O Cretáceo inferior é caracterizado por mudanças drásticas em todos os envelopes terrestres, envolvendo desde variações geodinâmicas a importantes mudanças paleoclimáticas. Entretanto, há poucos registros desses eventos no hemisfério sul, sendo o DSDP-511 o principal deles. Com objetivo de gerar melhores vínculos temporais para os registros do Cretáceo Inferior no hemisfério sul, foram realizados estudos paleomagnéticos e de magnetismo ambiental em alta resolução espacial em uma secção do sítio DSDP-511 (núcleos 58 e 59), a qual corresponde ao intervalo entre 508,77 a 523,94 mbsf (meters below sea floor) e abrange os estágios Barremiano e Aptiano. A compreensão dos eventos paleoclimáticos neste sítio não é trivial, uma vez que, além de ambiguidade nas idades inferidas pela bioestratigrafia, apenas parte do evento de anoxia oceânica OAE 1a está registrada devido a uma lacuna de amostragem. Foram identificados dois principais portadores magnéticos através da análise de curvas de aquisição e desmagnetização de magnetização remanente anisterética (ARM) e magnetização remanente isotérmica (IRM). O mineral de baixa corecividade é a magnetita, confirmada a partir da desmagnetização de IRM triaxial. Sua origem é provavelmente detrítica. O portador de alta coercividade foi interpretado como hematita. A contribuição relativa dos portadores magnéticos apresentou uma variação acentuada no intervalo entre 512 e 514 mbsf, sendo manifestada através de um pico em todos os parâmetros de magnetismo ambiental. Esta variação está associada também à maior concentração de minerais magnéticos neste intervalo e coincide com um marcado aumento na temperatura da superfície dos oceanos. Após desmagnetização progressiva e identificação da componente magnética característica foram definidas duas zonas de polaridade normal e uma zona de polaridade reversa (518,9 e 518,16 mbsf). Além disso, foi definida uma zona discreta de polaridade reversa em 509,20 mbsf. Os resultados encontrados apresentam diferenças significativas quando comparadas com estudos anteriores no mesmo testemunho. Uma datação Re-Os em folhelhos negros de 125,3 ± 2,2 Ma entre 519,01 e 519,40 mbsf foi obtida recentemente e forneceu um vínculo absoluto de idade para o intervalo estudado. O padrão de reversões encontrado foi compatível com a presença dos chrons M0r e ISEA. O modelo de idades proposto permite reposicionar o evento OAE 1a entre as profundidades 513,5 a 518 mbsf, incluindo a parte não recuperada do testemunho. Esta interpretação também compatível com dados de TOC e de 13C obtidos recentemente por outros autores. / The lower Cretaceous is characterized by drastic changes in the Earth, from geodynamic variations to important paleoclimatic changes. However, there are few records of these events in the southern hemisphere, the DSDP-511 being the most comprehensive one. In order to provide better temporal constraints for the lower Cretaceous records in the southern hemisphere, paleomagnetic and high-resolution environmental magnetism studies were performed in a section of the DSDP-511 site (cores 58 and 59), which corresponds to the interval between 508.77 to 523.94 mbsf (meters below sea floor) and covers the Barremian and Aptian stages. The correct assessment of paleoclimatic events at this site is not trivial because, in addition to the ambiguity at the ages inferred by biostratigraphy, only part of the OAE 1a (oceanic anoxic event) was recovered. Two main magnetic carriers were identified through the analysis of acquisition and demagnetization of anhysteretic remanent magnetization (ARM) and isothermal remanent magnetization (IRM) curves. The low coercivity mineral is magnetite, as attested by triaxial IRM demagnetization. Its origin is likely detrital. The high coercivity carrier was interpreted as hematite. The relative contribution of magnetic carriers has a strong variation in the interval between 512 and 514 mbsf, being manifested by a peak in all parameters of environmental magnetism. This variation is also associated with the higher concentration of magnetic minerals and coincides with a marked increase in the sea surface temperature in this interval. After stepwise demagnetization and identification of the characteristic magnetic component, two zones of normal polarity and a zone of reverse polarity (518.9 and 518.16 mbsf) were defined. In addition, a discrete zone of reverse polarity was defined at 509.20 mbsf. The results obtained present significant differences when compared with previous studies in the same core. A Re-Os dating on black shales of 125.3 ± 2.2 Ma between 519.01 and 519.40 mbsf was obtained recently and provided an absolute constraint onto which the polarity zones could be matched. The pattern of reversions found is compatible with the presence of chrons M0r and ISEA. The proposed age model allows repositioning the OAE 1a event between depths 513.5 to 518 mbsf in the core and overlap the unrecovered part. This interpretation is also compatible with TOC and 13C data recently obtained by other authors.

