In assessing methane hydrate as a potential transitional energy source, quantification of in-place volumes of gas is a first step-and yet, global, regional, and even local estimates of gas volumes contained within hydrate are highly variable, including within the extensively-studied Gulf of Mexico (GoM) gas hydrate province. Here, we construct the first 3-D basin and hydrocarbon system model of the Terrebonne Basin (Walker Ridge protraction area, northern GoM) to estimate in-place resources contained as gas within hydrate, as well as to provide the first estimate of in-place resources contained within free gas accumulations in the basin. The resultant model-predicted 3-D distributions (and saturations) of hydrate are consistent with independent seismic interpretation and borehole observations. This study reveals both sedimentation-driven and salt diapir-driven gas hydrate recycling produce elevated hydrate saturations in the basin ("recycling" occurs when relative upward shifts of the gas hydrate stability zone (GHSZ) cause hydrate dissociation, generating buoyant free gas that may reaccumulate as higher-saturation hydrate at the new base of GHSZ). An important finding of this study (particularly given that, globally, the source of methane in marine hydrate systems tends to be poorly understood) is that microbial sources can explain most or all hydrate occurrences in Terrebonne Basin. We calculate that similar to 32 x 10(9) m(3) (similar to 1.1 x 10(12) ft(3)) of methane gas is trapped within hydrate accumulations throughout Terrebonne Basin, while nearly 2 x 10(9) m(3) (similar to 67 x 10(9) ft(3)) of methane occurs as free gas at high saturations within sandy reservoirs beneath the GHSZ and similar to 35 x 10(9) m(3) (similar to 1.2 x 10(12) ft(3)) occurs as free gas at low saturations within muddy units beneath the GHSZ. In total, our calibrated 3-D model predicts that nearly 70 x 10(9) m(3) (similar to 2.5 x 10(12) ft(3)) of microbial methane is trapped as gas hydrate and free gas in the Terrebonne Basin.

Analyzing how provenance signatures of tectonically complex ancient sedimentary basins vary between the outcrop and the subsurface provides a more complete sediment provenance history. The 500+-km- long outcrop belt of the Rocas Verdes and the Magallanes- Austral Basins in southern Patagonia and its subsurface to the east allow us to constrain relationships between longitudinal and transverse sediment sources feeding the basin. New detrital zircon U-Pb ages (n = 2558) from nine subsurface core samples from the Sprinreflection transect (50 degrees S, 71.5 degrees W- 69.5 degrees W) reveal the provenance of the basin's eastern subsurface extent and the influence that tectonic activity can have on sediment capture. Detrital zircon ages (n = 1068) were also collected from four outcrop Springhill Formation samples 140 km NW from the transect near Formation cores range from 159 to 157 Ma, which are older than correlative outcrop ages of 151- 148 Ma. MDAs from the Piedra Clavada and La Anita Formations range from 93.7 to 91.5 Ma and from 79.3 to 78.3 Ma, respectively, and overlap in age or are slightly younger than outcrop ages. The unimodal Late Jurassic age distribution from the Springhill Formation suggests that it almost exclusively was sourced by recycling of the underlying El Quemado Complex. Early- Middle Jurassic ages in the Early Cretaceous Piedra Clavada Formation samples suggest the basin was either sourcing from the North Patagonian Massif to the N-NE and from the Deseado Massif to the NE or recycling exhumed volcaniclastic sequences in the northern margin of the basin. By the Late Cretaceous, the basin fill was more locally sourced, as suggested by the muted abundance of Early- Middle Jurassic ages in La Anita Formation samples and a second mode of Late Jurassic- Early Cretaceous ages locally derived from recycling of the exhumed El Quemado Complex from the Patagonian fold- and- thrust belt. We suggest that the latitudinal and local transverse drainages that sourced the Magallanes- Austral Basin outcrop belt also fed the eastern, subsurface extent of the basin. Results of this work highlight the importance of using several types of provenance methods and a three- dimensional approach to study the erosional history of sedimentary basins.

