The roles of flux- and decompression melting and their respective fractionation lines for continental crust formation: Evidence from the Kohistan arc

Delamination and foundering of the lower continental crust (LCC) into the mantle is part of the crust-forming mechanism. However, knowledge of the composition and mineralogy of the preserved or delaminated LCC over geological timescales remains scarce. We provide a synopsis of recent research within the Kohistan arc (Pakistan) and demonstrate that hydrous and less hydrous liquid lines of descent related to flux assisted and decompression mantle melting, respectively, produce compositionally different lower crustal rocks. The argument refers to two lower crustal sections exposed in Kohistan, the older Southern Plutonic Complex (SPC) and the younger Chilas Complex. The SPC typifies a hydrous, high-pressure fractionation sequence of olivine-pyroxenes-garnet-Fe/Ti-oxide-amphibole-plagioclase. The Chilas Complex illustrates a less hydrous fractionation sequence of olivine-clinopyroxene-orthopyroxene-plagioclase-amphibole. Despite the similarity of the Chilas Complex rocks to proposed lower crust compositions, the less hydrous fractionation results in unrealistically small volumes of silica-rich rocks, precluding the Chilas Complex gabbros to represent the magmatic complement to the upper crust. The composition of the SPC lower crust differs markedly from bulk lower crust estimates, but is complementary to silica-rich rocks exposed along this section and in the Kohistan batholith. These observations inspire a composite model for the formation of continental crust (CC) where the negatively buoyant delaminated and the buoyant preserved lower continental crusts (LCC) differ in genesis, mineralogy, and composition. We propose that the upper, non-sedimentary subsequent removal of the complementary, negatively buoyant garnet-pyroxene-amphibole-plagioclase-rich cumulates. In contrast, the LCC, which is buoyant and preserved over geological timescales, is formed by less hydrous parental mantle melts. We suggest that the bulk continental crust composition is related to mixing of these petrologically not directly related end members. Published by Elsevier B.V.

US 30 Proposed Expansion Benton County, Iowa, Enviornmental Assessment and Section 4(f) De Minimis Impact Finding, June 11, 2012

The Transportation Equity Act of the 21st Century (TEA-21) (23 CFR) mandated environmental streamlining in order to improve transportation project delivery without compromising environmental protection. In accordance with TEA-21, the environmental review process for this project has been documented as a Streamlined Environmental Assessment (EA). This document addresses only those resources or features that apply to the project. This allowed study and discussion of resources present in the study area, rather than expend effort on resources that were either not present or not impacted. Although not all resources are discussed in the EA, they were considered during the planning process and are documented in the Streamlined Resource Summary, shown in Appendix A. The following table shows the resources considered during the environmental review for this project. The first column with a check means the resource is present in the project area. The second column with a check means the impact to the resource warrants more discussion in this document. The other listed resources have been reviewed and are included in the Streamlined Resource Summary.

Implementing 2008 Iowa Acts, Chapter 1187, Section 5 Tribal TANF Matching Fund Formula Recommendation, December 29, 2008

The Iowa Department of Human Services in consultation with the Winnebago Tribe of Nebraska submits the following recommendations as directed by 2008 Iowa Acts, Chapter 1187, Section 5.

[Exposition universelle, Paris, 1889, 10 phot. des objets exposés à la section I, "Anthropologie, ethnographie, archéologie", don Eugène de Rozière]

Donateur : Rozière, Eugène de (1820-1896)

DMC Section from Iowa’s 2007

This document is the DMC Section of Iowa’s 2007 JJDP Act formula grant three year plan update. The bulk of this 2007 plan is an “update” of the program plan completed since submission of the original 2006 plan. The Division of Criminal and Juvenile Justice Planning (CJJP) wrote Iowa’s three year plan update. CJJP is the state agency responsible for administering the JJDP Act in Iowa. Federal officials refer to state administering agencies as the state planning agency (SPA). The Plan was developed and approved by Iowa’s Juvenile Justice Advisory Council. That Council assists with administration of the JJDP Act, and also provides guidance and direction to the SPA, the Governor and the legislature regarding juvenile justice issues in Iowa. Federal officials refer to such state level groups as state advisory groups (SAG’s). The acronyms SPA and SAG are used through this report.

DMC Section: 2009 State of Iowa Juvenile Justic and Delinquency Prevention Act Formula Grant Update, March 2009

This document is the DMC Section of Iowa’s 2009 federal Juvenile Justice and Delinquency Prevention Act (JJDP Act) formula grant three year plan update. The Division of Criminal and Juvenile Justice Planning (CJJP) wrote this update. CJJP is the state agency responsible for administering the JJDP Act in Iowa. Federal officials refer to state administering agencies as the state planning agency (SPA). The Plan was developed and approved by Iowa’s Juvenile Justice Advisory Council. That Council assists with administration of the JJDP Act, and also provides guidance and direction to the SPA, the Governor and the legislature regarding juvenile justice issues in Iowa. Federal officials refer to such state level groups as state advisory groups (SAG’s). The acronyms SPA and SAG are used through this report.

