by aeolian deposits. Sediments are described in 51 outcrops and characterized by grain size composition. The landforms and the fluvial systems in the Miaoli Tableland are investigated by high-resolution terrain analyses based on different datasets. Their mostly flat surfaces are deeply incised by fluvial processes. If this data is unavailable or inaccurate and you own or represent this business, click here for more information on how you may be able to correct it.Elevated Quaternary sedimentary complexes in the western foreland of the central mountain ranges of Taiwan are called tablelands. VIEW ADDITIONAL DATA Select from over 115 networks below to view available data about this business.
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