Experiments on combined-flow bed forms and stratification
- Massachusetts Institute of Technology, Cambridge, MA (USA)
Experiments on equilibrium bed configurations in fine sands under combined flows have been made in a large oscillatory-flow water tunnel. The oscillatory-flow component had oscillation periods of 8-10 sec and maximum oscillatory flow velocities of up to almost 1 m/sec; the unidirectional flow component ranged from zero to about 0.25 m/sec. The bed configuration varies widely in scale and geometry as a function of flow conditions. At combinations of relatively low unidirectional and oscillatory velocities, ripples become larger (over 1 m in spacing) but without a sharp break in size with increasing velocity. There is a striking increase in the degree of asymmetry of the bed forms with increasing unidirectional velocity; a unidirectional velocity of only 0.05-0.10 m/sec produces strong asymmetry of the ripples. Exploratory work on stratification styles produced by the existence of relatively large ripples at combinations of high oscillatory velocities and nonnegligible unidirectional velocities during slow net aggradation of the bed show a characteristic hummocky-swaly geometry of cross-stratification with noticeable asymmetry of dip directions.
- OSTI ID:
- 6642592
- Report Number(s):
- CONF-900605-; CODEN: AABUD
- Journal Information:
- AAPG Bulletin (American Association of Petroleum Geologists); (USA), Vol. 74:5; Conference: Annual convention and exposition of the American Association of Petroleum Geologists, San Francisco, CA (USA), 3-6 Jun 1990; ISSN 0149-1423
- Country of Publication:
- United States
- Language:
- English
Similar Records
Shelf sandstones and hummocky cross-stratification: New insights on a stormy debate
Antidune behavior and stratification