Paleomagnetic and rock magnetic properties of ODP Leg 173 sites, west Iberia continental margin

We present detailed paleomagnetic and rock magnetic results of rock samples recovered during Leg 173. The Leg 173 cores display a multicomponent magnetization nature. Variations in magnetic properties correlate with changes in lithology that result from differences in the abundance and size of magnetic minerals. The combined investigation suggests that the magnetic properties of the "fresher" peridotite samples from Site 1070 are controlled mainly by titanomagnetite, with a strong Verwey transition in the vicinity of 110 K, and with field- and frequency-dependent susceptibility curves that resemble those of titanomagnetites. These results are in excellent agreement with thermomagnetic characteristics where titanomagnetites with Curie temperature ~580°C were identified from the "fresher" peridotites. In contrast to the magnetic properties observed from the "fresher" peridotites, the low-temperature curves for the "altered" peridotites did not show any Verwey transition. Thermomagnetic analysis using the high-temperature vibrating sample magnetometer also failed to show evidence for titanomagnetites. The remanent magnetization is carried by a thermally unstable mineral that breaks down at ~420°C, probably maghemite. The field- and frequency-dependent relationships are also directly opposite to those in the reversal zone, with no signs of titanomagnetite characteristics. Altogether, these rock magnetic data seem to be sensitive indicators of alteration and support the contention that maghemite is responsible for the magnetic signatures displayed in the altered peridotites of the upper section. The magnetic minerals of the basement rocks from Sites 1068, 1069, and 1070 are of variable particle size but fall within the pseudo-single-domain size range (0.2-14 µm). The average natural remanent magnetization (NRM) intensity of recovered serpenitinized peridotite is typically on the order of 20 mA/m for samples from Site 1068, but ~120 mA/m for samples from Site 1070. The much stronger magnetization intensity of Site 1070 is apparently in excellent agreement with the observed magnetic anomaly high. Nearly half of the NRM intensity remained after 400°C demagnetization, suggesting that the remanence can contribute significantly to the marine magnetic anomaly.

Sedimentological and paleomagnetic investigations on two gravity cores and ODP sites 113-690 and 693 off Kapp Norvegia, Antarctic continental margin

Oligocene to Quaternary sediments were recovered from the Antarctic continental margin in the eastern Weddell Sea during ODP Leg 113 and Polarstern expedition ANT-VI. Clay mineral composition and grain size distribution patterns are useful for distinguishing sediments that have been transported by ocean currents from those that were ice-rafted. This, in turn, has assisted in providing insights about the changing late Paleogene to Neogene sedimentary environment as the cryosphere developed in Antarctica. During the middle Oligocene, increasing glacial conditions on the continent are indicated by the presence of glauconite sands, that are interpreted to have formed on the shelf and then transported down the continental slope by advancing glaciers or as a result of sea-level lowering. The dominance of illite and a relatively high content of chlorite suggest predominantly physical weathering conditions on the continent. The high content of biogenic opal from the late Miocene to the late Pliocene resulted from increased upwelling processes at the continental margin due to increased wind strength related to global cooling. Partial melting of the ice-sheet occurred during an early Pliocene climate optimum as is shown by an increasing supply of predominantly current-derived sediment with a low mean grain size and peak values of smectite. Primary productivity decreased at ~ 3 Ma due to the development of a permanent sea-ice cover close to the continent. Late Pleistocene sediments are characterized by planktonic foraminifers and biogenic opal, concentrated in distinct horizons reflecting climatic cycles. Isotopic analysis of AT. pachyderma produced a stratigraphy which resulted in a calculated sedimentation rate of 1 cm/k.y. during the Pleistocene. Primary productivity was highest during the last three interglacial maxima and decreased during glacial episodes as a result of increasing sea-ice coverage.

A catalogue of 1625 stars between 39o and 41o South declination for the equinox 1900-0 selected as reference points for the Astrographic catalogue,

T.p. missing.

Ueber die lateinische Declination und Conjugation.

Mode of access: Internet.

Die declination der drei geschlechter des substantivs im niederösterreichischen dialekt. Mit zwei anhängen über anomala, über eigennamen und fremdwörter in derselben mundart.

Mode of access: Internet.

Verzeichniss von 5563 telescopischen Sternen vördlich von +15⁰ und südlich von -15⁰ Declination, welche in den Münchener Zonen-Beobachtungen vorkommen, reducirt auf den Anfang des Jahres 1850, nebst zwei Nachträgen zu den früheren Stern-Verzeichnissen.

Mode of access: Internet.

Verzeichniss bon 3571 telescopischen Sternen zwischen +9⁰ und +15⁰ Declination welche in den Münchener Zonen-Beobachtungen vorkommen, reducirt auf den Anfang des Jahres 1850.

Mode of access: Internet.

Verzeichniss von 4093 telescopischen Sternen zwischen -9⁰ und -15⁰ Declination, welche in den Münchener Zonen-Beobachtungen vorkommen, reducirt auf den Anfang des Jahres 1850.

Mode of access: Internet.

Photographische Himmelskarte. Zone + 31⁰ bis + 40⁰ Declination ...

Mode of access: Internet.

Die Declination der Substantiva in der Oïl-Sprache. I. Bis auf Crestiens de Troie...

Includes Vita.

Magnetic declination in the United States.

1910, by R.L. Faris; 1915- , by D.L. Hazard (1935, with W.N. McFarland)

Die Declination im Sanskrit.

Aus den Mémoires de l'Académie impériale des sciences de St. Pétersbourg; Sciences politiques etc. 6. sér., t. 7.

Meridian-beobachtungen von sternen in der zone 65⁰-70⁰ nördlicher declination

At head of title: Publication des Universitäts-observatoriums in Kristiania.