ALBERT — All Library Books, journals and Electronic Records Telegrafenberg

1

Series available for loan

Report and preliminary results of Sonne Cruise SO175, Miami-Bremerhaven, 12.11-30.12.2003 (2004)

Kopf, Achim ; Bannert, Bernhard ; Brückmann, Warner

Bremen : Fachbereich Geowiss., Univ.

Associated volumes

add to mindlist on the mindlist

Details Availability

Call number: ZSP-166(228)

In: Berichte aus dem MARUM und dem Fachbereich Geowissenschaften der Universität Bremen

Type of Medium: Series available for loan

Pages: 218 S.

Series Statement: Berichte aus dem Fachbereich Geowissenschaften der Universität Bremen 228

Classification:

Oceanology

Location: Lower compact magazine

Branch Library: GFZ Library

Permalink

	Location	Call Number	Expected	Availability

Others were also interested in ...

BOOK

Link to Library Catalog

S·F·X

2

Unknown

Structural synthesis: correlation of structural fabrics, velocity anisotropy, and magnetic susceptibility data (1993)

Byrne, Timothy ; Brückmann, Warner ; Owens, William ; [et al.]

In: Proceedings of the Ocean Drilling Program: Scientific Results, 131 . pp. 365-378.

add to mindlist on the mindlist

Details

Publication Date: 2016-10-25

Description: Structural, physical property, and magnetic data from Ocean Drilling Program Site 808 in the Nankai Trough, Japan, indicate that both sediment loading and plate convergence have driven dewatering and consolidation in this region. Evidence for this interpretation is provided by a migrated seismic reflection profile, computed tomography of core-scale structures, magnetic susceptibility and P-wave velocity data, and experimental studies of Site 808 samples. These data also show that the strain (including volume change) resulting from plate convergence is partitioned into both penetrative deformation structures as well as more discrete, core-scale structures with finite displacements. These core-scale structures range from relatively subtle, kink-like deflections of the primary phyllosilicate fabric to sharp discontinuities with probable displacements much greater than the dimensions of the core barrel. Although all of the structures acted at least in part as dewatering conduits, evidence of concentrated fluid flow in this region of the prism is limited to a narrow interval almost 150 m above the décollement (located at between 946 and 965 mbsf). This interval correlates with the middle of a hemipelagic sequence above the décollement that appears to have thinned, apparently through dewatering, relative to a more seaward section. Thinning and dewatering appear to have been induced by deposition of a more clastic sedimentary sequence (the outer marginal trench-wedge sediments) that grades upward into a coarse-grained trench-fill sequence. Importantly, the hemipelagic sequence below the décollement appears to have thinned very little, suggesting that these sediments are underconsolidated and overpressured. This interpretation is consistent with porosity measurements from below the décollement. Microscopic and submicroscopic studies of sediments from within the décollement record a cyclic deformation sequence of displacement-brecciation-porosity collapse and compaction that may also reflect deformation of an overpressured sequence. Finally, the structural, physical property, and magnetic data also yield kinematic and geometric results consistent with the present convergent vector between the Philippine Sea Plate and Eurasia. These data indicate a shortening direction that trends between 308° and 315°, consistent with plate convergent vectors that trend between 310° and 314°.

Type: Article , NonPeerReviewed

Format: text

Permalink

	Location	Call Number	Expected	Availability

Others were also interested in ...

PAPER (OCEANREP)

S·F·X

PDF

Fulltext

3

Unknown

In-situ stress conditions at Nankai Trough, Site 808 (1993)

Moran, K. ; Brückmann, Warner ; Feeser, Volker ; [et al.]

In: Proceedings of the Ocean Drilling Program: Scientific Results, 131 . pp. 283-291.

add to mindlist on the mindlist

Details

Publication Date: 2016-03-01

Description: Shipboard laboratory index property data, shore-based consolidation tests, and in-situ stress and pore-pressure measurements are used in this study to constrain the stress conditions at ODP Site 808, Nankai Trough. Results of these tests are presented along with additional intepretations of porosity rebound and permeability. The sediment at Site 808 is highly affected by excess fluid pressures throughout the sediment column. Excess fluid pressure is severe below the major fault boundary, the decollement. The in-situ measurement of lateral stresses, which are shallow in the sediment section, confirms that the principal stress direction is rotated from a "normal" basin-type condition where the principal stress direction is vertical.

Type: Article , NonPeerReviewed

Format: text

Permalink

	Location	Call Number	Expected	Availability

Others were also interested in ...

PAPER (OCEANREP)

S·F·X

PDF

Fulltext

4

Unknown

Stress-regime-controlled yield and strength behavior of sediment from the frontal part of the Nankai accretionary prism (1993)

Feeser, Volker ; Moran, K. ; Brückmann, Warner

In: Proceedings of the Ocean Drilling Program: Scientific Results, 131 . pp. 261-273.