Unravelling the interaction between tectonic and sedimentary processes during lithospheric thinning in the Alpine Tethys margins

The discovery of exhumed continental mantle and hyper-extended crust in present-day magma-poor rifted margins is at the origin of a paradigm shift within the research field of deep-water rifted margins. It opened new questions about the strain history of rifted margins and the nature and composition of sedimentary, crustal and mantle rocks in rifted margins. Thanks to the benefit of more than one century of work in the Alps and access to world-class outcrops preserving the primary relationships between sediments and crustal and mantle rocks from the fossil Alpine Tethys margins, it is possible to link the subsidence history and syn-rift sedimentary evolution with the strain distribution observed in the crust and mantle rocks exposed in the distal rifted margins. In this paper, we will focus on the transition from early to late rifting that is associated with considerable crustal thinning and a reorganization of the rift system. Crustal thinning is at the origin of a major change in the style of deformation from high-angle to low-angle normal faulting which controls basin-architecture, sedimentary sources and processes and the nature of basement rocks exhumed along the detachment faults in the distal margin. Stratigraphic and isotopic ages indicate that this major change occurred in late Sinemurian time, involving a shift of the syn-rift sedimentation toward the distal domain associated with a major reorganization of the crustal structure with exhumation of lower and middle crust. These changes may be triggered by mantle processes, as indicated by the infiltration of MOR-type magmas in the lithospheric mantle, and the uplift of the Brianconnais domain. Thinning and exhumation of the crust and lithosphere also resulted in the creation of new paleogeographic domains, the Proto Valais and Liguria-Piemonte domains. These basins show a complex, 3D temporal and spatial evolution that might have evolved, at least in the case of the Liguria-Piemonte basin, in the formation of an embryonic oceanic crust. The re-interpretation of the rift evolution and the architecture of the distal rifted margins in the Alps have important implications for the understanding of rifted margins worldwide, but also for the paleogeographic reconstruction of the Alpine domain and its subsequent Alpine compressional overprint.

Tectonic subsidence of the Lomonosov Ridge

The Cenozoic sedimentary record revealed by the Integrated Ocean Drilling Program's Arctic Coring Expedition (ACEX) to the Lomonosov Ridge microcontinent in 2004 is characterized by an unconformity attributed to the period 44-18 Ma. According to conventional thermal kinematic models, the microcontinent should have subsided to >1 km depth owing to rifting and subsequent separation from the Barents-Kara Sea margin at 56 Ma. We propose an alternative model incorporating a simple pressure-temperature (P-T) relation for mantle density. Using this model, we can explain the missing stratigraphic section by post-breakup uplift and erosion. The pattern of linear magnetic anomalies and the spreading geometry imply that the generation of oceanic crust in the central Eurasia Basin could have been restricted and confined by non-volcanic thinning of the mantle lithosphere at an early stage (ca. 56-40 Ma). In response to a rise in temperature, the mantle mineral composition may have changed through breakdown of spinet peridotite and formation of less dense plagioclase peridotite. The consequence of lithosphere heating and related mineral phase transitions would be post-breakup uplift followed by rapid subsidence to the deep-water environment observed on the Lomonosov Ridge today.

DMC Section: 2008 State of Iowa Juvenile Justice and Delinquency Prevention Act Formula Grant Update, March 2009

This document is the DMC Section of Iowa’s 2009 federal Juvenile Justice and Delinquency Prevention Act (JJDP Act) formula grant three year plan update. The Division of Criminal and Juvenile Justice Planning (CJJP) wrote this update. CJJP is the state agency responsible for administering the JJDP Act in Iowa. Federal officials refer to state administering agencies as the state planning agency (SPA). The Plan was developed and approved by Iowa’s Juvenile Justice Advisory Council. That Council assists with administration of the JJDP Act, and also provides guidance and direction to the SPA, the Governor and the legislature regarding juvenile justice issues in Iowa. Federal officials refer to such state level groups as state advisory groups (SAG’s). The acronyms SPA and SAG are used through this report.

A global marine sedimentary response to the end-Permian mass extinction: Examples from southern Turkey and the western United States

The end-Permian mass extinction greatly diminished marine diversity and brought about a whole-scale restructuring of marine ecosystems; these ecosystem changes also profoundly affected the sedimentary record. Data presented here, attained through facies analyses of strata deposited during the immediate aftermath of the end-Permian mass extinction (southern Turkey) and at the close of the Early Triassic (southwestern United States), in combination with a literature review, show that sedimentary systems were profoundly affected by: (1) a reduction in biotic diversity and abundance and (2) long-term environmental fluctuations that resulted from the end-Permian crisis. Lower Triassic strata display widespread microbialite and carbonate seafloor fan development and contain indicators of suppressed infaunal bioturbation such as flat-pebble conglomerates and wrinkle structures (facies considered unusual in post-Cambrian subtidal deposits). Our observations suggest that depositional systems, too, respond to biotic crises, and that certain facies may act as barometers of ecologic and environmental change independent of fossil assemblage analyses. Close investigation of facies changes during other critical times in Earth history may serve as an important tool in interpreting the ecology of metazoans and their environment.

2013 Elder Abuse Task Force Final Report Pursuant to Senate File 446, Section 50, December 13, 2013

Per the guidance of the Legislative Elder Abuse Prevention and Intervention Interim Committee, a prioritization of the implementation recommendations and proposed legislation are below listed in the order determined in the 2012 Elder Abuse Task Force Report.