Based on the Tenth International Basement Tectonics Conference held at the University of Minnesota-Duluth in August 1992, this volume contains 19 papers, 13 of which focus on the Middle Proterozoic Midcontinent Rift. An introductory essay discussing the Middle Proterozoic to Cambrian rifting in central North America is followed by contributions addressing topics including the Midcontinent Rift in Michigan and Minnesota, the Port Coldwell veins of northern Ontario, and petrography and sedimentation in the western Lake Superior region. The last five papers deal with the pre-Mount Simon basins of Ohio, the English Graben and the newly proposed East Continent Rift Complex, the Reelfoot Rift/Rough Creek Graben in the evolution of the Illinois Basin, and the A-type sheet granites in the Oklahoma Aulacogen of Cambrian age. Bandw illustrations. Annotation copyrighted by Book News, Inc., Portland, OR

Based on the Tenth International Basement Tectonics Conference held at the University of Minnesota-Duluth in August 1992, this volume contains 19 papers, 13 of which focus on the Middle Proterozoic Midcontinent Rift. An introductory essay discussing the Middle Proterozoic to Cambrian rifting in central North America is followed by contributions addressing topics including the Midcontinent Rift in Michigan and Minnesota, the Port Coldwell veins of northern Ontario, and petrography and sedimentation in the western Lake Superior region. The last five papers deal with the pre-Mount Simon basins of Ohio, the English Graben and the newly proposed East Continent Rift Complex, the Reelfoot Rift/Rough Creek Graben in the evolution of the Illinois Basin, and the A-type sheet granites in the Oklahoma Aulacogen of Cambrian age. Bandw illustrations. Annotation copyrighted by Book News, Inc., Portland, OR

"In this sequel to the award winning "Talking Rocks" an earth scientist and an Ojibwe elder travel across Minnesota exploring the ancient rocks that make up a large part of that state. As the geologist describes how these rocks formed and brings to life the ancient worlds they created, the elder, through Native American stories, oral history, culture, and science illustrates how his people had an intimate understand of, and respect for, these ancient rocks and the land they gave shape to. Traveling from northeastern to southwestern Minnesota, some of the diverse topics they discuss are the nature of science, holistic geology, l mining, science and spirituality, and the legacy of the fur trade. Ancient Earth and the First Ancestors not only tells a fascinating story that spans billions of years, but is also a wonderful chronicle of two people from different cultural and scientific heritages learning to understand, appreciate, and see the value and importance in each other's way of viewing this land the planet we all call home."--Pub. desc.

This work examines the archaeological record of copper mining in the Lake Superior area.

Published by the American Geophysical Union as part of the Field Trip Guidebooks Series, Volume 203. Rocks that once constituted parts of the southeastern margin of Proterozoic North America are widely exposed in internal and external massifs throughout the Appalachian orogen (Rodgers, 1987; Reed, 1987). The oldest rocks exposed in these massifs are plutonic rocks and gneisses emplaced or metamorphosed during the 1000 to 1100 Ma Grenville orogeny. These Middle Proterozoic basement rocks are unconformably overlain by metasedimentary and metavolcanic sequences of Late Proterozoic age that record rifting events during the early stages of opening of Iapetus, the early Paleozoic ancestor of the present Atlantic Ocean. Both basement and cover rocks are exposed in the Blue Ridge anticlinorium, a major tectonic element that extends for more than 300 km northeastward from near Lynchburg, Virginia to the vicinity of Carlisle, Pennsylvania (Figure 1). Proterozoic rocks in the core of the anticlinorium are stratigraphically overlain by lower Paleozoic rocks. On the northwest limb of the anticlinorium these strata include a basal Cambrian clastic sequence (the Chilhowee Group), a Cambrian through Middle Ordovician miogeoclinal sequence consisting of carbonates and mature clastics, and various shallow marine to terrestrial strata of Late Ordovician to Carboniferous age. Collectively they constitute the classic sequence of the Valley and Ridge province of the central Appalachians.

Impact cratering is an important geological process on all solid planetary bodies, and, in the case of Earth, may have had major climatic and biological effects. Most terrestrial impact craters have been erased or modified beyond recognition. However, major impacts throw ejecta over large areas of the Earth's surface. Recognition of these impact ejecta layers can help fill in the gaps in the terrestrial cratering record and at the same time provide direct correlation between major impacts and other geological events, such as climatic changes and mass extinctions. This book provides the first summary of known distal impact ejecta layers