The Formation of Eskers

Ever since work has been in progress in glaciated regions, long, narrow, winding, steep-sided, conspicuous ridges of gravel and sand have been recognized by geologists. They are best developed and were first recognized as distinct phases of drift in Sweden, where they are called Osar. The term Osar has the priority over other terms, but in this country, probably for phonic reasons, the Irish term Esker has come into use. With apologies to Sweden, Esker will be used in the present paper. Other terms which have been applied to these ridges in various parts of the world are serpent-kames, serpentine kames, horsebacks, whalebacks, hogbacks, ridges, windrows, turnpikes, back furrows, ridge furrows, morriners, and Indian roads

Preliminary Report on Geological Work in Northeastern Iowa

Field work is now being carried on in northeastern Iowa, by field classes and graduate students in the Department of Geology in the State University of Iowa, under the direction of the writer. The first work was done in the summer of 1913, in the driftless area of Allamakee, Clayton, and Dubuque Counties, by a field class. The most detailed work has been done by Mr. A. J. Williams who has written a Master\u27s thesis on a small area around Dubuque. The work will be continued during the coming summer, and will probably be carried on in following summers, until the outstanding problems of the region have been solved. Perhaps it may then be carried into other parts of the driftless area in adjoining states

The Prairie du Chien - St. Peter Unconformity in Iowa

Unconformable relations between the Prairie du Chien and St. Peter formations have long been known in Minnesota, Wisconsin, Illinois and Missouri. The existence of this unconformity in Iowa, though long suspected, has never been demonstrated, or if it has been known to exist here, the fact has not been recorded. There is nothing in the reports of the State Geological Survey suggesting anything but conformable relations between the two formations

The Address of the President: Water Problems

Few truisms have wider application than familiarity breeds contempt. J\Ian takes for granted common and therefore important things such as sunshine, clouds, rain, summer heat and winter cold, the normal winds and calms, the air we breathe, soil, ordinary hills and valleys. They do not attract the attention of the general population. It is true that every twenty-four hours more than a million tons of sand, silt, mud and dissolved salts are carried in Mississippi River past the Carrollton gage at New Orleans and dumped into the Gulf of Mexico. This is too common and familiar - and important – a fact to make the front page. The man has not bitten the dog

The Origin of the St. Peter Sandstone

Originally, all sedimentary rocks were thought to be marine. When the St. Peter sandstone was first recognized as a distinct formation, it was assumed to have had a marine origin. More recently, however, the marine origin of many sediments has been doubted, and the criteria for distinguishing various sorts of sedimentary rocks have been worked out. As early as 1907 evidences were presented for the eolian origin of the St. Peter sandstone, although there are those who have never accepted the evidence as conclusive. In the literature of the subject, the matter is not settled

Macroalgae and Eelgrass Mapping in Great Bay Estuary Using AISA Hyperspectral Imagery.

Results Increases in nitrogen concentration and declining eelgrass beds in Great Bay Estuary have been observed in the last decades. These two parameters are clear indicators of the impending eutrophication for New Hampshire’s estuaries. The NH Department of Environmental Services (DES) in collaboration with the Piscataqua Region Estuaries Partnership adopted the assumption that eelgrass survival can be used as the target for establishing numeric water quality criteria for nutrients in NH’s estuaries. One of the hypotheses put forward regarding eelgrass decline is that an eutrophication response to nutrient increases in the Great Bay Estuary has been the proliferation of nuisance macroalgae, which has reduced eelgrass area in Great Bay Estuary. To determine the extent of this effect, mapping of eelgrass and nuisance macroalgae beds using hyperspectral imagery was suggested. A hyperspectral image was made by SpecTIR in August 2007 using an AISA Eagle sensor. The collected dataset was then used to map eelgrass and nuisance macroalgae throughout the Great Bay Estuary. Here we outline the procedure for mapping the macroalgae and eelgrass beds. Hyperspectral imagery was effective where known spectral signatures could be easily identified. Comprehensive eelgrass and macroalgae maps of the estuary could only be produced by combining hyperspectral imagery with ground-truth information and expert opinion. Macroalgae was predominantly located in areas where eelgrass formerly existed. Macroalgae mats have now replaced nearly 9% of the area formerly occupied by eelgrass in Great Bay

Macroalgae and eelgrass mapping in Great Bay Estuary using AISA hyperspectral imagery

Increase in nitrogen concentration and declining eelgrass beds in Great Bay Estuary have been observed in the last decades. These two parameters are clear indicators of the impending problems for NH’s estuaries. The NH Department of Environmental Services (DES) in collaboration with the New Hampshire Estuaries Project (NHEP) adopted the assumption that eelgrass survival can be used as the water quality target for nutrient criteria development for NH’s estuaries. One of the hypotheses put forward regarding eelgrass decline is that a possible eutrophication response to nutrient increases in the Great Bay Estuary has been the proliferation of nuisance macroalgae, which has reduced eelgrass area in Great Bay Estuary. To test this hypothesis, mapping of eelgrass and nuisance macroalgae beds using hyperspectral imagery was suggested. A hyperspectral imagery was conducted by SpecTIR in August 2007 using an AISA Eagle sensor. The collected dataset was used to map eelgrass and nuisance macroalgae throughout the Great Bay Estuary. This report outlines the configured procedure for mapping the macroalgae and eelgrass beds using hyperspectral imagery. No ground truth measurements of eelgrass or macroalgae were collected as part of this project, although eelgrass ground truth data was collected as part of a separate project. Guidance from eelgrass and macroalgae experts was used for identifying training sets and evaluating the classification results. The results produced a comprehensive eelgrass and macroalgae map of the estuary. Three recommendations are suggested following the experience gained in this study: conducting ground truth measurements at the time of the HS survey, acquiring the current DEM model of Great Bay Estuary, and examining additional HS datasets with expert eelgrass and macroalgae guidance. These three issues can improve the classification results and allow more advanced applications, such as identification of macroalgae types