The Canyon Range Formation (informal new name), formerly mapped as the Indianola Group within the Canyon Range, is divisible into two distinct, mappable units, A and B. Unit A is nearly all conglomerate strata, and conglomerate texture and sedimentary structures suggest an alluvial fan depositional environment. Precambrian and basal Cambrian quartzite clasts represent the erosional debris from the allochthonous Canyon Range thrust. Unit B is composed of interbedded fluvial sandstone and conglomerates with lacustrine limestones, commonly micritic and/or oncolitic. Conglomerate clasts indicate a Paleozoic carbonate provenance. Unit A, previously mapped as the Indianola, underlies Unit B and correlates with the Price River-lower North Horn Formations of the Pavant Range and Long Ridge. Marginal paleontologic and stratigraphic indicators suggest Unit B to be equivalent to the Paleocene-Eocene North Horn and Flagstaff Formations rather than the Cretaceous Indianola Group. Stratigraphic and structural relationships indicate the last major phase of "Sevier" thrusting ended by Price River (?) time.

Current mining operators in the Athabasca oil sands deposit of Alberta, Canada have made commitments to zero discharge of oil sands process-affected waste materials (OSPM) from the mine site and rehabilitation of mined lands to a pre-mining state. As part of aquatic reclamation efforts, experimental test sites that contain a range of OSPM (solid and liquid components) were constructed to monitor the evolution and viability of aquatic habitats used as disposal sinks for OSPM produced by mining activities. In the present study, stable isotopes of carbon, nitrogen and sulphur were used to gauge some of the potential effects of OSPM site construction methods on aquatic food webs. Carbon and nitrogen isotopic signatures of sediment, dissolved inorganic carbon, dissolved organic carbon, particulate organic matter, periphytic material, plants, plankton, aquatic invertebrates and fish were used to assess differences related to the naphthenic acid (NA) concentration in OSPM and reference sites. For statistical analyses, sites were grouped into low (0 to 4 mg/L), medium (4 to 15 mg/L) and high (> 15 mg/L) NA concentrations. There were no significant differences in food web area or food web length among the low, medium and high NA concentration sites. In most cases, sample carbon isotope analyses of low, medium and high NA concentration sites were not significantly different, suggesting food web carbon sources did not include significant contributions from OSPM materials at OSPM sites. Significant differences, however, were found in the sample nitrogen isotope signatures between low, medium and high NA concentration sites. Ammonia from OSPM is suggested to be the main contributor to &delta;¹⁵N enrichment. <br /><br /> To determine the potential effects of site construction and OSPM within experimental test sites, carbon and sulphur stable isotopes of water, plankton, aquatic invertebrates and fish were analyzed. With the exception of <em>Chaoborus</em> and <em>Haliplus</em>, all carbon isotope signatures were not significantly different in constructed and reference sites. Also with the exception of <em>Haliplus</em>, sulphur isotope values for aquatic organisms from constructed and reference sites were significantly different. Aquatic organisms and water samples from constructed sites built in, or close, to the boundary of Kcw clays typically had &delta;³⁴S < 0 ?. Coinciding with depleted &delta;³⁴S signatures found in these aquatic systems were elevated sulphate concentrations. The waters at experimental test sites are in direct contact with the soil materials that facilitate the accumulation of sulphates as a result of the oxidation of substrate sulphide minerals. In general the results of the study suggest that aquatic food web structure and function do not change with the introduction of OSPM. Shifts in isotopic signatures suggestive of changes in food web structure, however, do occur when site construction exposes Kcw clays in the substrate.

