@article {1029,
	title = {Cross-formational flow and salinity sources inferred from a combined study of helium concentrations, isotopic ratios, and major elements in the Marshall aquifer, southern Michigan},
	journal = {Geochemistry Geophysics Geosystems},
	volume = {6},
	year = {2005},
	note = {973vwTimes Cited:18Cited References Count:63},
	month = {Oct 8},
	abstract = {Helium data and major ion chemistry are presented for the shallow Marshall aquifer in southern Michigan. This data set is subsequently analyzed in conjunction with major element data sets from deeper and shallower water levels previously collected in this area. He excesses and isotopic ratios suggest the presence of tritiogenic He-3 in young waters in the Marshall aquifer. He excesses in old groundwater samples are mostly of crustal origin although the presence of a significant mantle He component in some samples cannot be ruled out. He excesses in the Marshall aquifer are unusually high for such shallow depths ( <= 300 m) and reach over two and three orders of magnitude above those of air- saturated water ( ASW) for He-3 and He-4, respectively. He isotopes require a source external to the aquifer, partly supplied by underlying formations within the sedimentary sequence, partly from the crystalline basement. Calibration of He concentrations observed in the Marshall aquifer requires He fluxes of 1 x 10(-13) and 1.6 x 10(-6) cm(3) STP cm(-2) yr(-1) for He-3 and He-4, respectively. These He fluxes are far greater than those reported in other sedimentary basins around the world ( e. g., Paris Basin, Gulf Coast Basin) at similar and far greater depths. Such high He fluxes present at such shallow depths within the Michigan Basin strongly suggest the presence of a dominant vertical water flow component and further indicate that impact of recharge water at depth is minor. Upward cross- formational flow is also likely responsible for the extremely high salinities present in the shallow subsurface of the Michigan Basin. The observed positive correlation between helium and bromide strongly suggests that these two very distinct conservative tracers both originate at greater depths and further suggests that advection is the dominant transport mechanism within the basin. The occurrence of large- scale cross- formational flow is also consistent with the evolution displayed by the major ion chemistry throughout most of the sedimentary sequence, indicating that solutes from shallow levels carry the signature of deep formation brines.},
	issn = {1525-2027},
	doi = {10.1029/2005GC001010},
	author = {Ma, L. and Castro, M. C. and Hall, C. M. and Walter, L. M.}
}
@article {1993,
	title = {Long term calibration of the Noble gas temperature system in a shallow unconfined Pleistocene aquifer},
	journal = {Eos Trans. AGU Fall Meeting Supplement},
	volume = {86},
	year = {2005},
	note = {id: 438},
	month = {2005},
	author = {Hall, C. M. and Castro, M. C. and Lohmann, K. C. and Ma, L.}
}
@article {1992,
	title = {Noble gases and stable isotopes in a shallow aquifer in southern Michigan: Implications for noble gas paleotemperature reconstructions for cool climates},
	journal = {Geophysical Research Letters},
	volume = {32},
	year = {2005},
	note = {968qnTimes Cited:26
Cited References Count:14
},
	month = {Sep 22},
	pages = {1-4},
	abstract = {Noble gas data from the Glacial Drift, the shallowest aquifer in southern Michigan confirm findings by Ma et al. (2004) that modern noble gas temperatures (NGTs) are systematically below the current mean annual air temperature (MAAT) which, in turn, is similar to the ground temperature of these recharge waters. By tracking noble gas concentrations as well as stable isotope ratios through an autumn, winter, spring and into summer, we show that although water in this aquifer is modern, noble gases do not track the atmosphere on a short time scale. Specifically, excess He-3 and He-4 indicate that the gas environment at the water table is integrating conditions over years or decades rather than weeks or months. Our results are interpreted using various NGT interpretational models and possible mechanisms for the production of low apparent NGTs are discussed.},
	keywords = {water},
	isbn = {0094-8276},
	doi = {10.1029/2005GL023582},
	url = {http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2\&amp;SrcAuth=Alerting\&amp;SrcApp=Alerting\&amp;DestApp=WOS\&amp;DestLinkType=FullRecord;UT=WOS:000232177300004},
	author = {Hall, C. M. and Castro, M. C. and Lohmann, K. C. and Ma, L.}
}
@article {1030,
	title = {Unusually high helium fluxes in the shallow Marshall aquifer in southern Michigan: implications for cross-formational flow and salinity sources},
	journal = {Eos Trans. AGU Fall Meeting Supplement},
	volume = {86},
	year = {2005},
	note = {id: 437},
	author = {Ma, L. and Castro, M. C. and Hall, C. M. and Walter, L. M.}
}
@article {1028,
	title = {A late Pleistocene-Holocene noble gas paleotemperature record in southern Michigan},
	journal = {Geophysical Research Letters},
	volume = {31},
	year = {2004},
	note = {881pcTimes Cited:31Cited References Count:24},
	month = {Dec 9},
	pages = {1-24},
	abstract = {Noble gas temperatures (NGTs) and C-14 derived ages in groundwaters of the Michigan Basin reveal a ground temperature of similar to1degreesC toward the end of the Last Glacial Maximum (LGM) suggesting that groundwater recharge occurred under the Laurentide Ice Sheet (LIS) cover. In addition to the general warming observed since the LGM, the NGT record indicates an abrupt warming event between similar to12.8 and 11.1 kyrs BP, correlative to the Bolling-Allerod (BOA) warm phases. Ice-sheet-linked changes in freshwater delivery to the North Atlantic, together with changes in the North Atlantic Deep Water (NADW) circulation are possible causes of such abrupt climate shifts in northeastern US. Pleistocene waters yielding the lowest NGTs have the highest delta(18)O and deltaD values, suggesting an atmospheric circulation pattern distinct from today, with a stronger moisture component from the Gulf of Mexico, possibly due to the presence of the LIS which weakened the Pacific westerly flow.},
	issn = {0094-8276},
	doi = {10.1029/2004GL021766  },
	author = {Ma, L. and Castro, M. C. and Hall, C. M.}
}