add to mindlist on the mindlist

Details

Publication Date: 2016-10-25

Description: Sediments undergoing accretion in trench-forearc systems are subjected to conditions of large lateral thrusting. This stress regime controls the mechanism of faulting as well as the yield and strength properties of the sediment. Understanding them is therefore crucial for the construction of quantitative models of sediment dynamics in convergent margin settings. For this purpose triaxial and oedometer tests were performed on six whole-round core samples recovered from Site 808 from depths between 173 and 705 mbsf. Samples from five depth intervals were subjected to a triaxial test program that was primarily designed to define yield and strength behavior. Test specimens were cut parallel and normal to the core axis. Additional five oedometer tests with similarly prepared specimens were performed on samples from four depth intervals to evaluate the directional state and degree of sediment compaction. Test results show that the degree of sediment compaction is higher than expected from overburden. This overcompaction increases with depth. A well-developed mechanical anisotropy is evident in all samples tested, regardless of their depth and lithology. Values of yield limit, stiffness, and shear strength are up to 40% higher in the horizontal direction compared to the vertical direction. In addition the test data demonstrate that the axis of the volumetric yield loci have rotated into extensional stress field. This verifies that the mechanical state of sediment in the accretionary wedge is controlled by in-situ stress conditions of extensional nature. The coefficients of lateral stress inferred suggest that the extensional stress regime becomes increasingly effective with depth.

Type: Article , NonPeerReviewed

Format: text

Permalink

	Location	Call Number	Expected	Availability

Others were also interested in ...

PAPER (OCEANREP)

S·F·X

PDF

Fulltext

5

Unknown

Acoustic anisotropy and microfabric development in accreted sediment from the Nankai Trough (1993)

Brückmann, Warner ; Moran, K. ; Taylor, E.

In: Proceedings of the Ocean Drilling Program: Scientific Results, 131 . pp. 221-233.

add to mindlist on the mindlist

Details

Publication Date: 2016-10-25

Description: Complete penetration of frontal thrust and décollement of the Nankai Trough accretionary complex in Site 808 during ODP Leg 131 provided a wealth of structural observations and physical property data. In this paper possible mechanisms are discussed that could be responsible for the development of irregular downhole trends in acoustic anisotropy observed in Site 808. After various steps of data reduction and screening, a paleomagnetic reorientation procedure is applied to a selected group of physical property data sets. This facilitates the integration of the observed changes in physical properties with the geotectonic framework at the deformation front of the Nankai Trough accretionary complex. The paleomagnetic database was employed in the reconstruction of directional properties of acoustic velocities of the Lower Shikoku Basin sedimentary sequence, which is divided by a sharply defined décollement into an accreting and a subducting portion. P-wave velocity anisotropies derived from paleomagnetically oriented samples in the upper part of this 420-m-thick hemipelagic sequence show maximum values in the direction parallel and normal to the inferred vector of plate convergence (31O°-315°). No preferred orientation of P-wave velocity anisotropy is found in the subducting part of the sequence. The preferred direction of maximum anisotropy parallel to the convergence vector is also in accordance with the true direction of the observed macro- to mesoscale structural features in Site 808. Microfractures and microcracks forming as stress relief and tensile fractures in cores of semilithified sediment normal and perpendicular to the maximum horizontal stress are discussed as control mechanisms for the development of the observed anisotropy pattern.

Type: Article , NonPeerReviewed

Format: text

Permalink

	Location	Call Number	Expected	Availability

Others were also interested in ...

PAPER (OCEANREP)

S·F·X

PDF

Fulltext

6

Unknown

Data report: logging while drilling data analysis of Leg 171A, a multivariate statistical approach (2000)

Bücker, C. ; Shimeld, J. ; Hunze, S. ; [et al.]

In: Proceedings of the Ocean Drilling Program: Scientific Results, 171A . pp. 1-29.

add to mindlist on the mindlist

Details

Publication Date: 2016-10-25

Description: In the northern Barbados accretionary wedge, several Deep Sea Drilling Project (DSDP) and Ocean Drilling Program (ODP) legs (DSDP Leg 78 and ODP Legs 110, 156, and 171A) targeted the décollement and the seaward extension of the décollement, the proto-décollement. During Leg 171A, the logging while drilling (LWD) technique was used to determine the physical properties variations along a profile across the deformation front. Because of the unstable borehole conditions in accretionary wedges, LWD is the most effective method for the measurements of physical properties in these poorly consolidated sediments. LWD data are acquired just above the drill bit a few minutes after the formation has been drilled, yielding measurements as close to in situ conditions as possible. The large amount of LWD data and the demand for a quick, objective, and reliable evaluation calls for the application of multivariate statistical methods. The multivariate factor analysis is a method of reducing the amount of logging data while giving them a new integrated meaning with no loss of important information, resulting in factor logs that are helpful tools for further interpretation. The cluster analysis of the two or three most significant factors proved to be a useful and objective method to identify and confirm significant logging units. The main objective of the application of multivariate statistical methods in this study is twofold. First, Leg 171A was a stand-alone logging leg, where no cores were retrieved. The factor analysis was used as an objective tool for a classification of the drilled sequences based on their physical and chemical properties. The new factor logs mirror the basic processes behind the measured geophysical properties and make them easier to interpret. Second, in the succeeding cluster analysis, similar geophysical properties are grouped into one cluster, reflecting one logging unit. These objectively defined logging units can be compared to statistical electrofacies, which are helpful in differentiating lithologic characterizations. In particular for LWD measurements, the multivariate statistical methods of factor and cluster analysis are helpful tools for a fast, reliable, and objective definition of logging units, which should be considered for future legs.

Type: Article , NonPeerReviewed

Format: text

Permalink