U-Pb zircon geochronology and isotopic records have played an influential role in our understanding of convergent margin dynamics. Orogenic cyclicity models link tectonic regimes with magmatic isotopic signatures in advancing orogens, relating compressional regimes with evolved signatures and extension with juvenile signatures; however, such frameworks may not apply for retreating orogens, which commonly produce substantial crustal heterogeneities during backarc rifting and ocean spreading. We explore the Mesozoic to Cenozoic Patagonian Andes tectonic evolution, combining U-Pb zircon ages, bulk rock epsilon Nd, and new detrital zircon epsilon Hf from the retroarc basin to understand the associated magmatic arc evolution during retreat and advance of the margin. Our results reveal a protracted phase of isotopically juvenile magmatism between 150 and 80 Ma, which began during backarc extension and persisted long after the margin switched to a contractional regime. We propose that the prolonged juvenile isotopic trend started mainly due to trenchward migration of the arc during backarc extension (150-120 Ma) and persisted due to partial melting of underthrusted juvenile attenuated and oceanic crust during backarc basin closure (120-80 Ma). This interpretation implies that tectonic stress alone does not predict isotopic trends, and factors like assimilation or the composition of underthrusted crust are important controls on magmatic isotopic composition, especially in retreating and transitional orogens.

Global sedimentary hiatuses are well-documented in ancient pelagic sediment, and include Paleocene, Eocene-Oligocene boundary, and Miocene hiatuses. Less clear is the extent of these hiatuses in continental margin settings. Here, we test the hypothesis that global hiatuses evident in pelagic sections are also manifested in siliciclastic basins of continental margins globally. We choose to focus on the Eocene greenhouse to Oligocene icehouse transition, a period that is remarkable as the most profound climatic transition of the Cenozoic, and a period characterized by extreme cooling and expansion of polar ice, sea-level fall, and global changes to ocean circulation. We perform a comprehensive review of marine siliciclastic basin literature to produce a global inventory of Eocene-Oligocene unconformities. We find evidence for a prominent Eocene-Oligocene unconformity in sedimentary basins along the margins of every continent. The globally-widespread distribution of unconformities suggests global controls on their development. Furthermore, Eocene-Oligocene erosion surfaces are common in shelf settings, as well as in deep-water settings from slope to basin floor, indicating unconformity-generating processes across a wide range of water depths. Global sea-level fall may have driven subaerial shelf exposure and erosive down-slope processes including submarine canyon cutting and mass wasting. Meanwhile, the intensification of deep-ocean thermohaline currents potentially induced erosion of not only pelagic successions, but also of clastic successions. Overall, our documentation of globally-widespread Eocene-Oligocene unconformities suggests global controls, of which the extreme climatic and oceanographic changes of the greenhouse to icehouse transition seem particularly compelling.

The early Eocene (~ 56–48 million years ago) was marked by peak Cenozoic warmth and sea levels, high CO 2 , and largely ice-free conditions. This time has been described as a period of increased continental erosion and silicate weathering. However, these conclusions are based largely on geochemical investigation of marine mudstones and carbonates or study of intermontane Laramide basin settings. Here, we evaluate the marine coarse siliciclastic response to early Paleogene hothouse climatic and oceanographic conditions. We compile an inventory of documented sand-rich (turbidite) deep-marine depositional systems, recording 59 instances of early Eocene turbidite systems along nearly all continental margins despite globally-elevated sea levels. Sand-rich systems were widespread on active margins (42 instances), but also on passive margins (17 instances). Along passive margins, 13 of 17 early Eocene systems are associated with known Eocene-age fluvial systems, consistent with a fluvial clastic response to Paleogene warming. We suggest that deep-marine sedimentary basins preserve clastic records of early Eocene climatic extremes. We also suggest that in addition to control by eustasy and tectonism, climate-driven increases in sediment supply (e.g., drainage integration, global rainfall, denudation) may significantly contribute to the global distribution and volume of coarse-grained deep-marine deposition despite high sea level.