Current mining operators in the Athabasca oil sands deposit of Alberta, Canada have made commitments to zero discharge of oil sands process-affected waste materials (OSPM) from the mine site and rehabilitation of mined lands to a pre-mining state. As part of aquatic reclamation efforts, experimental test sites that contain a range of OSPM (solid and liquid components) were constructed to monitor the evolution and viability of aquatic habitats used as disposal sinks for OSPM produced by mining activities. In the present study, stable isotopes of carbon, nitrogen and sulphur were used to gauge some of the potential effects of OSPM site construction methods on aquatic food webs. Carbon and nitrogen isotopic signatures of sediment, dissolved inorganic carbon, dissolved organic carbon, particulate organic matter, periphytic material, plants, plankton, aquatic invertebrates and fish were used to assess differences related to the naphthenic acid (NA) concentration in OSPM and reference sites. For statistical analyses, sites were grouped into low (0 to 4 mg/L), medium (4 to 15 mg/L) and high (> 15 mg/L) NA concentrations. There were no significant differences in food web area or food web length among the low, medium and high NA concentration sites. In most cases, sample carbon isotope analyses of low, medium and high NA concentration sites were not significantly different, suggesting food web carbon sources did not include significant contributions from OSPM materials at OSPM sites. Significant differences, however, were found in the sample nitrogen isotope signatures between low, medium and high NA concentration sites. Ammonia from OSPM is suggested to be the main contributor to &delta;¹⁵N enrichment. <br /><br /> To determine the potential effects of site construction and OSPM within experimental test sites, carbon and sulphur stable isotopes of water, plankton, aquatic invertebrates and fish were analyzed. With the exception of <em>Chaoborus</em> and <em>Haliplus</em>, all carbon isotope signatures were not significantly different in constructed and reference sites. Also with the exception of <em>Haliplus</em>, sulphur isotope values for aquatic organisms from constructed and reference sites were significantly different. Aquatic organisms and water samples from constructed sites built in, or close, to the boundary of Kcw clays typically had &delta;³⁴S < 0 ?. Coinciding with depleted &delta;³⁴S signatures found in these aquatic systems were elevated sulphate concentrations. The waters at experimental test sites are in direct contact with the soil materials that facilitate the accumulation of sulphates as a result of the oxidation of substrate sulphide minerals. In general the results of the study suggest that aquatic food web structure and function do not change with the introduction of OSPM. Shifts in isotopic signatures suggestive of changes in food web structure, however, do occur when site construction exposes Kcw clays in the substrate.

An integrated micropaleontological, mineralogical and sequence stratigraphical investigation was carried out across the Cretaceous/Paleogene (K/P) boundary in the Haymana basin, Turkey. A 29.41 m thick boundary section consisting of limestones and marls was measured and 90 samples were analyzed. Biostratigraphic and chronostratigraphic works are based on the planktonic foraminifera. 64 planktonic species were identified and 5 biozones were established. The biozones are, in ascending order, Planoglobulina acervulinoides zone, Racemiguembelina fructicosa zone, Pseudoguembelina hariaensis zone for the Late Maastrichtian / Guembelitria cretacea (P0) zone and Parvulorugoglobigerina eugubina (P1a) zone for the Early Danian. In order to detect the mineralogical changes across the boundary bulk and clay minerals were analyzed using X-ray diffractometry (XRD). Calcite, quartz,feldspar and the clay minerals composed of smectite (montmorillonite) and chlorite are the main components of the rocks. A decrease in calcite and an increase in the detrital minerals (quartz, feldspar) and the clay minerals were detected in the boundary beds. In order to find out the depositional history of the area a detailed microfacies study was performed and 10 microfacies type were determined. The microfacies types defined correspond to slope to basin environment. Based on microfacies analyses, the sequence stratigraphic framework of the boundary beds was constructed. K/P boundary beds were recorded in the transition of transgressive systems tract to highstand systems tract, coinciding with a maximum flooding surface. These beds show a similar pattern with many other K/P boundary beds in different locations of the world indicating eustatic sealevel variations overprint the tectonic control in the basin.

The aim of this study is to establish the planktonic foraminiferal biozonation, to construct the sequence stratigraphical framework and to determine the foraminiferal response to sedimentary cyclicity in the sedimentary sequence spanning Upper Cretaceous-Paleocene in the Haymana basin (Central Anatolia, Turkey). In order to achieve this study, the stratigraphic section was measured from sedimentary sequence of the Haymana, Beyobasi and YeSilyurt formations. The sedimentary sequence is mainly characterized by flyschoidal sequence that is composed of alternating of siliciclastic and carbonate units. On the account of the detailed taxonomic study of planktonic foraminifers, the biostratigraphic framework was established for the Maastrichtian-Paleocene interval. The biozonation includes 7 zones / Pseudoguembelina hariaensis, P&amp / #945 / , P1, P2, P3, P4 and P5 zones. The Cretaceous-Paleogene (K/P) boundary was delinated between the samples HEA-105 and 106. In order to construct the sequence-stratigraphical framework, the A, B, C and D-type meter-scale cycles were identified. Based on the stacking patterns of them, six depositional sequences, six third and two second order cycles were determined. Third order cycles coincide with the Global Sea Level Change Curve. On the account of the conducted petrographic analysis sandstone, mudstone, marl, limestone and muddy-limestone lithofacies were recorded in the studied samples. In order to demostrate the response of foraminifers to cyclicity, quantitative analysis has been carried out by counting the individuals of planktonic, benthonic foraminifers and ostracods. The best response to sedimentary cyclicity was revealed from planktonic foraminifers. The average abundance of planktonic foraminifers increases in the transgressive systems tract and decreases in the highstand systems tract.

