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Magnetic record associated with tree ring density: possible climate proxy.

Kletetschka G, Pruner P, Venhodova D, Kadlec J - Geochem. Trans. (2007)

Bottom Line: A magnetic signature of tree rings was tested as a potential paleo-climatic indicator.Such a record suggests that the European LIA was a global phenomenon.Magnetic analysis of the thermal stability reveals the blocking temperatures near 200 degree C.

View Article: PubMed Central - HTML - PubMed

Affiliation: Institute of Geology, AS CR, Prague, 16502, Czech Republic. kletetschka@nasa.gov

ABSTRACT
A magnetic signature of tree rings was tested as a potential paleo-climatic indicator. We examined wood from sequoia tree, located in Mountain Home State Forest, California, whose tree ring record spans over the period 600 - 1700 A.D. We measured low and high-field magnetic susceptibility, the natural remanent magnetization (NRM), saturation isothermal remanent magnetization (SIRM), and stability against thermal and alternating field (AF) demagnetization. Magnetic investigation of the 200 mm long sequoia material suggests that magnetic efficiency of natural remanence may be a sensitive paleoclimate indicator because it is substantially higher (in average >1%) during the Medieval Warm Epoch (700-1300 A.D.) than during the Little Ice Age (1300-1850 A.D.) where it is <1%. Diamagnetic behavior has been noted to be prevalent in regions with higher tree ring density. The mineralogical nature of the remanence carrier was not directly detected but maghemite is suggested due to low coercivity and absence of Verwey transition. Tree ring density, along with the wood's magnetic remanence efficiency, records the Little Ice Age (LIA) well documented in Europe. Such a record suggests that the European LIA was a global phenomenon. Magnetic analysis of the thermal stability reveals the blocking temperatures near 200 degree C. This phenomenon suggests that the remanent component in this tree may be thermal in origin and was controlled by local thermal condition.

No MeSH data available.


Related in: MedlinePlus

The magnetic remanence is shown as function of temperature during a cryogenic warming (SIRM given at 20 K) and subsequent cryogenic cooling (SIRM given at 300 K). The signal to noise ratio was 3/1. The data are approximated with Stineman function. The output of this function then has a geometric weight applied to the current point and ± 10% of the data range, to arrive at the smoothed curve. Data were taken at MPMS, Institute for Rock Magnetism, Minnesota.
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Figure 3: The magnetic remanence is shown as function of temperature during a cryogenic warming (SIRM given at 20 K) and subsequent cryogenic cooling (SIRM given at 300 K). The signal to noise ratio was 3/1. The data are approximated with Stineman function. The output of this function then has a geometric weight applied to the current point and ± 10% of the data range, to arrive at the smoothed curve. Data were taken at MPMS, Institute for Rock Magnetism, Minnesota.

Mentions: Low temperature magnetic data were obtained at the Institute for Rock Magnetism, University of Minnesota. Small sample (5 mm × 5 mm × 10 mm) from the section near 650 years was cut, using a knife, to fit inside the plastic straw, the holder for Quantum Design MPMS cryogenic magnetometer. The sample was brought to 20 K, acquired saturation remanence in field of 5T and warmed up to 300 K. At 300 K the sample was again given saturation remanence and brought back to 20 K (see Figure 3).


Magnetic record associated with tree ring density: possible climate proxy.

Kletetschka G, Pruner P, Venhodova D, Kadlec J - Geochem. Trans. (2007)

The magnetic remanence is shown as function of temperature during a cryogenic warming (SIRM given at 20 K) and subsequent cryogenic cooling (SIRM given at 300 K). The signal to noise ratio was 3/1. The data are approximated with Stineman function. The output of this function then has a geometric weight applied to the current point and ± 10% of the data range, to arrive at the smoothed curve. Data were taken at MPMS, Institute for Rock Magnetism, Minnesota.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC1851700&req=5

Figure 3: The magnetic remanence is shown as function of temperature during a cryogenic warming (SIRM given at 20 K) and subsequent cryogenic cooling (SIRM given at 300 K). The signal to noise ratio was 3/1. The data are approximated with Stineman function. The output of this function then has a geometric weight applied to the current point and ± 10% of the data range, to arrive at the smoothed curve. Data were taken at MPMS, Institute for Rock Magnetism, Minnesota.
Mentions: Low temperature magnetic data were obtained at the Institute for Rock Magnetism, University of Minnesota. Small sample (5 mm × 5 mm × 10 mm) from the section near 650 years was cut, using a knife, to fit inside the plastic straw, the holder for Quantum Design MPMS cryogenic magnetometer. The sample was brought to 20 K, acquired saturation remanence in field of 5T and warmed up to 300 K. At 300 K the sample was again given saturation remanence and brought back to 20 K (see Figure 3).

Bottom Line: A magnetic signature of tree rings was tested as a potential paleo-climatic indicator.Such a record suggests that the European LIA was a global phenomenon.Magnetic analysis of the thermal stability reveals the blocking temperatures near 200 degree C.

View Article: PubMed Central - HTML - PubMed

Affiliation: Institute of Geology, AS CR, Prague, 16502, Czech Republic. kletetschka@nasa.gov

ABSTRACT
A magnetic signature of tree rings was tested as a potential paleo-climatic indicator. We examined wood from sequoia tree, located in Mountain Home State Forest, California, whose tree ring record spans over the period 600 - 1700 A.D. We measured low and high-field magnetic susceptibility, the natural remanent magnetization (NRM), saturation isothermal remanent magnetization (SIRM), and stability against thermal and alternating field (AF) demagnetization. Magnetic investigation of the 200 mm long sequoia material suggests that magnetic efficiency of natural remanence may be a sensitive paleoclimate indicator because it is substantially higher (in average >1%) during the Medieval Warm Epoch (700-1300 A.D.) than during the Little Ice Age (1300-1850 A.D.) where it is <1%. Diamagnetic behavior has been noted to be prevalent in regions with higher tree ring density. The mineralogical nature of the remanence carrier was not directly detected but maghemite is suggested due to low coercivity and absence of Verwey transition. Tree ring density, along with the wood's magnetic remanence efficiency, records the Little Ice Age (LIA) well documented in Europe. Such a record suggests that the European LIA was a global phenomenon. Magnetic analysis of the thermal stability reveals the blocking temperatures near 200 degree C. This phenomenon suggests that the remanent component in this tree may be thermal in origin and was controlled by local thermal condition.

No MeSH data available.


Related in: MedlinePlus