Discovery of the palaeo-Indus delta-fan complex
Discovery of the palaeo-Indus delta-fan complex
复制标题
古印度河三角洲扇复合体的发现
DOI：
10.1144/gsjgs.154.5.0753
复制
发表时间：
1997
影响因子：
2.7
通讯作者：
A. Niem
中科院分区：
文献类型：
--
作者：
M. Qayyum;R. D. Lawrence;A. Niem
印度河携带着喜马拉雅西部的沉积物，并将其中一些沉积为河道和河漫滩沉积物或磨拉石。其余的部分形成了印度洋边缘的印度河三角洲。印度河三角洲的一些沉积物通过印度河海底扇浊积岩沉积。因此，喜马拉雅期磨拉石、三角洲和扇沉积与其他地区一样，在时间和空间上是相关的。然而，当我们检查河流和海洋的年龄范围数据的旧印度河沉积物，在这种沉积组合，其海洋记录的主要部分是失踪。已知最古老的磨拉石沿着印度河缝合带和前渊分别为始新世中期和古新世晚期。然而，最近对北方印度洋沉积作用的综合研究表明，浊流沉积作用开始于中新世早期的现代印度河扇，甚至更晚的孟加拉扇。古近纪印度河三角洲和扇沉积物在哪里？我们认为，在Katawaz盆地和东Makran，这些被保存为古近纪硅质岩Khojak组。现代印度河长2900 km（Coumes & Kolla 1984），夏季流量为30 000 m3 s − 1（Milliman et al. 1984）（图1），是密西西比河流量的两倍。年悬浮泥沙量（威尔斯和科尔曼，1984年）在395至435 × 103 t之间变化，几乎等于密西西比河。中始新世至中中新世印度磨拉石沿着
The Indus River carries sediments from the western Himalaya and deposits some of these as channel and floodplain sediments or molasse. The rest of its load forms the Indus delta at the margin of the Indian Ocean. The Indus delta passes some of its sediments to be deposited as Indus submarine fan turbidites. Thus, as elsewhere, Himalayan molasse, delta, and fan deposition are related hi tune and space. However, when we examine fluvial and marine age-range data of the older Indus deposits, in terms of this sedimentary assemblage, a major portion of its marine record is missing. The oldest known molasse along the Indus suture zone, and hi the foredeep are middle Eocene and late Palaeocene hi age, respectively. A recent synthesis of sedimentation in the northern Indian Ocean, however, shows that turbidite sedimentation started around early Miocene in the modern Indus fan, and even later in the Bengal fan. Where are the Palaeogene Indus delta and fan sediments? We suggest herein that these are preserved as the Palaeogene siliciclastic Khojak Formation hi the Katawaz Basin and eastern Makran. The modern Indus River is 2900 km long (Coumes & Kolla 1984) and has 30 000 m3 s − 1 discharge (Milliman et al. 1984) in summer (Fig. 1), twice that of the Mississippi River. The annual suspended sediment load (Wells & Coleman 1984) varies between 395 and 435 x 103 t, almost equal to that of the Mississippi. The existence of the middle Eocene to middle Miocene Indus molasse along the