The nature of "channel elements" as building blocks of submarine channel fill

JUAN PABLO MILANA

San Juan

Simposio; Slopes Consortium Final Meeting; 2012

University of Aberdeen

The conclusions of this work are the following: CONCLUSIONS 1. In any Channel complex set, there will be more ?channel elements? near base and more sheet-like bedsets towards top 2. Good correlation between "high angle" crossbeds and rolling type fabric supports subcritical flow dune stage).Variable correlation between fabric and sheet-like bedding suggests deposition from sub and supercritical flows 3. Suspensive fabric suggest supercritical flow (antidune-standing waves). Complete preservation only occurs under high fallout events (base gradational) while low-fallout events cause erosive base. 4. Dominant rolling type fabric at the upper parts of channel elements suggest reworking and/or deposition by lower energy, tractive flows, without the necessary depth of flow to generate gavel waves. A proof is the presence of oversized clasts (huge blocks surrounded by tractive dominated gravel). 5. Single channels (Playa Esqueleto) show dominant rolling type fabric (no crossbeding). Flows are interpreted as not very thick and less energetic than at Channel assemblages 6. All samples suggest a well developed traction carpet with different concentration (not debris flows). This would apply to 97% of conglomerates in San Fernando submarine channel system 7. Many small CHANNEL ELEMENTS could be actually isolated SCOURS related to the front of migrating DUNES.