Understanding the growth processes and geomorphic features of modern submarine fans will aid in the exploitation of potential hydrocarbon resources in deep-water turbidities. Surveys on four fans in the northeast Pacific using the deep-tow instrument package show a wide variety and size range of relief features. At least three types of channels can be recognized; (1) leveed valleys, common on the upper fan; (2) distributary channels that branch from the active valley; and (3) "headless" channels found at the basin slope and fan margin or along the edges of depositional lobes. All the channel types are associated with areas of active sand deposition. An abandoned distributary channel would likely become the site of deposition of pelagic and hemipelagic muds and occasional hin-bedded turbidities. A connection to the main channel may be maintained by

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the sandy filling of the distributary channel. The distributary channels and their associated depositional lobes may serve as collectors and feeders of hydrocarbons to the main channel system.

Isolated depressions ranging from a few tens of meters to more than a kilometer across are seen on all fans that have been studied with the deep tow. On both Monterey and Navy submarine fans, large scour-shaped depressions are observed. In cross sections perpendicular to the fan gradient, these depressions resemble channels. Cores and reflection data show that these features are floored by sand and could be filled by sand or mud. Contrasting the interconnected nature of buried channel systems, the limited extent and continuity of sand-filled and buried depressions would suggest little potential as hydrocarbon reservoirs. Depositional lobes are also common on submarine fans and range in size from small (1 km wide) features associated with distributary channels to large fan lobes occupy ng tens of square kilometers.

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