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outside the province where the primary standardbiozonation is established, introducing a correlationuncertainty into time scale calibration. Inthe Early Jurassic, an uncertainty of approximatelyone standard ammonoid substage is demonstratedusing the UA method, if using a NorthAmerican U-Pb date requires correlation withthe northwest European zonation. The resolutionof the time scale was significantly improved forthe Ordovician and Silurian by employing constrainedoptimization to construct a global sequenceof graptolite bioevents. Interpolation betweenthe available U-Pb dates is possible byscaling using the assumption of near-constantsedimentation rate in pelagic facies. Future usesof quantitative biostratigraphymay include exploitationof large paleontologic databases(e.g.the Paleobiology Database) and contributionto the generation of dynamic, interactive geologictime scales.2008040503原 乌 氏 观 点 到 新 乌 氏 观 点 :“ 层 叠 地 层 学 ” 的复 兴 = Eo-Ulrichian to Neo-Ulrichianviews:The renaissance of “layer-cake stratigraphy”.( 英 文 ). Brett C E; McLaughlin P I; BairdG C. Stratigraphy, 2007, 4(2/3): 201-215Classical notions of “layer-cake stratigraphy”have been denigrated as representing an antiquated“Neptunian” view of the geologic recordwith the American paleontologist-stratigrapherE.O. Ulrich vilified as its quintessential advocate.Some of the extreme“layer-cake” interpretationsof E.O. Ulrich are demonstrably incorrect, especiallywhere applied in marginal marine and terrestrialsettings. However, close scrutiny of Ulrich’swork suggests that the bulk was correctand demonstrated considerable insight for thetime. Subsequent development of facies conceptsrevolutionized geologists’ view of timespacerelationships in stratigraphy, but ratherthan focusing on facies patterns within the establishedstratigraphic (layer-cake) frameworksmany geologists in North America came to viewstrata as parts of diachronous facies mosaics.Recent advances in the development of eventand sequence stratigraphic paradigms are beginningto swing the pendulum back the other way.Possible causes of “layer-cake” patterns are numerousand varied, including: (1) parallelism ofdepositional strike and outcrop belts, especiallyin foreland basins, (2) very widespread environmentalbelts developed in low-relief cratonicareas, (3) time-averaging homogenizes facies toa limited extent, resulting in a very subtle signatureof lateral change, (4) condensed beds(hardgrounds, bone beds, ironstones, etc.) oftenform in responses to extrabasinal forces, thusthey cross-cut facies, and (5) large events (i.e.hurricanes, floods, tsunamis, eruptions, etc.) are“over represented” in the rock record. A revised(“Neo-Ulrichian”) layer-cake paradigm carriesmany of the original correct empirical observationsof pattern, noted by Ulrich, recast in termsof event and sequence stratigraphy.2008040504旋 回 地 层 学 和 天 文 年 代 表 = Cyclostratigraphyand the Astronomical Time Scale. ( 英 文 ). HinnovL A; Ogg J G. Stratigraphy, 2007, 4(2/3):239-251An important innovation in the InternationalGeologic Time Scale 2004 is the use of astronomicallyforced stratigraphy, or cyclostratigraphy,to define geologic time over 0 to 23.03 Ma,much of it at an unprecedented resolution of 0.02myr. In addition,‘floating’ astronomical timescales with 0.10 to 0.40 myr resolution are definedfor entire epochs and stages in the Paleogeneand all three Mesozoic periods. Some ofthese calibrations use a new astronomical modelwith an hypothesized high accuracy over 0-250Ma. These accomplishments have motivated theInternational Commission on Stratigraphy tocomplete a continuous Astronomical Time Scale(‘ATS’) for the past 250 Ma, and to initiate acoordinated prospecting for astronomical-likesignals in Paleozoic cyclostratigraphy. Astronomicallycalibrated geologic time with a 0.02 to0.40 myr resolution is a major breakthrough forthe geosciences. Chronostratigraphy betweenwidely spaced horizons dated with highprecisionradioisotope geochronology sufferstotal loss in precision and accuracy; a continuousATS between horizons can restore this hard-wonprecision and accuracy. Consequently, estimatesof rates and magnitudes for a wide range ofEarth system processes that can be examinedonly in the context of Earth history, e.g., paleoclimatology,geochronology, geodynamics,structural geology, geochemical cycles and bioticevolution, will be improved up to an orderof magnitude over what is possible today.2008040505过 去 的 将 来 : 数 字 时 代 的 地 质 年 代 = The futureof the past: Geological time in the digitalage. ( 英 文 ). Van Couvering J A; Ogg J G.Stratigraphy, 2007, 4(2/3): 253-257The advances in information handling that aremade possible by digitization force us to considerwhether the existing procedures for updatingand using the standard Geological TimeScale, based on printed books, may be obsolete.Not only does print publishing require expensiveinvestment, but the publication process imposeslimits on participation and distribution, as wellas setting a deadline on improvement. In addition,digitization means that the way we use theinformation is no longer limited to what can be151