Whether a global greenhouse interval is a distinct or distant future, it is important to understand the dynamics of a greenhouse system. During such intervals the oceans, in the absence of sizeable polar ice caps, flood the continental shelf. The stratification and circulation of these epicontinental seas are open to debate, because there are no Recent analogs. The carbon and oxygen stable isotope record of fossil molluscan shell from epicontinental seas has the potential to reveal their stratification and seasonal cycles. Whether a global greenhouse interval is a distinct or distant future, it is important to understand the dynamics of a greenhouse system. During such intervals the oceans, in the absence of sizeable polar ice caps, flood the continental shelf. The stratification and circulation of these epicontinental seas are open to debate, because there are no Recent analogs. The carbon and oxygen stable isotope record of fossil molluscan shell from epicontinental seas has the potential to reveal their stratification and seasonal cycles. As a study sample, mollusks from the Baculites compressus and Baculites cuneatus biozones of the Western Interior Seaway of North America were collected from three locations: Kremmling, Colorado; Trask Ranch, South Dakota; Game Ranch, South Dakota. These fossils date to the Campanian (Late Cretaceous). Taxa include ammonites, bivalves, gastropods, and nautiloids. The first part of this investigation, described in Chapter 2, investigates the degree of alteration in these specimens. Elevated concentrations of minor elements such as magnesium and strontium reveal alteration from the original aragonite and/or calcite skeletons. Concentrations of these elements obtained by ICP-OES analysis are compared within several suites of specimens: mode of preservation, shell testing location, shell color, cementation, appearance under light microscope, and appearance under scanning electron microscope. Each of these suites tests a hypothesis about optimal shell preservation. Shell was found to be preserved best in shale rather than concretions, ammonite phragmacone rather than septa, opalescent specimens rather that nonopalescent ones, and uncemented shells rather than cemented shells, especially those with second-order versus first-order cement. Salinity and temperature values were derived for the organisms in the Western Interior Seaway: while bivalves produced unusually low temperatures, the others were reasonable for an inland sea. The second part of this study, described in Chapter 3, examines the isotopic record within exemplary mollusk shells, taken perpendicular to growth lines. The data for this investigation in sclerochronology documents the dominant isotopically enigmatic bottom-water habitat of the Inoceramus, the geochemical signature of the overlying water mass inhabited by Baculites, and short-term migrations between the two water masses in the nautiloid Eutrephoceras.

Sandstone units of the Upper Cretaceous San Miguel Formation in South Texas are wave-dominated deltaic sequences deposited during a major marine transgression. San Miguel sediments were deposited in the Maverick Basin within the Rio Grande Embayment. Cross sections and sandstone maps reveal that during deposition of the San Miguel Formation, the Maverick Basin consisted of two subbasins. A western subbasin received sediments from the northwest; the eastern subbasin received sediments from the north. Net-sandstone patterns show that the thickest parts of the sandstone bodies are generally strike oriented; where not eroded, updip sand-feeder systems are indicated by dip-aligned components. The San Miguel deltas vary considerably in morphology and make up a spectrum of wave-dominated delta types. Modern analogs of these San Miguel deltas include the Rhone, Nile, Sao Francisco, Brazos, Danube, Kelantan, and Grijalva deltas. Final sandstone geometries depended on three primary factors: (1) rate of sediment input, (2) wave energy, and (3) rate of sea-level change. Delta morphology was determined by all three factors, but the degree of reworking of deltaic sediments after delta abandonment was determined by wave energy and rate of transgression. The most common vertical sequences in the San Miguel coarsen upward from silt and clay to fine sand. Burrows are the dominant structures. The few primary structures are of small scale; large-scale cross beds are observed only in outcrop. Strandplain or barrier-island facies sequences, which prevail in most wave-dominated deltaic deposits, are incomplete in the San Miguel. In most places, only the lower shoreface is preserved. The upper parts of the sequences, which normally bear large-scale primary structures, were lost by marine reworking during subsequent transgressions. Intense burrowing destroyed any primary structures at the tops of the truncated sequences. Most of the San Miguel sandstones are arkoses. Cements include sparry and poikilotopic calcite, quartz overgrowths, feldspar overgrowths, illite rims, and kaolinite. The primary destroyers of porosity are the two types of calcite cement, which tend to completely cement the coarsest, best sorted, and originally most porous zones of the San Miguel vertical sequences. Zones of secondary porosity resulted from leaching of shell material, calcite cement, and feldspars. Laterally, the zones of either high secondary porosity or calcite cementation are unpredictable. / text

