Near-Bed Structure of Sediment Gravity Flows Measured by Motion-Sensing "Boulder-Like" Benthic Event Detectors (BEDs) in Monterey Canyon

Gwiazda, R.1; Paull, C. K.1; Kieft, B.1; Klimov, D.1; Herlien, R.1; Lundsten, E.1; McCann, M.1; Cartigny, Matthieu J.2; Hamilton, A.1; Xu, J.3; Maier, Katherine L.4,5; Parsons, D. R.6; Talling, Peter J.7

2022-02-01

10.1029/2021JF006437

JOURNAL OF GEOPHYSICAL RESEARCH-EARTH SURFACE   影响因子和分区

2169-9003

2169-9011

The near-bed section of submarine gravity flows travels at the highest and most destructive speeds making direct measurements of this region of the flow difficult. Here results are presented from "boulder-like" Benthic Event Detectors (BEDs) that measured their own rotation, depth and temperature while carried within the near-bed region of gravity flows. BEDs were deployed in Monterey Canyon from 200 to 500 m water depth for 18 months (2016-2017) during the Coordinated Canyon Experiment. BEDs moved in 10 out of 14 gravity flows that transited the upper canyon. BEDs moved within the body of the flow because the initial velocities of the BEDs were 66 +/- 16% (1 SD) of the flow transit velocities. BEDs rotated freely during most of their first moves and gained depth faster than in later moves, when their motion was more random and wobblier. The differences in BED motions between first and later moves suggest BEDs moved at different depths within the flow. The inferred near-bed flow structure is strongly stratified with a fast, less-dense layer moving above a slower and denser layer. Coherent changes between pressure and acceleration indicate that BEDs rode a crescent shaped bedform (CSB) morphology that persisted throughout flow events. The variability in BED speeds while riding the CSB morphology indicates a fluid-like nature of the near-bed layer. BED motions ended after being caught in the trough of a CSB. Based on recorded temperature decay rates after flow events, the thickness of redeposited sediment is 2-3 m.

sediment gravity flow basal layer turbidite crescent-shaped bedform Benthic Event Detector (BED) Monterey Canyon

SCI

英语

其他

Natural Environment Research Council["NE/K011480/1","NE/L013142/1"] ; EU Horizon 2020 Programme (GEOSTICK)[725955]

Geology

Geosciences, Multidisciplinary

WOS:000763469400001

AMER GEOPHYSICAL UNION

GEOSCIENCES

Web of Science

1.Monterey Bay Aquarium Res Inst, Moss Landing, CA 95039 USA
2.Univ Durham, Geog Dept, Durham, England
3.Southern Univ Sci & Technol, Dept Ocean Sci & Engn, Shenzhen, Peoples R China
4.US Geol Survey, Pacific Coastal & Marine Sci Ctr, Santa Cruz, CA USA
5.Natl Inst Water & Atmospher Res, Wellington, New Zealand
6.Univ Hull, Energy & Environm Inst, Kingston Upon Hull, N Humberside, England
7.Univ Durham, Dept Earth Sci, Durham, England

Gwiazda, R.,Paull, C. K.,Kieft, B.,et al. Near-Bed Structure of Sediment Gravity Flows Measured by Motion-Sensing "Boulder-Like" Benthic Event Detectors (BEDs) in Monterey Canyon[J]. JOURNAL OF GEOPHYSICAL RESEARCH-EARTH SURFACE,2022,127(2).

Gwiazda, R..,Paull, C. K..,Kieft, B..,Klimov, D..,Herlien, R..,...&Talling, Peter J..(2022).Near-Bed Structure of Sediment Gravity Flows Measured by Motion-Sensing "Boulder-Like" Benthic Event Detectors (BEDs) in Monterey Canyon.JOURNAL OF GEOPHYSICAL RESEARCH-EARTH SURFACE,127(2).

Gwiazda, R.,et al."Near-Bed Structure of Sediment Gravity Flows Measured by Motion-Sensing "Boulder-Like" Benthic Event Detectors (BEDs) in Monterey Canyon".JOURNAL OF GEOPHYSICAL RESEARCH-EARTH SURFACE 127.2(2022).