A high-resolution multibeam survey from a portion of the San Simeon Channel (offshore Morro Bay, California) captured a zone of recurring troughs and ridges adjacent to prominent submarine meander bends. Through an integrated study using surveying data, sediment core analysis, radiocarbon dating, and stable isotope measurements, we hypothesize that turbidity current event frequency was higher during the late Pleistocene than at present conditions. We speculate that the rise in sea-level following the Last Glacial Maximum sequestered sedimentation largely to the shelf during the Holocene. This work suggests that the occurrence of sediment gravity flows in this region, particularly away from any submarine channels, is appreciably lower than at times of continental shelf subaerial exposure.

Songliao Basin, the largest Mesozoic intracontinental nonmarine basin in eastern China, initiated during the latest Jurassic as a backarc extensional basin; rifting failed and thermal cooling controlled subsidence through the early Late Cretaceous. Integrating 2-D and 3D reflection seismic and borehole data with regional geological studies, we interpret sedimentary sequence and structural patterns of the Coniacian-Maastrichtian fill of Songliao Basin as defining a retroforeland basin system developed after 88 Ma (marked by the T11 unconformity in the basin), including (1) significant increase in the thickness of the Nenjiang Formation eastward towards orogenic highlands of the Zhangguangcai Range and the convergent continental margin; (2) a shift of detrital provenance in the basin from north to southeast; and (3) propagation of E-W shortened structures, increasing eastward in amplitude, frequency, and degree of inversion toward the orogen. During latest Cretaceous, foreland basin fill progressively deformed, as the foredeep evolved to a wedge-top tectonic setting, marked by the basin-wide T04 unconformity within the upper Nenjiang Formation at 81.6 Ma. Much of the basin was brought into the orogenic wedge and eroded by the end of the Cretaceous. Late Jurassic/Early Cretaceous backarc rifting of uncratonized basement comprised of accreted terranes likely facilitated and localized the foreland. Synrift normal faults reactivated and extensively inverted as thrust faults are prominent in the eastern 1/3 of the basin, whereas folds developed above detachments in shaley early post-rift strata dominate the western 2/3 of the basin. Songliao foreland development likely was driven by changing plate dynamics and collision along the Pacific margin after 88 Ma.

Many classification schemes of sedimentary basins have been developed but an effective classification system remains elusive, rendering communication and comparisons difficult. Here we propose a simple yet robust classification scheme based on driving mechanisms and lithosphere mechanical properties. We decompose and categorize basins into rift, sag, continental margin, foreland, and pull apart prototype basins, induced by driving mechanisms of thermal upwelling, cooling subsidence, isostasy subsidence, orogenic loading and transtension. Each prototype has its specific varieties related to different lithospheric mechanical properties, including characteristic structural style, magmatic activity, sedimentary sequences, depositional facies and hydrocarbon potential. The simplified classification scheme is instrumental in better understanding and characterizing sedimentary basins within a unifying global tectonic framework.

