27 research outputs found
Diagenetic provinces of the Verrucano Lombardo and Val Gardena sandstones (Permian), southern Alps, Italy.
No full textDiagenetic sequences and porosity in the arkosic and lithic Verrucano Lombardo and Val Gardena sandstones in N Italy are controlled dominantly by framework mineralogy and tectonic history. These stratigraphically equivalent Permian sandstones were deposited in various non-marine environments during an early stage of rifting at the base of the Alpidic cycle: they consist dominantly of quartz, feldspars and acidic to intermediate volcanic rock fragments. Source terrains consist of underlying Permian volcanic and terrigenous rocks of the pre-Permian crystalline basement. Three distinct diagenetic provinces have been differentiated, based on 1) the presence and nature of carbonate cement and/or replacement; 2) the presence of quartz cement; 3) the presence of kaolinization of detrital K-feldspar; and 4) the degree of recrystallization of the detrital clay matri
Reservoir quality of sandstones in the Naknek and Kaguyak Formations: Field observations
No full textConrad III and the Second Crusade in the Byzantine Empire and Anatolia, 1147
No full textThis thesis aims to revise the established history of the passage of the Second Crusade through the Byzantine Empire and Anatolia in 1147. In particular, it seeks to readdress the ill-fated advance of the army nominally headed by King Conrad III Staufen of Germany towards Ikonion, the fledging Seljuk capital of Rūm.
The work consists of four mutually supportive parts. Part I serves to introduce the thesis, the historiographical trends of the current scholarship, and the Byzantine notion of the Latin 'barbarian', a stock, literary representation of the non-Greek other which distorts the Greek textual evidence.
Part II analyses the source portrayal of particular incidents as the army marched through the Byzantine Empire, provides analyses of those events based on new approaches to interpreting the sources and a consideration of the army's logistical arrangements, and argues that the traditional historiography has been and continues to be subject to textual misrepresentation.
An understanding of the topology of Anatolia is required to appreciate why the army failed to reach Ikonion. Part III therefore consists of chapters devoted to the geography of Anatolia, the form, function and the population density of the typical twelfth-century town, the country's changeable medieval geopolitical landscape, and the settlement patterns and the way of life of western Anatolia's pastoral-nomadic warriors.
Part IV revisits the Latin, Syriac and Greek sources which constitute the written history of the crusade in Anatolia, analyses the concerns of the army's executive decision makers within geopolitical, logistical, topographical and tactical frameworks, and offers a reconsideration of the established location of where the army ceased to advance on Ikonion, and a new version of the circumstances which led to the decision to retreat
Reservoir quality of 84 Tertiary sandstones from three exploratory wells, Bristol Bay basin, Alaska Peninsula
No full textReconnaissance stratigraphy of the Red Glacier Formation (Middle Jurrassic) near Hungryman Creek, Cook Inlet Basin, Alaska
No full textSedimentary petrology and reservoir quality of the Middle Jurassic Red Glacier Formation, Cook Inlet forearc basin: Initial impressions
No full textNonmarine facies in the Late Triassic(?) to Early Jurassic Horn Mountain Tuff Member of the Talkeetna Formation, Horn Mountain, Lower Cook Inlet Basin, Alaska
No full textHolocene and Palaeogene arkoses of the Massif Central France: mineralogy, chemistry, provenance and hydrothermal alteration of the type arkose.
No full textPaleogene arkoses of the Auvergne region of France represent the type arkose originally described by Brongniart (1826). They are alluvial-fan and fluvial deposits including traction-current sandstones (arenites) and matrix-rich debris-flow deposits (wackes). Locally, they have been extensively altered by geothermal waters related to nearby Tertiary-Holocene volcanic activity. The alteration is typified by leaching of detrital grains and precipitation of ubiquitous chert cement. The average Gazzi-Dickinson composition of unaltered arenites is Q 40 F 60 L 0 , with K/F (potash feldspar/total feldspar) = 0.63. Altered arenites have an average composition of Q 55 F 43 L 2 , with K/F= 0.73, reflecting loss of plagioclase due to intense alteration. When secondary chert is included with detrital quartz and chert, the altered rocks have an average composition of Q 66 F 32 L 1 , emphasizing silica enrichment associated with alteration. Holocene sands derived from crystalline basement of the Massif Central have the same provenance as the Paleogene sandstones. They have an average Gazzi-Dickinson composition of Q 46 F 49 L 5 with K/F = 0.52 and compare favorably with their unaltered ancient counterparts. Arkosic alluvium at Roosevelt Hot Springs, Utah is believed to represent a modern analog for alteration of the Auvergne sandstones. The alluvium has been altered and cemented with silica by geothermal waters at near-surface conditions in the epithermal zone. Chemical analyses of 130 sand and rock samples demonstrate original sediment compositions and changes due to hydrothermal alteration. Holocene sands and unaltered Paleogene clastics are compositionally similar and show variation trends similar to feldspathic clastics derived from granitic basement in other basins. Silica enrichment in the altered sandstones causes dilution of all other elements as an effect of constant summation. Consequently, most element abundances decline proportionately with silica dilution. Na and Rb, however, are reduced below the levels predicted by dilution due to plagioclase and biotite destruction. As a result, K/Rb ratios are higher in the altered sandstones. Ba, S, SO 4 , As, and Sb are enriched in the altered rocks by precipitation from hydrothermal solutions. Barium is in barite as fracture-filling veins and scattered patches in sandstone matrix. Destruction of mafic minerals during alteration released Fe, Co, Cr, Ni, Zn, Pb, and Th that later precipitated as oxides and sulfides in fractures and locally in chert matrix in the sandstones
Hydrocarbon-bearing sandstone in the Upper Jurassic Naknek formation on the south shore of Kamishak Bay
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