Model of alluvial fan development based on channel pattern and gravel size

作者在捷克和斯洛伐克发现了一些冲积扇，它们具有冲积扇上的自由曲流阶段、切割曲流阶段和阶地陡坡发育阶段，如波兰冲积扇（Saito, 2002a）。为了证实扇的这一过程，作者不仅收集了地貌学研究的资料，还收集了沉积学研究的资料。因此，冲积扇的定义似乎是沉积学研究中的一个重要问题。因此，详细解释了这个问题（Saito, 2001a），并翻译了Blair和McPherson（1994）的论文（Saito, 2001b）。特别是Blair和McPherson（1994）认为，自然界不存在0.5°~ 1.5°的沉积斜坡，但日本超过2km^2的冲积扇的平均斜坡上不存在间隙。此外，作者还列出了冲积扇区域的研究领域和关键词（2002b）。因此，确定缓坡冲积扇和陡坡冲积扇的判别标准以及冲积扇最低坡度置信度（可能为1‰）具有重要意义。前扇由河流沉积组成，后扇由泥石流组成。

In Czech and Slovak the author found some alluvial fans which have a free meander stage on an alluvial fan, an incised meander stage, and development stage of terrace scarp by a straight channel like Polish alluvial fans (Saito, 2002a). Confirming such processes of the fans, the author collected references not only on geomorphological studies but also on sedimentological studies. Hence, the definition of an alluvial fan seems to be serious problem on sedimentological studies. Consequentlty, the problem was explained in detail (Saito, 2001a) and the paper of Blair and McPherson (1994) was translated (Saito, 2001b). In particular, Blair and McPherson (1994) asserted that there are no depositional slopes ranging from 0.5° to 1.5° in nature, but no gap exist on the mean slopes of alluvial fans with over 2km^2 in Japan. Moreover, the author made a list of research areas and keywords on regions of alluvial fans (2002b). In consequent, it is important to get the criteria of a gentle-slope alluvial fan and a steep-slope one and the confidence of the lowest gradient of alluvial fan, probably 1 ‰. Besides, former fan consists of fluvial deposits, while latter one is made of debris flow.