Understanding how depositional environments within a sedimentary system redistribute and sequester sediment is critical for interpreting basin-scale provenance trends. However, sedimentary source-to-sink models commonly examine temporal changes and do not consider how variation in sedimentation processes across a dispersal pathway may result in contrasting provenance signatures. In this paper, we demonstrate a down-paleoslope shift in detrital zircon provenance signatures correlated with shallow-marine lithofacies patterns from the Upper Cretaceous La Anita Formation and underlying continental slope lithofacies of the Alta Vista Formation (Magallanes-Austral Basin, southern Patagonia). New stratigraphic, sedimentologic, and lithofacies analysis results from the La Anita Formation suggest an upward shoaling succession, from a 1) storm-influenced shoreface, 2) fluvially dominated, wave-influenced delta, and a 3) high-energy, gravelly foreshore. Stratigraphic sections are paired with U-Pb detrital zircon sandstone samples (N = 20; n = 5,219), which provide both maximum depositional ages and provenance characteristics. While all samples contain abundant zircon derived from the Andean volcanic arc (ca. 145–75 Ma), the amount from both Jurassic distal volcanic massifs (ca. 188–162 Ma) and recycled orogenic sources exhumed during the advance of the Cretaceous fold-and-thrust belt (>200 Ma; 157–142 Ma) vary with changes in depositional environment. We argue that down-paleoslope, systematic enriching of local fold-and-thrust belt material within the La Anita Formation is reflective of progressive mixing of grains transported via shallow-marine processes, while distally enriched fluvio-deltaic transported zircons were sourced from large, regional catchments. This suggests that competition between transport processes across a shallow and marginal marine sequence of rocks affects the resulting provenance signatures recorded within a single stratigraphic succession. These data also detail the degree of sediment pathway connectivity between shallow-marine sources and deep-marine sinks. Detrital zircon results from muddy continental slope facies of the Alta Vista Formation are made up entirely locally derived material, while zircon results from deep-water, sand-rich channel facies of the Formation are indistinguishable from coeval fluvio-deltaic zircon signatures. This implies that continental shelf-to-slope connectivity in a sediment dispersal system, via submarine canyons or shelf-edge delta progradation, is necessary for detrital zircon distributions from the shallow-marine realm to propagate into the deeper marine.

The New Idria serpentinite body in the Coast Ranges of California is a diapir that resulted from the interaction of the migrating Mendocino trench-ridge-transform fault triple junction, transpression, metasomatic fluids, and previously subducted oceanic crust and mantle. Northward propagation of the San Andreas fault progressively eliminated the original subduction zone, allowing seawater to penetrate into the formerly subducting abyssal peridotite mantle, triggering serpentinization. The associated physical changes in density, volume, and strength yielded an expanding, buoyantly rising serpentinite protrusion, facilitated by transpression along the San Andreas fault. Sedimentary facies and intrusion of minor cross cutting syenite and alkali basalt dikes indicate that the serpentinization-driven diapir buoyantly rose and widely breached the surface by ca. 14 Ma, attending migration of the Mendocino Triple Junction past the latitude of New Idria.

Crustal deformation occurs both as localized slip along faults and distributed deformation off faults; however, we have few robust geologic estimates of off-fault deformation over multiple earthquake cycles. Scaled physical experiments simulate crustal strike-slip faulting and allow direct measurement of the ratio of fault slip to regional deformation, quantified as Kinematic Efficiency (KE). We offer an approach for KE prediction using a 2D Convolutional Neural Network (CNN) trained directly on images of fault maps produced by physical experiments of strike-slip loading of wet kaolin. A suite of experiments with different loading rate and basal boundary conditions, contribute over 13,000 fault maps throughout strike-slip fault evolution. Strain maps allow us to directly calculate KE and its uncertainty, utilized in the loss function and performance metric. The trained CNN achieves 91% accuracy in KE prediction of an unseen dataset. We then apply this CNN trained on wet kaolin experiments to strike-slip experiments in dry sand. The different rheology of sand and kaolin may lead to different relationships between fault geometry and off-fault deformation, which can be detected by differences in the predictive power of the CNN trained only on kaolin. We also apply the trained CNN to crustal maps of off-fault deformation over coseismic, 10ka and 1 Ma time scales. The CNN predicted off-fault deformation overlap available geologic estimates.

