Petrology and geochemistry of sideromelane glass shards from Pleistocene as layers north and south of Gran Canaria

Major elements, S, F, Cl concentrations and relative proportions of S6+ to total S were analyzed with electron microprobe in sideromelane glass shards from Pleistocene volcaniclastic sediments drilled during ODP Leg 157. Glasses are moderately to strongly evolved and represent a spectrum from alkali basalt, basanite and nephelinite through hawaiite, mugearite and tephrite to phonolitic tephrite. Measured S6+/SumS (0.03±0.98) and calculated Fe2+/Fe3+ (2.5±5.8) ratios in the melt yield preeruptive redox conditions ranging from NNO-1.4 to NNO+2.1. The morphology of the glass shards, variations of S and Cl concentrations (0.010±0.127 wt% S, 0.018±0.129 wt% Cl), calculated preeruptive temperatures (1030±1200 °C) and oxygen fugacities suggest that glasses deposited even within the same ash layers have diverse origin and may have resulted from both submarine and subaerial eruptions. Most vesicle-free glasses are characterized by high concentrations of S and represent undegassed or slightly degassed submarine lavas, whereas vesiculated glasses with low concentrations of S and Cl are strongly degassed and can be ascribed to the eruptions in shallow water or on land. Sideromelane glass shards at Sites 953 are thought to have resulted from submarine eruptions northeast of Gran Canaria, glasses at Site 954 represent mostly volcaniclastic material of shallow water submarine and subaerial eruptions on Gran Canaria and Tenerife, and glasses deposited at Site 956 resulted from submarine or explosive eruptions on Tenerife.

Data on mineral composition of volcanic glass and radiocarbon age of Upper Quaternary sediments from the Sea of Okhotsk

Lithological horizons have been distinguished in sediments cores from different parts of the Sea of Okhotsk based on primary descriptions of sediments and smear slides, and analyses of contents of both calcium carbonate and organic carbon, and opal. Sediment lithology has been correlated with oxygen isotope records and the standard isotope scale and radiocarbon data by AMS method for three cores studied in detail. This allowed to determine in detail periods of carbonaceous and diatomaceous ooze accumulation in the Sea of Okhotsk. Changes in magnetic susceptibility and grain size composition of sediments have been also compared with oxygen-isotope curves and radiocarbon datings. Obtained results confirm that variations in magnetic susceptibility are related with oxygen-isotope stages and influenced by climatic changes. Tephra interlayers K0, TR, K2, K3 have been identified by mineralogical analyses in all studied cores. Stratigraphic location of these tephra interlayers in detailed studied cores and their radiocarbon ages (8.1, 8.05, 26.8, and about 60 ka, respectively) provided base correlation between the interlayers and volcanic eruptions on the Kamchatka Peninsula and the Kuril Islands. This allows to use the former ones as time markers for deep-sea sediments of the Sea of Okhotsk. New lithostratigraphic and tephrochronologic data obtained allowed to correlate Upper Quaternary sediments from the Sea of Okhotsk.

(Table 1) Geochemistry of glass shards at DSDP Leg 84 Holes

Three Leg 84 sites provided a good record of explosive volcanism onshore (in Central America). Ash layers and many ashy pods are interbedded in Recent to Oligocene strata. Evidence of the main periods of activity was noted in Recent to upper Pleistocene, Pliocene-Pleistocene, lower Pliocene to upper Miocene, lower Miocene, and upper Oligocene. Noticeable traces of older volcanism were found in upper Eocene strata. The chemical analyses of glass shards show a dacitic to rhyolitic composition with a low to moderate calc-alkalinity. A preliminary distinction of samples in three geochemical groups according to their K2O/SiO2 contents is done to test a magmatic evolution. Comparisons are made with Leg 67 and on-land data.

Top left: F. Sorg, house sign and ornamental painter, dealer in oils, varnishes, glass, 26 & 28 East Washington St., Ann Arbor, Mich. Left: Res. of Mrs. Chas. Behr, Ann Arbor, Mich.; Botttom: Res. of Andrew Ten Brook, Ann Arbor, Mich. (na11,064)

Ann Arbor, Mich. residences and business. Publication information: Chicago, Ill. : Everts & Stewart, 1874.

Metal-glass museum cases of the Wistar institute; three working drawings.

Signed: M.J. Greenman.

Morse's manual of art : a self teacher in all branches of deocrative art, embracing almost every variety of painting and drawing, on china, glass, velvet, canvas, paper and wood : the secret of all glass transparencies, sketching from nature, pastel and crayon drawing, etc. : illustrated /

Mode of access: Internet.

Wage scale and working rules agreed upon by the machine glass bottle and jar manufacturers and the Glass Bottle Blowers' Association of the United States and Canada, blast ...

Description based on: 1913/1914.