Magnetic properties of maar lake sediments from Otago, New Zealand
Fuente:
PANGAEA
Gespeichert in:
| Hauptverfasser: | , , , , , |
|---|---|
| Format: | Dataset Open Access |
| Sprache: | en |
| Veröffentlicht: |
PANGAEA
2014
|
| Schlagworte: | |
| Online-Zugang: | |
| Tags: |
Tag hinzufügen
Keine Tags, Fügen Sie den ersten Tag hinzu!
|
| _version_ | 1867169511546814464 |
|---|---|
| author | Fox, Bethany R Storrs Wartho, Jo-Anne Wilson, Gary S Lee, Daphne E Nelson, Faye E Kaulfuss, Uwe |
| author_facet | Fox, Bethany R Storrs Wartho, Jo-Anne Wilson, Gary S Lee, Daphne E Nelson, Faye E Kaulfuss, Uwe |
| collection | Datos científicos de ciencias marinas y ambientales |
| contents | Foulden Maar is a highly resolved maar lake deposit from the South Island of New Zealand comprising laminated diatomite punctuated by numerous diatomaceous turbidites. Basaltic clasts found in debris flow deposits at the base of the cored sedimentary sequence yielded two new 40Ar/39Ar dates of 24.51±0.24 Ma and 23.38±0.24 Ma (2sigma). The younger date agrees within error with a previously published 40Ar/39Ar date of 23.17±0.19 Ma from a basaltic dyke adjacent to the maar crater. The diatomite is inferred to have been deposited over several tens of thousands of years in the latest Oligocene/earliest Miocene, and may have overlapped with the period of rapid glaciation and subsequent deglaciation of Antarctica known as the Mi-1 event. Sediment magnetic properties and SEM measurements indicate that the magnetic signal is dominated by pseudo-single domain pyrrhotite. The most likely source of detrital pyrrhotite is schist country rock fragments from the inferred tephra ring created by the phreatomagmatic eruption that formed the maar. Variations in magnetic concentration and lamina thickness indicate a decrease in erosional input and increase in diatom productivity throughout the depositional period, suggesting a long-term (tens of thousands of years) climatic change in New Zealand in the latest Oligocene/earliest Miocene. |
| format | Dataset Open Access |
| id | pangaea_https___doi_org_10_1594_PANGAEA_834782 |
| institution | PANGAEA |
| language | en |
| publishDate | 2014 |
| publisher | PANGAEA |
| record_format | pangaea |
| spellingShingle | Magnetic properties of maar lake sediments from Otago, New Zealand Fox, Bethany R Storrs Wartho, Jo-Anne Wilson, Gary S Lee, Daphne E Nelson, Faye E Kaulfuss, Uwe DRILL; Drilling/drill rig; FH2; Foulden Maar, Otago, New Zealand Foulden Maar is a highly resolved maar lake deposit from the South Island of New Zealand comprising laminated diatomite punctuated by numerous diatomaceous turbidites. Basaltic clasts found in debris flow deposits at the base of the cored sedimentary sequence yielded two new 40Ar/39Ar dates of 24.51±0.24 Ma and 23.38±0.24 Ma (2sigma). The younger date agrees within error with a previously published 40Ar/39Ar date of 23.17±0.19 Ma from a basaltic dyke adjacent to the maar crater. The diatomite is inferred to have been deposited over several tens of thousands of years in the latest Oligocene/earliest Miocene, and may have overlapped with the period of rapid glaciation and subsequent deglaciation of Antarctica known as the Mi-1 event. Sediment magnetic properties and SEM measurements indicate that the magnetic signal is dominated by pseudo-single domain pyrrhotite. The most likely source of detrital pyrrhotite is schist country rock fragments from the inferred tephra ring created by the phreatomagmatic eruption that formed the maar. Variations in magnetic concentration and lamina thickness indicate a decrease in erosional input and increase in diatom productivity throughout the depositional period, suggesting a long-term (tens of thousands of years) climatic change in New Zealand in the latest Oligocene/earliest Miocene. |
| title | Magnetic properties of maar lake sediments from Otago, New Zealand |
| topic | DRILL; Drilling/drill rig; FH2; Foulden Maar, Otago, New Zealand |
| url | https://doi.org/10.1594/PANGAEA.834782 |