The correlation of the ca. 23 Ma Pinnacles and Neenach volcanic complexes provides the most robust estimate on the timing and magnitude of Neogene right-lateral displacement on the San Andreas strike-slip fault system (California, United States). Displacement of similar to 315 km has been applied rigorously along the plate margin to guide reconstruction of offset paleogeographic features. We present new detrital zircon U-Pb geochronology from the La Honda and western San Joaquin basins to document sediment provenance and reevaluate compositional constraints on a hypothesized key cross-fault tie (i.e., Castle Rock-Recruit Pass submarine fan system). Whereas the Upper Oligocene-Lower Miocene Vaqueros Formation of the La Honda basin was likely recycled from or shared a similar southern Sierra Nevada-western Mojave source with the underlying Eocene stratigraphy, we found that the Temblor Formation of the central Temblor Range (e.g., Recruit Pass submarine fan) was derived directly from Late Cretaceous northern Salinian basement. Furthermore, the Carneros Sandstone of the northern Temblor Range had a central Sierra Nevada batholith source that was likely recycled during early Miocene unroofing of the underlying stratigraphy. Conversely, strata of the southwest San Joaquin basin have provenance characteristics that match more closely with those of the La Honda basin. Our data preclude a contiguous Castle Rock-Recruit Pass submarine fan system across the San Andreas fault. These relationships are resolved by restoring the ca. 105-100 Ma basement of the northernmost Salinian block an additional similar to 45 km or greater farther south relative to the Sierra Nevada batholith during late Oligocene-early Miocene time. Inconsistency in displacement along the San Andreas fault with the coeval correlation of the Pinnacles-Neenach volcanic complex is reconciled by post-depositional Miocene-Quaternary off-fault NW-SE structural shortening via major thrusts and/ or transrotation of the Tehachapi block, in combination with extension of the northern Salinian block. This additional displacement reduces the need for pre-28 Ma slip on the San Andreas or predecessor faults to resolve Cretaceous through Eocene cross-fault relationships and reconciles an early Miocene discrepancy with Pacific-North America relative plate motion. This study highlights the fact that displacement histories of major strike-slip faults are divergent across changing structural domains, and recognition of slip disparities can constrain the magnitude of deformation.

From the latest Cretaceous (late Campanian to Maastrichtian, -75?66 Ma) to the earliest Paleogene, fluctuations in greenhouse climate, inferred primarily from marine sediments, have been linked to volcanism, the Chicxulub asteroid impact, and the Cretaceous-Paleogene (K-Pg) mass extinction. In this paper, we summarize terrestrial climate records in mid-latitude East Asia during the latest Cretaceous and across the K-Pg boundary, based on a multi-proxy approach from the geochronologically well-constrained Sifangtai and Mingshui formations (SMF), accessed by scientific drilling of the Songliao Basin in northeastern China. Evolution of sedimentary environments is characterized by five depositional units of fluvial-deltaic-lacustrine facies. Development of four types of paleosols, including Inceptisols, Aridisols, Vertisols and Alfisols, is interpreted to primarily reflect climatic changes. Correlations among sedimentary facies, paleosol features, illite chemistry index, chemical index of alteration, as well as stable and clumped isotopes of pedogenic carbonates and clay minerals of the SMF validate their reliability for paleoclimate reconstruction, and indicate significant fluctuations in terrestrial climate and sedimentary environment. During global warming intervals possibly triggered by volcanism (e.g. -69.5?68.5 Ma), the Songliao Basin experienced a warmer and wetter climate with stronger terrestrial chemical weathering and more monsoon-derived moisture sourced from the Pacific. In contrast, during global cooling intervals (e.g. -70.5?69.5 Ma and - 68.5?66.5 Ma), the SMF record a cooler and drier climate with less intensive chemical weathering and more westerlies-derived moisture. Across the K-Pg boundary, dramatic changes in land temperatures and hydroclimate correspond to the latest Maastrichtian warming episode (-66.4?66.1 Ma), the transient cooling preceding the K-Pg boundary (-66.1?66.0 Ma), and the earliest Paleogene warming interval (-66.0?65.7 Ma). Temporal correlation of weathering index changes with the Deccan Traps volcanism suggests that volcanism and subsequent intensified weathering played a major role for climatic changes across the K-Pg boundary. The integrated records of sedimentological and geochemical datasets from the Songliao Basin robustly demonstrate that the terrestrial climate of mid-latitude East Asia responded strongly to greenhouse climate changes and to the catastrophic geological events from the latest Cretaceous to the earliest Paleogene.

