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Magnetic properties of Cenozoic MORB and Cretaceous MORB from DSDP and ODP holes

Authors
Publisher
PANGAEA
Publication Date
Identifiers
DOI: 10.1594/pangaea.711520
Keywords
  • 129-802A
  • 24-238
  • 26-257
  • 27-261
  • 28-267
  • 29-283
  • 34-320B
  • 38-336
  • 49-412A
  • 52-418A
  • 54-427
  • 58-446
  • 61-462
  • 63-469
  • 65-483B
  • 67-495
  • 72-516F
  • 76-534A
  • 78-543A
  • 82-562
  • 82-564
  • A
  • Al
  • A - Lattice Parameter
  • Aluminium
  • Analytical Electron Microscopy (Aem)
  • Antarctic Ocean/Basin
  • Antarctic Ocean/Tasman Sea
  • Ca
  • Calcium
  • Coercivity
  • Curie Temp
  • Curie Temperature
  • Deep Sea Drilling Project
  • Drilling
  • Dsdp
  • Electron Microprobe
  • Fe
  • Glomar Challenger
  • Hc
  • Hcr/Hc
  • Hysteresis
  • Coercivity Of Remanence/Coercivity
  • Hysteresis
  • Mrs/Ms
  • Hysteresis
  • Saturation Magnetization
  • Hysteresis
  • Saturation Remanence
  • Indian Ocean//Basin
  • Indian Ocean//Fracture Zone
  • Indian Ocean//Plain
  • Inten (Nrm) /Mass
  • Intensity X
  • Intensity Z
  • Iron
  • Joides Resolution
  • Label
  • Leg129
  • Leg24
  • Leg26
  • Leg27
  • Leg28
  • Leg29
  • Leg34
  • Leg38
  • Leg49
  • Leg52
  • Leg54
  • Leg58
  • Leg61
  • Leg63
  • Leg65
  • Leg67
  • Leg72
  • Leg76
  • Leg78
  • Leg82
  • Magnesium
  • Manganese
  • Mdf (Nrm)
  • Mg
  • Mn
  • Mrs
  • Mrs/Ms
  • Ms
  • Nobs
  • North Atlantic/Basin
  • North Atlantic/Cont Rise
  • North Atlantic/Fracture Zone
  • North Atlantic/Norwegian Sea
  • North Atlantic/Ridge
  • North Pacific/Escarpment
  • North Pacific/Gulf Of California/Cont Rise
  • North Pacific/Philippine Sea/Basin
  • North Pacific/Trench
  • North Pacific/Trough
  • North Pacific Ocean
  • Nrm
  • Intensity Per Unit Mass
  • Nrm
  • Median Destructive Field Of Natural Remanent Magnetisation
  • Alternating Field
  • Number Of Observations
  • O2
  • Ocean Drilling Program
  • Odp
  • Odp Sample Designation
  • Oxygen
  • Gas
  • Sample Code/Label
  • Si
  • Silicon
  • South Atlantic/Cont Rise
  • South Pacific/Basin
  • Sum
  • Ti
  • Titanium
  • Transmission Electron Microscope (Tem)
  • V
  • Vanadium
  • Vibrating Sample Magnetometer (Microvsm)
Disciplines
  • Chemistry
  • Earth Science

Abstract

The fact that the natural remanent magnetization (NRM) intensity of mid-oceanic-ridge basalt (MORB) samples shows systematic variations as a function of age has long been recognized: maximum as well as average intensities are generally high for very young samples, falling off rather rapidly to less than half the recent values in samples between 10 and 30 Ma, whereupon they slowly rise in the early Tertiary and Cretaceous to values that approach those of the very young samples. NRM intensities measured in this study follow the same trends as those observed in previous publications. In this study, we take a statistical approach and examine whether this pattern can be explained by variations in one or more of all previously proposed mechanisms: chemical composition of the magnetic minerals, abundance of these magnetization carriers, vectorial superposition of parallel or antiparallel components of magnetization, magnetic grain or domain size patterns, low-temperature oxidation to titanomaghemite, or geomagnetic field behavior. We find that the samples do not show any compositional, petrological, rock-magnetic, or paleomagnetic patterns that can explain the trends. Geomagnetic field intensity is the only effect that cannot be directly tested on the same samples, but it shows a similar pattern as our measured NRM intensities. We therefore conclude that the geomagnetic field strength was, on-average, significantly greater during the Cretaceous than during the Oligocene and Miocene.

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