The Mural Limestone, located in the Mule Mountains to the northeast and southeast of Bisbee, Arizona provides an exceptional outcrop analog for time-equivalent productive reservoirs in the Albian Glen Rose patch-reef play of the Maverick Basin. The Mural Limestone is exposed in a number of folds and east-dipping fault blocks in the Grassy Hill and Paul Spur localities in the Mule Mountains and represents a remnant of a south-facing distally-steepened carbonate ramp that prograded into the Chihuahua Trough in Albian time. This study documents the detailed facies architecture and sequence stratigraphic setting of a multicyclic patch-reef and its associated ramp interior facies at the Paul Spur and Grassy Hill localities, respectively. Small mud-dominated coral-algal buildups (~5 m thick) and tabular biostromes (up to 1.5 m thick) consisting of rudist floatstones are common in the bedded ramp interior carbonates at the Grassy Hill locality in the Mule Mountains 10 km landward of the Paul Spur reef. Buildups in this area are flanked by weakly-cyclic and well-bedded skeletal mud- and grain-dominated packstones. At the Paul Spur locality, Mural facies consist of a 10-35 m thick patch-reef with four distinct reef communities: microbial-Microsolena framestone, algal-Actinastrea boundstone, branching coral-skeletal framestone and caprinid-requienid floatstone. Measured reef dimensions show a distinct windward-leeward margin with reef frame facies extending ~70 m from the margin and extensive leeward rudstone debris and grainstone shoal facies extending a distance of 870 m. Reef and backreef shoal facies exhibit low preserved porosity but petrographic analysis of backreef grainstones shows that primary porosity and permeability was present. These extensive reservoir-prone shoals may be a suitable reservoir target similar to flank rudstones and grainstones of the Maverick Basin reefs. Three aggradational to retrogradational cycles of reef growth are evident at the Paul Spur locality. Retrogradational stacking is consistent with that of time-equivalent Lower Glen Rose patch-reefs in the Maverick Basin of Texas, which suggests a eustatic driver for stratigraphic architecture along the Bisbee/Comanche shelf. Backstepping of reef frame facies in Cycle 3 is interpreted to be time-equivalent to patch-reef development at the Grassy Hill locality. / text

Three studies on Cordilleran foreland basin deposits in the western U.S.A. constitute this dissertation. These studies differ in scale, time and discipline. The first two studies include basin analysis, flexural modeling and detailed stratigraphic analysis of Upper Cretaceous depocenters and strata in the western U.S.A. The third study consists of detrital zircon U-Pb analysis (DZ U-Pb) and thermochronology, both zircon (U-Th)/He and apatite fission track (AFT), of Upper Jurassic to Upper Cretaceous foreland-basin conglomerates and sandstones. Five electronic supplementary files are a part of this dissertation and are available online; these include 3 raw data files (Appendix_A_raw_isopach_data.txt, Appendix_C_DZ_Data.xls, Appendix_C_UPb_apatite.xls), 1 oversized stratigraphic cross section (Appendix_B_figure_5.pdf), and 1 figure containing apatite U-Pb concordia plots (Appendix_C_Concordia.pdf). Appendix A. Subsidence in the retroarc foreland of the North American Cordillera in the western U.S.A. has been the focus of a great deal of research, and its transition from a flexural foreland basin, during the Late Jurassic and Early Cretaceous, to a dynamically subsided basin during the Late Cretaceous has been well documented. However, the exact timing of the flexural to dynamic transition is not well constrained, and the mechanism has been consistently debated. In order to address the timing, I produced new isopach maps from ~130 well log data points that cover much of Utah, Colorado, Wyoming and northern New Mexico, producing in the process, the most detailed isopach maps of the area. These isopach maps span the Turonian to mid-Campanian during the Late Cretaceous (~93–76 Ma). In conjunction with the isopach maps I flexurally modeled the Cordilleran foreland basin to