ABSTRACT The Mount Diablo region has been located within a hypothesized persistent corridor for clastic sediment delivery to the central California continental margin over the past ~100 m.y. In this paper, we present new detrital zircon U-Pb geochronology and integrate it with previously established geologic and sedimentologic relationships to document how Late Cretaceous through Cenozoic trends in sandstone composition varied through time in response to changing tectonic environments and paleogeography. Petrographic composition and detrital zircon age distributions of Great Valley forearc stratigraphy demonstrate a transition from axial drainage of the Klamath Mountains to a dominantly transverse Sierra Nevada plutonic source throughout Late Cretaceous–early Paleogene time. The abrupt presence of significant pre-Permian and Late Cretaceous–early Paleogene zircon age components suggests an addition of extraregional sediment derived from the Idaho batholith region and Challis volcanic field into the northern forearc basin by early–middle Eocene time as a result of continental extension and unroofing. New data from the Upper Cenozoic strata in the East Bay region show a punctuated voluminous influx (>30%) of middle Eocene–Miocene detrital zircon age populations that corresponds with westward migration and cessation of silicic ignimbrite eruptions in the Nevada caldera belt (ca. 43–40, 26–23 Ma). Delivery of extraregional sediment to central California diminished by early Miocene time as renewed erosion of the Sierra Nevada batholith and recycling of forearc strata were increasingly replaced by middle–late Miocene andesitic arc–derived sediment that was sourced from Ancestral Cascade volcanism (ca. 15–10 Ma) in the northern Sierra Nevada. Conversely, Cenozoic detrital zircon age distributions representative of the Mesozoic Sierra Nevada batholith and radiolarian chert and blueschist-facies lithics reflect sediment eroded from locally exhumed Mesozoic subduction complex and forearc basin strata. Intermingling of eastern- and western-derived provenance sources is consistent with uplift of the Coast Ranges and reversal of sediment transport associated with the late Miocene transpressive deformation along the Hayward and Calaveras faults. These provenance trends demonstrate a reorganization and expansion of the western continental drainage catchment in the California forearc during the late transition to flat-slab subduction of the Farallon plate, subsequent volcanism, and southwestward migration of the paleodrainage divide during slab roll-back, and ultimately the cessation of convergent margin tectonics and initiation of the continental transform margin in north-central California.

Earth and Space Science Open Archive This preprint has been submitted to and is under consideration at Geophysical Research Letters. ESSOAr is a venue for early communication or feedback before peer review. Data may be preliminary.Learn more about preprints preprintOpen AccessYou are viewing the latest version by default [v1]Prediction of Off-Fault Deformation from Experimental Strike-slip Fault Structures using the Convolutional Neural NetworksAuthorsLaainamChaipornkaewiDHannaElstoniDMichele L.CookeiDTapanMukerjiStephan AlanGrahamSee all authors Laainam ChaipornkaewiDCorresponding Author• Submitting AuthorStanford UniversityiDhttps://orcid.org/0000-0003-2021-3655view email addressThe email was not providedcopy email addressHanna ElstoniDUniversity of Massachusetts AmherstiDhttps://orcid.org/0000-0002-2420-5241view email addressThe email was not providedcopy email addressMichele L. CookeiDUniversity of Massachusetts AmherstiDhttps://orcid.org/0000-0002-4407-9676view email addressThe email was not providedcopy email addressTapan MukerjiStanford Universityview email addressThe email was not providedcopy email addressStephan Alan GrahamStanford Universityview email addressThe email was not providedcopy email address