Physical Sciences and Mathematics Commons^™

Agenda: Hard Times On The Colorado River: Drought, Growth And The Future Of The Compact, University Of Colorado Boulder. Natural Resources Law Center, Western Water Assessment (Program), Colorado Water Conservation Board, Center For Advanced Decision Support For Water And Environmental Systems, Hydrosphere Resource Consultants, Rocky Mountain Mineral Law Foundation, Colorado Foundation For Water Education, Patrick, Miller & Kropf, P.C., William & Flora Hewlett Foundation

Hard Times on the Colorado River: Drought, Growth and the Future of the Compact (Summer Conference, June 8-10)

Sponsors and Contributors: Colorado Water Conservation Board, Center for Advanced Decision Support for Water and Environmental Systems, Western Water Assessment, CU-CIRES/NOAA, Hydrosphere Resource Consultants, Rocky Mountain Mineral Law Foundation, Colorado Foundation for Water Education, Patrick, Miller & Kropf, P.C., William and Flora Hewlett Foundation.

The Colorado River is approaching a crossroads. For the first time in its history, satisfying water demands in one state may require curtailing legally-recognized uses in another. This is not the first instance of water shortages in the region, and conflict among the seven Colorado River states is certainly not new. But the potential shortages on …

Macrochannels And Their Significance For Flood-Risk Minimisation, West Dapto, New South Wales, E. L. Roper, Ivars Reinfelds, Gerald C. Nanson

Faculty of Science - Papers (Archive)

A prominent characteristic of streams draining catchments in West Dapto, New South Wales, are well developed macrochannels that have formed within alluvial terraces in mid-catchment zones. A detailed hydraulic modelling study using HEC-RAS, HEC-GeoRAS and Arcview GIS indicates that these macrochannels are scaled to accommodate high magnitude floods. They offer a significant degree of natural protection from flood events up to and in excess of 100 years recurrence interval, essentially by operating as 'bankfull' channels during such events. Macrochannel landforms can be clearly distinguished and mapped on fine-scale digital elevation models (DEMs) and other GIS data sources such as rectified …

New Pieces To The Archaean Terrane Jigsaw Puzzle In The Nuuk Region, Southern West Greeland: Steps In Transforming A Simple Insight Into A Complex Regional Tectonothermal Model, Clark R L Friend, Allen Phillip Nutman

Faculty of Science - Papers (Archive)

In the south of the Nuuk region of West Greenland our 1980s mapping recognized four Archaean gneiss terranes (Færingehavn, Tre Brødre, Tasiusarsuaq and Akia terranes) with different protolith ages and separate early tectonothermal histories. Later in the Archaean these were juxtaposed and then experienced the same 2700-2500 Ma tectonothermal events. Here we abandon extrapolation of only these four terranes across the whole region, and distinguish two new terranes in the NE. The northernmost Isukasia terrane (previously regarded as the northernmost exposure of the Færingehavn terrane) consists of Palaeoarchaean rocks (>3600 Ma) tectonically bounded on its south by the 3075-2960 …

Complex 3670-3500 Ma Orogenic Episodes Superimposed On Juvenile Crust Accreted Between 3850 And 3690 Ma, Itsaq Gneiss Complex, Southern West Greenland, Clark R L Friend, Allen Phillip Nutman

Faculty of Science - Papers (Archive)

The Itsaq Gneiss Complex of the Nuuk region, southern West Greenland, is dominated by 3850-3690 Ma tonalites intruded into and intercalated with lesser amounts of different ≥3850-3700 Ma supracrustal units. Published wholerock Sr and Nd isotopic studies demonstrate that the tonalites are juvenile crustal additions from a depleted mantle source. From our field studies and SHRIMP U/Pb zircon dating, we argue that this juvenile crustal accretion was spread over ca. 170 m.yr. (≥3850-3690 Ma). Following 3850-3690 Ma juvenile crustal accretion events, the evolution of the Itsaq Gneiss Complex continued with numerous crustal-reworking events between 3670 and 3500 Ma. Examples of …

Age, Petrogenesis And Metamorphism Of The Syn-Collisional Proven Igneous Complex, West Greenland, Kristine Thrane, J Baker, J Connelly, Allen Phillip Nutman

Faculty of Science - Papers (Archive)

The Paleoproterozoic Prøven Igneous Complex (PIC) in West Greenland extends from ca. 72°15′ to 73°10′N, approximately 500 km north of the subduction-related intrusive complex in the core of the +1100 km wide, asymmetric collisional Nagssugtoqidian-Rinkian Orogen. A new U-Pb SHRIMP age for the PIC of 1869±9 Ma indicates that it intruded synchronously with the main collisional phase of the orogen into the passive margin side of the collision. Sm-Nd and Lu-Hf isotopic and A-type geochemical signatures are compatible with its derivation from melted Archean lower crustal material contaminated to varying degrees by pelitic sedimentary rocks of the Karrat Group. The …