TIMS U-series dating and stable isotopes of the last interglacial event in Papua New Guinea

Journal Article · Tue Jun 01 00:00:00 EDT 1993 · Geochimica et Cosmochimica Acta; (United States)

DOI:https://doi.org/10.1016/0016-7037(93)90416-T· OSTI ID:6459343

Stein, M; Wasserburg, G J; Chen, J H ^[1]; Aharon, P ^[2]; Zhu, Z R; Chappell, J ^[3]; Bloom, A ^[4]

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1. California Inst. of Technology, Pasadena (United States)
2. Louisiana State Univ., Baton Rouge (United States)
3. Australian National Univ., Canberra (Australia)
4. Cornell Univ., Ithaca, NY (United States)

The extensive flight of uplifted reef terraces which occurs along the Vitiaz strait on the northern flank of the Huon Peninsula in PNG (Papua New Guinea) contains a particularly good record of sea level changes in the last 250 ky. The Huon terraces were the target of an international expedition which took place in July--August 1988. In particular, the authors searched for suitable samples for U-series dating in a reef complex designated as VII, which is correlated with the last interglacial episode and high sea level stand. This complex is composed of a barrier reef (VIIb), a lagoon, and a fringing reef (VIIa). Twelve corals from these terraces and two corals from the older reef complex VIII were selected for analysis. The petrography, oxygen and carbon isotope compositions, and magnesium and strontium concentrations were determined along with the concentrations and isotopic compositions of uranium and thorium. The simplest model for sea level height for terrace VII is a continuous rise between 134 and 118 ky. Alternatively, there may have been two periods of rapid sea level rise. In contrast, in the Bahamas, there is evidence that sea level remained rather constant over the time interval 132 to 120 ky. The absence of ages between 132 and 120 ky in PNG could be the result of changes in the local tectonic uplift rates during that time, or erosion that disrupted the continuous record. In any event, the authors find no basis for accepting a single brief time for the age of the last interglacial and applying this age as a precise chronometer for worldwide correlation, or as a test of climatic models. The older ages reported here precede the Milankovitch solar insolation peak at 128 ky, and the younger ages are [approximately]10 ky after this peak. If the present high-precision data are correct, then it will be necessary to reassess the validity of the Milankovitch theory of climatic changes. 76 refs., 6 figs., 6 tabs.

• OSTI ID: 6459343
• Journal Information: Geochimica et Cosmochimica Acta; (United States), Journal Name: Geochimica et Cosmochimica Acta; (United States) Vol. 57:11; ISSN GCACAK; ISSN 0016-7037
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
540110*
ACTINIDE ISO
ACTINIDE ISOTOPES
ACTINIDE NUCLEI
AGE ESTIMATION
ALKALINE EARTH METALS
ALPHA DECAY RADIOISOTOPES
ASIA
AUSTRALASIA
BAHAMA ISLANDS
CARBON
CLIMATE MODELS
CLIMATIC CHANGE
DEVELOPING COUNTRIES
ELEMENTS
EVEN-EVEN NUCLEI
GEOLOGIC STRUCTURES
HEAVY ION DECAY RADIOISOTOPES
HEAVY NUCLEI
ISLANDS
ISOTOPE DATING
ISOTOPE RATIO
ISOTOPES
LEVELS
MAGNESIUM 28 DECAY RADIOISOTOPES
MATHEMATICAL MODELS
METALS
NEON 24 DECAY RADIOISOTOPES
NEW GUINEA
NONMETALS
NUCLEI
OXYGEN
RADIOISOTOPES
REEFS
SEA LEVEL
SPONTANEOUS FISSION RADIOISOTOPES
STRONTIUM
TESTING
THORIUM 230
THORIUM ISOTOPES
URANIUM 234
URANIUM ISOTOPES
VALIDATION
WEST INDIES
YEARS LIVING RADIOISOTOPES