Universität zu Köln

Wittke, Andreas, Gussone, Nikolaus, Derigs, Dominik and Teichert, Barbara M. A. (2022). Evolution of fluid flow and carbonate recrystallization rates in deep-sea sediments of the Equatorial Pacific. Geo-Mar. Lett., 42 (1). NEW YORK: SPRINGER. ISSN 1432-1157

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Abstract

Fluid flow and carbonate recrystallization rates of deep-sea sediments from eight locations in the Equatorial Eastern Pacific were determined by using delta Ca-44/40 values of pore water and corresponding sediments. The studied drill sites of IODP Exp. 320/321 are located along a transect of decreasing crustal age and reveal different characteristic pore water depth profiles. The younger sites show an overall isotopic equilibration with the sediment in the upper part of the sedimentary column. In the lower part, the delta Ca-44/40 of the pore water increases back to seawater-like values at the sediment/basalt interface, forming a bulge-shaped pore water profile. The magnitude of the delta Ca-44/40 pore water bulge decreases with increasing age of the oceanic crust and sediment cover, resulting in seawater-like delta Ca-44/40 values throughout the sedimentary column in the oldest Sites U1331 and U1332. These findings indicate a seawater-like fluid input from the underlying crust into the sediment. Thus, after sedimentation, carbonate recrystallization processes start to enrich the pore water in Ca-40, and after a time of carbonate recrystallization and cooling of oceanic crust, a flow of seawater-like fluid starts to move upwards through the sedimentary column, enriching the pore water with Ca-44. We established a carbonate recrystallization and fluid flow model to quantify these processes. Our determined carbonate recrystallization rates between 0.000013e((-t/15.5)) and 0.00038e((-t/100.5)) and fluid flow rates in the range of 0.42-19 m*Myr(-1) indicate that the fluid flow within the investigated sites of IODP Exp. 320/321 depends on the sedimentary composition and location of the specific site, especially the proximity to a recharge or discharge site of a hydrothermal convection cell.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Wittke, Andreas UNSPECIFIED UNSPECIFIED UNSPECIFIED Gussone, Nikolaus UNSPECIFIED UNSPECIFIED UNSPECIFIED Derigs, Dominik UNSPECIFIED UNSPECIFIED UNSPECIFIED Teichert, Barbara M. A. UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-673044
DOI:	10.1007/s00367-021-00720-9
Journal or Publication Title:	Geo-Mar. Lett.
Volume:	42
Number:	1
Date:	2022
Publisher:	SPRINGER
Place of Publication:	NEW YORK
ISSN:	1432-1157
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language CALCIUM ISOTOPE FRACTIONATION; EARLY MARINE DIAGENESIS; PORE FLUID; SR; SEAWATER; DELTA-CA-44; SEAMOUNTS; CHEMISTRY; HEAT; DISSOLUTION Multiple languages Geosciences, Multidisciplinary; Oceanography Multiple languages
URI:	http://kups.ub.uni-koeln.de/id/eprint/67304