Friday, January 04, 2013

Guide to terminology used in paleoclimate studies of the last 150,000 years

“Event”, Stages
Estimated age (Calendar years)
~10 Kyr to Present
Holocene maximum warming (also referred to as “climatic optimum”)
~4.5 to 6 Kyr (Europe) 10 to 6 Kyr (Southern Hemishphere)
Last deglaciation
~18 to 10 Kyr
Termination I
~14 Kyr
Younger drayas
~12.7 to 11.5 Kyr
Antarctic cold reversal
14 to 13 Kyr
Bolling-Allerod warm period
14.5 to 13 Kyr
Last Glacial
~74 to 14 Kyr
LGM (Last Glacial Maximum)
~25 to 18 Kyr
Last interglacial peak
~124 Kyr
Termination II
~130 Kyr
Eemian/MIS Stage 5e
~128 to 118 Kyr
Heinrich events
Peaks of ice-rafted detritus in marine sediments, ~7 to 10 Kyr time scale.
Dansgaard-Oeschger events
Warm-cold oscillations determined from ice cores with duration ~2 to 3 Kyr
Bond Cycles
A quasi-cycle during the last Ice age whose period is equal to the time between successive Heinrich events.
Periods of rapid deglaciations

Thursday, October 11, 2012

Principle sources of paleoclimatic proxies

Studies of past climates must begin with an understanding of the types of proxy data available and the methods used in their analysis. One must be aware of the difficulties associated with each method used and of the assumptions each entails. With such a background, it may then be possible to synthesize different lines of evidence into a comprehensive picture of former climatic fluctuations, and to test hypotheses about the causes of climatic change.
Major types of proxy data available is given below; (Bradley. R.S., 1991)
1.1.     Glaciological (Ice cores):
A.      geochemistry (major ions and isotopes of oxygen and hydrogen)
B.      gas content in air bubbles
C.      trace element and micro particle concentrations
D.      physical properties (e.g., ice fabric)
1.2.     Geological:
A.      Marine (ocean sediment cores)
(i) Biogenic sediments (planktonic and benthic fossils)
(a) Oxygen isotopic composition
(b) Faunal and floral abundance
(c) Morphological variations
(d) Alkenones (from diatoms)
(ii) Inorganic sediments
(a) Terrestrial (Aeolian) dust and ice-rafted debris
(b) Clay mineralogy
B.      Terrestrial
(a) Glacial deposits and features of glacial erosion
(b) Periglacial features
(c) Shorelines (Eustatic and glacio-eustatic features)
(d) Aeolian deposits (loess and sand dunes)
(e) Lacustrine sediments, and erosional features (shorelines)
(f) Pedological features (relict soils)
(g) Speleothems (age and stable isotope composition)
1.3.     Biological:
A.      Tree rings (width, density, stable isotope composition)
B.      Pollen (type, relative abundance, and/or absolute concentration)
C.      Plant macrofossils (age and distribution)
D.      Insects (assemblage characteristics)
E.       Corals (geochemistry)
F.       Diatoms, ostracods, and other biota in lake sediments (assemblages, abundance, and/or geochemistry)
G.     Modern population distribution (refugia and relict populations of plants and animals)
1.4.     Historical
A.      Written records of environmental indicators (para-meteorological phenomena)
B.      Phenological records


1.  Bradley, R.S. and Eddy, J.A. (1991). Records of past global changes. In: Global Changes of the Past (R.S. Bradley, ed.). Boulder: University Corporation for Atmospheric Research, pg. 5-9.

Saturday, August 04, 2012

Incredible Indonesia, Flores Island

Beauty of Banda Sea from Flores Island, Indonesia

Panoramic view of Banda Sea, Flores Island, Indonesia

Geological field work

Rest in shadow

Huge tender coconut for drinking and relaxation 

Small beach in Flores Island, Indonesia

Thrilling journey in search of minerals

Shy girl