Provenance of Cretaceous through Eocene strata of the Four Corners region: Insights from detrital zircons in the San Juan Basin, New Mexico and Colorado

Cretaceous through Eocene strata of the Four Corners region provide an excellent record of changes in sediment provenance from Sevier thin-skinned thrusting through the formation of Laramide block uplifts and intra-foreland basins. During the ca. 125–50 Ma timespan, the San Juan Basin was flanked by the Sevier thrust belt to the west, the Mogollon highlands rift shoulder to the southwest, and was influenced by (ca. 75–50 Ma) Laramide tectonism, ultimately preserving a >6000 ft (>2000 m) sequence of continental, marginal-marine, and offshore marine sediments. In order to decipher the influences of these tectonic features on sediment delivery to the area, we evaluated 3228 U-Pb laser analyses from 32 detrital-zircon samples from across the entire San Juan Basin, of which 1520 analyses from 16 samples are newly reported herein. The detrital-zircon results indicate four stratigraphic intervals with internally consistent age peaks: (1) Lower Cretaceous Burro Canyon Formation, (2) Turonian (93.9–89.8 Ma) Gallup Sandstone through Campanian (83.6–72.1 Ma) Lewis Shale, (3) Campanian Pictured Cliffs Sandstone through Campanian Fruitland Formation, and (4) Campanian Kirtland Sandstone through Lower Eocene (56.0–47.8 Ma) San Jose Formation. Statistical analysis of the detrital-zircon results, in conjunction with paleocurrent data, reveals three distinct changes in sediment provenance. The first transition, between the Burro Canyon Formation and the Gallup Sandstone, reflects a change from predominantly reworked sediment from the Sevier thrust front, including uplifted Paleozoic sediments and Mesozoic eolian sandstones, to a mixed signature indicating both Sevier and Mogollon derivation. Deposition of the Pictured Cliffs Sandstone at ca. 75 Ma marks the beginning of the second transition and is indicated by the spate of near-depositional-age zircons, likely derived from the Laramide porphyry copper province of southern Arizona and southwestern New Mexico. Paleoflow indicators suggest the third change in provenance was complete by 65 Ma as recorded by the deposition of the Paleocene Ojo Alamo Sandstone. However, our new U-Pb detrital-zircon results indicate this transition initiated ∼8 m.y. earlier during deposition of the Campanian Kirtland Formation beginning ca. 73 Ma. This final change in provenance is interpreted to reflect the unroofing of surrounding Laramide basement blocks and a switch to local derivation. At this time, sediment entering the San Juan Basin was largely being generated from the nearby San Juan Mountains to the north-northwest, including uplift associated with early phases of Colorado mineral belt magmatism. Thus, the detrital-zircon spectra in the San Juan Basin document the transition from initial reworking of the Paleozoic and Mesozoic cratonal blanket to unroofing of distant basement-cored uplifts and Laramide plutonic rocks, then to more local Laramide uplifts.National Science Foundation (NSF grant EAR-1649254

Bureaucracy, class, and ideology : the Vancouver Trades and Labour Council, 1889-1909

This dissertation is an examination of bureaucracy, class, and ideology in the labour movement. It seeks to understand what is meant by the term labour bureaucracy and to determine the degree to which bureaucracy shaped ideology in the Vancouver Trades and Labour Council from 1889 to 1909. -- The first section is an analysis of the theoretical literature and historiography of the labour bureaucracy. As well as providing an overview of the topic, the thesis tries to formulate a different definition of the labour bureaucracy, one that focuses on the power of the bureaucrats, rather than their ideology. The second section is a study of the officials and leaders that made up the VTLC from its beginning in 1889 to the founding of the B.C. Federation of Labour twenty years later. In this section, the ideology of the council is examined to evaluate the impact of bureaucracy on the labour movement. The policies and structure of the council are studied in detail to show how the separation of the leaders from the led developed over time and to demonstrate why bureaucratic solutions - the hiring of experts, reliance on government intervention, the routinization of procedures, and the creation of labour institutions - were taken and to outline the effect they had. The conflict between labourists and socialists is examined closely to suggest first that bureaucracy is not limited to labour leaders of any single ideology, and second, that the needs of the labour movement and the demands of bureaucracy itself tended to soften ideological battles. Even with the ascension of socialists to the council in 1907-1909, continuity remained the hallmark of the labour council, in part because socialists had no particular commitment to rank-and-file control of the labour movement. Finally, the lives and class positions of the labour leaders are illustrated to try to shed some light on the ways in which bureaucracy, class, and ideology become intertwined