identify when flexure can no longer account for the basin geometry and identified the flexural to dynamic transition to have occurred at 81 Ma. In addition, the dynamic subsidence at 81 Ma is compared to the position of the hypothesized Shatsky Oceanic Plateau and other proposed drivers of dynamic subsidence. I concluded that dynamic subsidence is likely caused by convection over the plunging nose of the Shatsky Oceanic Plateau. Appendix B. The second study is a detailed stratigraphic study of the Upper Cretaceous, (Campanian, ~76 Ma) Sego Sandstone Member of the Mesaverde Group in northwestern Colorado, an area where little research has been done on this formation. Its equivalent in the Book Cliffs area in eastern Utah has been rigorously documented and its distal progradation has been contrastingly interpreted as a result of active tectonism and shortening in the Cordilleran orogenic belt ~250 km to the west and to tectonic quiescence, flexural rebound in the thrust belt and reworking of proximal coarse grained deposits. I documented ~17 km of along depositional dip outcrops of the Sego Sandstone Member north of Rangely, Colorado. This documentation includes measured sections, paleocurrent analysis, a stratigraphic cross section, block diagrams outlining the evolution of environments of deposition through time, and paleogeographic maps correlating northwest Colorado with the Book Cliffs, Utah. The sequence stratigraphy of the Sego Sandstone Member in northwest Colorado is similar to that documented in the Book Cliffs area to the south-southwest, sharing three sequence boundaries. However, flood-tidal delta assemblages between fluvio-deltaic deposits that are present north of Rangely, Colorado are absent from the Book Cliffs area. These flood-tidal-delta assemblages are likely caused by a large scale avulsion event in the Rangely area that did not occur or was not preserved in the Book Cliffs area. In regards to tectonic models that explain distal progradation of the 76 Ma Sego Sandstone Member to be caused by tectonic quiescence and flexural rebound in the thrust belt, the first study shows that at 76 Ma, flexural processes were no longer dominant in the Cordilleran foreland, so it is inappropriate to apply models driven by flexure to the Sego Sandstone Member. Dynamic processes dominated the western U.S.A. during the Campanian, and flexural processes were subordinate. Appendix C. In order to test the tectonic vs. anti-tectonic basin-filling models for distal coarse foreland deposits mentioned above, the third study involves estimating lag times of Upper Jurassic to Upper Cretaceous conglomerates and sandstones in the Cordilleran foreland basin. Measuring lag time requires a good understanding of both the stratigraphic age of a deposit and the thermal history of sedimentary basin. To further constrain depositional age, I present twenty-two new detrital zircon U-Pb (DZ U-Pb) sample analyses, spanning Upper Jurassic to Upper Cretaceous stratigraphy in Utah, Colorado, Wyoming and South Dakota. Source exhumation ages can be measured using thermochronology. To identify a thermochronometer that measures source exhumation in the North America Cordillera, both zircon (U-Th)/He, on eleven samples, and apatite fission track (AFT) thermochronology, on eleven samples was performed. Typically, the youngest cooling age population in detrital thermochronologic analyses is considered to be a source exhumation signal; however, whether or not these apatites are exhumed apatites or derived from young magmatic and volcanic sources has been debated. To test this, I double dated the detrital AFT samples, targeting apatites with a young cooling age, using U-Pb thermochronology. Key findings are that the maximum depositional ages using DZ U-Pb match existing biostratigraphic and geochronologic age controls on basin stratigraphy. AFT is an effective thermochronometer for Lower to Upper Cretaceous foreland stratigraphy and indicates that source material was exhumed from >4–5 km depth in the Cordilleran orogenic belt between 118 and 66 Ma, and zircon (U-Th)/He suggests that it was exhumed from <8–9 km depth. Double dating apatites (with AFT and U-Pb) indicate that volcanic contamination is a significant issue; without having UPb dating of the same apatite grains, one cannot exclude the possibility that the youngest detrital AFT population is contaminated with significant amounts of volcanogenic apatite and does not represent source exhumation. AFT lag-times are 0 to 5 Myr with relatively steady-state to slightly increasing exhumation rates. We compare our data to orogenic wedge dynamics and subsidence histories; all data shows active shortening and rapid exhumation throughout the Cretaceous. Our lag-time measurements indicate exhumation rates of ~.9–>>1 km/Myr.