Composition and timing of carbonate vein precipitation within the igneous basement of the Early Cretaceous Shatsky Rise, NW Pacific

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doi: 10.1016/j.margeo.2014.09.046
Author(s): Li Sanzhong; Geldmacher, Jörg; Hauff, Folkmar; Garbe-Schönberg, Dieter; Yu Shan; Zhao Shujuan; Rausch, Svenja
Author Affiliation(s): Primary:
Ocean University of China, College of Marine Geosciences, Qingdao, China
Other:
Leibniz Institute for Marine Sciences, Germany
Christian-Albrechts University of Kiel, Germany
University of Bremen, Germany
Volume Title: Marine Geology
Source: Marine Geology, Vol.357, p.321-333. Publisher: Elsevier, Amsterdam, Netherlands. ISSN: 0025-3227 CODEN: MAGEA6
Note: In English. 58 refs.; illus., incl. 1 table, sketch map
Summary: Numerous calcium carbonate veins were recovered from the igneous basement of the Early Cretaceous Shatsky Rise during Integrated Ocean Drilling Program (IODP) Expedition 324. The chemical (Sr/Ca, Mg/Ca) and isotopic (87Sr/86Sr, 143Nd/144Nd, δ18O, δ13C) compositions of these veins were determined to constrain the timing of vein formation. A dominant control by seawater chemistry on calcite composition is evident for most vein samples with variable contributions from the basaltic basement. Slightly elevated precipitation temperatures (as inferred from oxygen isotope ratios), indicative of hydrothermal vein formation, are only observed at Site U1350 in the central part of Shatsky Rise. The highest 87Sr/86Sr ratios (least basement influence) of vein samples at each drill site range from 0.70726 to 0.70755 and are believed to reflect the contemporaneous seawater composition during the time of calcite precipitation. In principle, age information can be deduced by correlating these ratios with the global seawater Sr isotope evolution. Since the Sr isotopic composition of seawater has fluctuated three times between the early and mid Cretaceous, no unambiguous precipitation ages can be constrained by this method and vein precipitation could have occurred at any time between ∼ 80 and 140 Ma. However, based on combined chemical and isotopic data and correlations of vein composition with formation depth and inferred temperature, we argue for a rather early precipitation of the veins shortly after basement formation at each respective drill site. Abstract Copyright (2014) Elsevier, B.V.
Year of Publication: 2014
Research Program: IODP Integrated Ocean Drilling Program
Key Words: 02 Geochemistry; 12 Stratigraphy, Historical Geology and Paleoecology; Alkaline earth metals; Basement; Calcite; Calcium; Calcium carbonate; Carbonates; Cretaceous; Expedition 324; Genesis; Geochemistry; IODP Site U1346; IODP Site U1347; IODP Site U1349; IODP Site U1350; Igneous rocks; Integrated Ocean Drilling Program; Isotope ratios; Isotopes; Lower Cretaceous; Magnesium; Mesozoic; Metals; Mg/Ca; Nd-144/Nd-143; Neodymium; North Pacific; Northwest Pacific; O-18/O-16; Oxygen; Pacific Ocean; Paleo-oceanography; Precipitation; Rare earths; Sea water; Shatsky Rise; Sr-87/Sr-86; Sr/Ca; Stable isotopes; Strontium; Trace elements; Veins; West Pacific
Coordinates: N380024 N380024 E1623843 E1623843
N323029 N323029 E1591405 E1591405
N360657 N360657 E1582730 E1582730
N360429 N360429 E1591704 E1591704
Record ID: 2015023692
Copyright Information: GeoRef, Copyright 2017 American Geosciences Institute. Reference includes data from CAPCAS, Elsevier Scientific Publishers, Amsterdam, Netherlands