Geology Commons^™

A Microwave Digestion Technique For The Extraction Of Fossil Diatoms From Coastal Lake And Swamp Sediments, Jeffrey Parr, Kathryn Taffs, Christopher Lane

Jeffrey Parr

This study provides an introduction to a microwave digestion technique for the extraction of fossil diatoms from sediments. The microwave technique is compared with the standard diatom extraction technique of Battarbee (Diatom analysis. In: Berglund B.E. (ed.), Handbook of Holocene Palaeoecology and Palaeohydrology. John Wiley and Sons) that uses a combination of dilute hydrochloric acid and hydrogen peroxide and the advantages and disadvantages of their use are discussed. The results suggest that the microwave technique is fast, inexpensive and most importantly produces replicable fossil diatom assemblage data. Small samples sizes are used (0.3 g) for the microwave method thus lower …

The Biscayne Aquifer Of Southeastern Florida, Kevin Cunningham, Lee J. Florea

Lee J Florea, PhD, P.G.

In southeastern Florida, locally delineated, small, poorly explored caves and subtle karst are characteristic of the limestone that composes the unconfined Biscayne aquifer – one of the most permeable aquifers in the world. The main units of the Biscayne aquifer are the Fort Thompson Formation and Miami Limestone, both characterized by eogenetic karst.

Late Quaternary Distribution And Biogeography Of The Southern Lake Eyre Basin (Sleb) Megafauna, South Australia, Steve Webb

Steve Webb

Understanding the population demography, species distribution and biogeography of Australia’s megafauna is essential for understanding their extinction. This process is only just beginning, and this article discusses these aspects while concentrating on a particular region; the southern Lake Eyre Basin (SLEB). It is also the first detailed description of the distribution of megafauna across that region of central Australia. The data are based on an extensive longitudinal study of 41 palaeontological sites spread across 250 000km2. Megafauna adaptation and response to extensive environmental change during the late Quaternary is reflected in the composition and distribution of 21 megafauna species found …

Mountain Building Across A Lithospheric Boundary During Arc Construction: The Cretaceous Peninsular Ranges Batholith In The Sierra San Pedro Martir Of Baja California, Mexico, K Schmidt, S Paterson, Ann Blythe, C Kopf

Ann Blythe

The Jura-Cretaceous Peninsular Ranges batholith (PRB) of Southern and Baja California contains a remarkable example of variation in crustal composition and structure across a batholith-parallel lithospheric-scale discontinuity. This lithospheric boundary between western oceanic-floored and eastern continental-floored crust influenced contractional deformation, arc magmatism, and differential exhumation of western and eastern zones in the batholith during its evolution. In the Sierra San Pedro Martir of Baja California, Mexico, a ca. 20 km wide, doubly vergent fan structure occurs across the PRB basement transition that consists of inward-dipping mylonite thrust sheets on the sides of the fan that gradually transition to a steeply-dipping …

Interregional Comparison Of Karst Disturbance: West-Central Florida And Southeast Italy, Leslie North

Leslie North

Quantitative Assessment Of Climate-Induced Glacier Fluctuation In The Central Himalaya Utilizing Satellite Images., Umesh Haritashya

Umesh Haritashya

Sustainability, Energy, and Environment Seed Grant. Total Amount $10,000. Role: PI. Project duration: January 1, 2009 – December 31, 2009.

Quantitative Paleobiogeography Unraveling Macroevolutionary Patterns In Fossil Plankton Using Geographic Information Systems (Gis) Software And The New Geobiodiversity Database, Daniel Goldman

Daniel Goldman

Funding agency: UDRI Seed Grant Amount: $7,500.00

Hierarchical Modeling: Biogeochemical Processes And Mechanisms That Drives Clay Nano- And Microfabric Development, Kenneth J. Curry, Richard H. Bennett, Paula J. Smithka, Matthew H. Hulbert

Kenneth J. Curry

Conceptual scientific models of clay and clay fabric development can be constructed profitably by considering chemical and physical systems in terms of an ordered hierarchy. We develop here a hierarchical model of early stages of marine sediment development identifying processes and focusing on mechanisms. While the focus of our model is on mechanisms, the physical aspects of the hierarchy are cast in terms of the scale of structure in which the mechanisms occur. Our primary scale of interest is the nanometer (nanofabric) level of organization of sediment fabric. This level is nested below the micrometer (microfabric) level that includes aggregates …

Slip Heterogeneity On A Corrugated Fault, Phillip G. Resor, Vanessa E. Meer

Phillip G Resor

Slip heterogeneity reflects the fundamental physics of earthquake rupture and has been attributed to strong fault patches termed asperities or barriers. We propose that variations in fault-surface orientation due to slip-parallel corrugations may act as geometric asperities and barriers, generating variations in incremental (i.e. due to a single earthquake) slip across a fault surface. We evaluate this hypothesis using observations from the Arkitsa normal fault exposure in central Greece. A scan of the Arkitsa fault surface with 1-m spatial resolution and mm-scale precision reveals corrugations made up of 1–5 m wide synforms, antiforms, and nearly planar fault sections with long …