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[1] Borehole-based reconstructions of ground surface temperature (GST) have been widely used as indicators of paleoclimate. These reconstructions assume that heat transport within the subsurface is conductive. Climatic interpretations of GST reconstructions also assume that GST is strongly coupled to surface air temperature (SAT) on timescales of decades and longer. We examine these two assumptions using records of SAT and subsurface temperature time series from Fargo, North Dakota; Prague, Czech Republic; Cape Henlopen State Park, Delaware; and Cape Hatteras National Seashore, North Carolina. The characteristics of downward propagating annual temperature signals at each site clearly indicate that heat transport can be described as one-dimensional conduction in a homogeneous medium. Extrapolations of subsurface observations to the ground surface yield estimates of annual GST signals and allow comparisons to annual SAT signals. All annual GST signals are modestly attenuated and negligibly phase shifted relative to SAT. The four sites collectively demonstrate that differences between annual GST and SAT signals arise in both summer and winter seasons, in amounts dependent on the climatic setting of each site.

assignments can be evaluated by comparison with radiochemical age assignments and late Pleistocene temperature histories inferred from one or more paleoclimatic records. The kinetic model ages can also be evaluated within the constraints of both eustatic sea-level and isotopic ice-volume records. Age assignments for many of the late Pleistocene localities investigated in this work are in the range of 100,000 to 140,000 years and these localities are correlated with the early part of Stage 5 of the marine isotopic record (Shackleton and Opdyke, 1973). These age assignments are, in all cases, consistent with the radiometric age assignments for" the calibration localities. Samples from high terraces on San Nicolas Island, Palos Verdes Hills, and San Joaquin Hills, and from the San Pedro Sand have kinetic model ages of between 350,000 and 550,000 years and appear correlative with all or part of Stages 9 and II of the marine isotopic record. Three low terrace localities in southern California have yielded samples with ages in the range 200,000 to 250,000 years (correlative with Stage 7 of the marine isotopic record), though previous interpretations of these localities had implied correlation with localities that are sho~~to be younger. Some of these older samples may have been reworked into younger deposits. Localities with late Stage 5 (80,000 to 100,000 yrs.) ages are found at Santa Cruz, California and on Point Loma, San Diego, California (the Bird Rock Terrace). Both radiometric and geologic information are consistent with these age assignments. Samples from Cape Blanco, Oregon, appear to be either lateor post-Stage 5 in age; samples from Goleta, California are definitely post-Stage 5 in age, and appear to be approximately 40,000 years in age. iii Several of these age assignments permit revisions in the interpretation of pre-existing paleoecologic data. In addition, long-term average uplift rates for each dated locality can be estimated: most of the Stage 5 localities reported herein have apparent uplift rates between .1 and .3 meters/lOOO yrs. Uplift rates of .15 to .75 meters/IOOO yrs. are inferred from the results for San Nicolas Island and the Palos Verdes Hills. Quite. rapid uplift rates of 1.5 to 2.75 meters/IOOO yrs. for Goleta and Cape Blanco are also inferred from our results.

[1] Inversions of borehole temperature profiles that reconstruct past ground surface temperature (GST) changes have been used to estimate historical changes in surface air temperature (SAT). Paleoclimatic interpretations of GST reconstructions are based on the assumption that GST and SAT changes are closely coupled over decades, centuries, and longer. This assumption has been the subject of some debate because of known differences between GST and SAT at timescales of hours, days, seasons, and years. We investigate GST and SAT relationships on daily, seasonal, and annual timescales to identify and characterize the principal meteorological changes that lead to short-term differences between GST and SAT and consider the effects of those differences on coupling between the two temperatures over much longer time periods. We use observational SAT and subsurface data from Fargo, North Dakota; Prague, Czech Republic; Cape Henlopen State Park, Delaware; and Cape Hatteras National Seashore, North Carolina. These records comprise intradaily observations that span parts of one or two decades. We compare subsurface temperature observations to calculations from a conductive subsurface model driven with daily SAT as the surface boundary condition and show that daily differences exist between observed and modeled subsurface temperatures. We also analyze year-to-year spectral decompositions of daily SAT and subsurface temperature time series and show that dissimilarities between mean annual GST and SAT are attributable to differences in annual amplitudes of the two temperature signals. The seasonal partitioning of these amplitude differences varies from year to year and from site to site, responding to variable evapotranspiration and cryogenic effects. Variable yearto-year differences between mean annual GST and SAT are closely estimated using results from a multivariate regression model that associates the partial influences of seasonal meteorological conditions with the attenuation of annual GST amplitudes.

Uranium series coral ages for emergent units from the passive continental margin US Atlantic Coastal Plain (ACP) suggest sea level above present levels at the end of marine oxygen isotope stage (MIS) 5, contradicting age-elevation relations based on marine isotopic or coral reef models of ice equivalent sea level. We have reexamined this problem by obtaining high precision 230 Th/ 238 U and 231 Pa/ 235 U thermal ionization mass spectrometric ages for recently collected and carefully cleaned ACP corals, many in situ. We recognize samples that show no evidence for diagenesis on the basis of uranium isotopic composition and age concordance. Combining new and earlier data, among those ages close to or within the age range of MIS 5, over 85% cluster between 65 and 85 ka BP. Of the corals that we have analyzed, those that show the least evidence for diagenesis on the basis of uranium isotopic composition and age concordance have ages between 80 and 85 ka BP, consistent with a MIS 5a correlation. The units from which these samples have been collected are all emergent and have elevations within B3-5 m of those few units where early stage 5 (B125,000 ka BP) coral ages have been obtained. The ACP appears to record an unusual history of relative sea level throughout MIS 5, a history that is also apparent in the dated coral record for Bermuda. We speculate that this history is related to the regional (near-to intermediate-field) effects of ancestral Laurentide Ice sheets on last interglacial shorelines of the western North Atlantic.

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Isoleucine, one of several amino acids isolated from a suite of welldated deep-sea cores, shows a progressive increase in the degree of racemization with the age of the sediment. Amino acids in sediments show an initial rate of racemization almost an order of magnitude faster than the rate observed for free amino acids at a comparable pH and temperature. The observed kinetics depend on a variety of diagenetic processes, but it appears that the ratio of alloisoleucine to isoleucine is a reliable indicator of age for samples less than 400,000 years old; for older samples the results are more ambiguous. Isoleucine is racemic in samples older than about 15 x 10(6) years.