NICE* GEO-GROUP

About NICE Geo-group

Participants and contacts

Images

Publications pertaining to NICE Geo-group

ABOUT THE NICE GEO-GROUP

Newly compiled gravity and aeromagnetic data sets (see images), combined with recent geologic and geochronologic investigations, have provided striking new perspectives on the Precambrian structure and evolution of the cratonic interior beneath the north-central United States. In response, two informal workshops were held at the Minnesota Geological Survey, one in January of 2005 and one in January 2006, to revise the geologic framework for the basement rocks of the north-central region. Workshop participants have been actively involved in Precambrian studies in the north-central United States, and included representatives of the U. S. Geological Survey, state geologic surveys, and academic institutions. A generalized tectonic map has been produced, as has a preliminary geologic map of Precambrian geology (see images). The preliminary geologic map, as well as papers by some workshop participants, was presented at the 2005 meeting of North-Central Section of the Geological Society of America (see publications). An informal workshop at the regional GSA 2005 meeting revealed a high level of interest for Precambrian studies in the north-central United States, especially with regard to how these may relate to the EarthScope initiative. A working group was subsequently formed, and its focus is summed up by its acronym, NICE (Northern Interior Continental Evolution). The objective of this group is to produce a comprehensive and up-to-date model of crustal structure and evolution for the cratonic interior of the northern United States. Current plans for publication include a short article in a professional society newsletter, and a series of papers in a special issue of the Journal "Precambrian Research".

The activities of the NICE geo-group are relevant to the EarthScope initiative, particularly its USARRAY component. The success of the USARRAY program, which aims to seismically resolve lithospheric and deep earth structure, depends to a significant degree on the geologic and tectonic context of a given region. The comprehensive geologic model that is being produced by the NICE geo-group will provide this context for the north-central United States, and should provide testable hypotheses for the USARRAY experiments. Of particular importance is the southward transition from Archean to Paleoproterozoic lithosphere in the cratonic interior, and the nature of the Paleoproteozoic orogens that produced this transition. In comparison to the western United States, relatively little tectonism has occurred in the cratonic interior since middle Proterozoic time, and provides a uniquely unaltered perspective into Precambrian evolution of the lithosphere.

If you have any questions or comments please contact either:

Val Chandler, Minnesota Geological Survey (chand004@umn.edu)
or
Daniel Holm, Kent State University (dholm@kent.edu)

REFERENCES PERTINENT TO NICE GEO-GROUP

CANNON, W. F., SCHULZ, K. J , DANIELS, D. L. , ANDERSON, R. R., CHANDLER, V. W., HOLM, D. K., SCHNEIDER, D. A., AND VAN SCHMUS, W. R. 2005, GEOLOGY OF PRECAMBRIAN BASEMENT ROCKS IN IOWA AND THE SOUTHERN PARTS OF WISCONSIN AND MINNESOTA (abs.), 51st annual Meeting of the Institute on Lake Superior Geology, Proceedings and Abstracts, p. 10-11.

CANNON, W. F., SCHULZ, K. J , DANIELS, D. L. , ANDERSON, R. R., CHANDLER, V. W., HOLM, D. K., SCHNEIDER, D. A., AND VAN SCHMUS, W. R. 2005, GEOLOGY OF PRECAMBRIAN BASEMENT ROCKS IN IOWA AND THE SOUTHERN PARTS OF WISCONSIN AND MINNESOTA (abs.), 39th Annual Meeting North-Central Section, Geological Society of America, Abstracts with Program, p. 29.

CHANDLER, V. W., BOERBOOM, T. J., AND JIRSA, M. A., 2005, RECENT INVESTIGATIONS OF THE PENOKEAN OROGEN IN MINNESOTA: A CASE FOR INDENTER TECTONICS ALONG A PROMONTORY-REENTRANT MARGIN, (abs.), 39th Annual Meeting North-Central Section, Geological Society of America, Abstracts with Program, p. 4.

HOLM, D. K., BOERBOOM, T. J., AND SCHNEIDER, D. A., 2005, THE MCGRATH GNEISS DOME AND MALMO STRUCTURAL DISCONTINUITY IN E-C MINNESOTA: LINKED EXHUMATION STRUCTURES FORMED DURING COLLAPSE OF THE WESTERN PENOKEAN OROGEN, (abs.), 39th Annual Meeting North-Central Section, Geological Society of America, Abstracts with Program, p. 4.

HOLM, D. K, VANSCHMUS, W.R., MACNEILL, L.C., BOERBOOM, T. J., SCHWEITZER, D., AND SCHNEIDER, D. A., 2005, U-PB ZIRCON GEOCHRONOLOGY OF PALEOPROTEROZOIC PLUTONS FROM THE NORTHERN MIDCONTINENT, USA: EVIDENCE FOR SUBDUCTION FLIP AND CONTINUED CONVERGENCE AFTER GEON 18 PENOKEAN OROGENESIS, Geological Society of America Bulletin: Vol. 117, No. 3, pp. 259-275.

LOOFBORO, J., HOLM, D. K., AND SCHNEIDER, D. A., 2005, IMPLICATIONS OF DETRITAL AND METAMORPHIC MONAZITE AGE DATA FROM PROTEROZOIC QUARTZITES AND BASEMENT IN CENTRAL WISCONSIN, (abs.), 39th Annual Meeting North-Central Section, Geological Society of America, Abstracts with Program, p. 5.

SCHULZ, K. J., 2005, AGE CONSTRAINTS ON THE PALEOPROTEROZOIC PEMBINE OPHIOLITE-ISLAND ARC COMPLEX AND IMPLICATIONS FOR THE EVOLUTION OF THE PENOKEAN OROGEN, (abs.), 39th Annual Meeting North-Central Section, Geological Society of America, Abstracts with Program, p. 4.

SCHNEIDER, D.A., HOLM, D.K., AND LOOFBORO, J., 2005, NEWLY RECOGNIZED PALEOPROTEROZOIC MAFIC MAGMATISM, CENTRAL PENOKEAN OROGEN (WISCONSIN) , (abs.), 39th Annual Meeting North-Central Section, Geological Society of America, Abstracts with Program, p. 4-5.

VAN SCHMUS, W.R., 2005, ARCHEAN-PALEOPROTEROZOIC TRANSITION IN THE NORTHERN UNITED STATES (abs.), 39th Annual Meeting North-Central Section, Geological Society of America, Abstracts with Program, p. 4.