Abstract Sand-rich turbidite systems in structurally complex, fault-bounded deep-water basins often form prolific hydrocarbon reservoirs. Outcrop studies of ancient examples of these turbidite systems provide information on architecture, depositional controls, and sandstone distribution. Outcrops of the Miocene upper Modelo Formation in eastern Ventura basin, California, are interpreted as a longitudinal transect through a fault-controlled deep-water depositional system, from proximal structural terraces, through a submarine canyon, to the basin floor and toward the basin margin. This study area is divided into three regions based on geographic location, geologic features, and stratigraphic character and architectures. Region 1, interpreted as the feeder system, contains syndepositionally active normal faults (e.g., Devil Canyon fault) near the proximal basin margin; these faults are associated with abrupt changes in depositional environments, lithofacies associations, paleobathymetry, and stratigraphic thickness. An interpreted submarine canyon, with a low net-sandstone content infill, was an area of bypass. Isopach maps reveal that gross thickness is greatest near the canyon mouth. In Region 2, interpreted as the proximal basin floor, a fairway located immediately basinward of the canyon has the highest sandstone content in the basin. In Region 3, interpreted as the medial–distal basin floor, gradual changes in proportions of lithofacies associations are the result of subtle variations in the gradient of the basin floor near the distal basin margin, as interpreted from an isopach map of the upper Modelo Formation. In this area, channel complexes comprising structureless, amalgamated sandstone overlie thin- to medium-bedded, poorly sorted, clay-rich sandstones deposited at lobe fringes. This upward architectural pattern is interpreted as a product of an outwardly expanding depocenter through time.

Abstract The Pliocene Pico and Repetto Formation turbidites of the Ventura Basin were the subject of early research on deep-water sedimentation. We focus on the subsurface Repetto Formation, primarily using cores and well logs to characterize the sandstone reservoirs and describe sand-body geometry and stratigraphic stacking. The generally poorly sorted, coarse-grained sandstone facies deposited in this elongate basin dominated by longitudinal flows have been recognized as differing from those in traditional submarine–fan–lobe facies models. They have been variously described as ribbon or shoestring sands, compensationally stacked elongate-lobe elements, and components of a braided-lobe complex. Our study utilizes recently acquired subsurface data from cores and well logs and new analytical techniques to improve our understanding of facies distributions and rock properties. Our subsurface data, however, come from only a small area of the basin and therefore afford only a limited perspective on basin-wide depositional systems. An important tool for our work is a well-log–based petrofacies model that ties directly to lithofacies. This technique enables us to delineate in significant detail lithofacies stacking patterns and lateral facies variations in wells without core. The petrofacies enable us to improve the geologic context of well-log correlation. Linked with core observations, petrofacies determination helps to define the geometry of architectural elements on the vertical scale of 50 to 100 ft (15–30 m) and laterally on the scale of typical well spacing (hundreds of feet/meters). Facies stacking and lateral relations also enable us to identify important stratigraphic surfaces. In the coarsest-grained elements, we identify two lithofacies stacking patterns that likely represent different depositional settings. Both have pebble-to-gravel–sized clasts in a sandy matrix and angular mudstone clasts at their bases. One element exhibits a fining-upward stacking pattern often characteristic of channel-fill sequences and potentially represents a distributary channel system that eventually migrates or is abandoned. The second coarse-grained element has a blocky stacking pattern consisting predominantly of amalgamated sandstone beds and remains coarse-grained nearly to the top of the unit. This depositional geometry could be consistent with a braided-lobe complex, characterized by multiple broad and low-relief channels with intervening bar forms. Both coarse-grained elements likely represent axial positions in their respective depositional settings and are relatively easy to map between wells because of the abrupt facies change at the base of the units and their relative thickness (tens of feet/meters). Thinner-bedded, finer-grained sandstone bedsets show more variability in stacking pattern and are more difficult to map over larger distances. The correlation geometry of these stratal elements is generally planar and subparallel, but individual sandstone beds are less continuous. The sandstone beds are often interbedded with mudstone and sometimes slurry deposits. We interpret these units to represent off-axis or distal deposition. Petrofacies are key for predicting reservoir properties, since porosity and permeability are closely correlated to lithofacies. For example, the petrofacies technique enables us to differentiate the coarsest-grained bedsets, deposits of high-density turbidity currents (generally poorly sorted sandstone with lower matrix porosity and permeability), from thin-bedded sandstone (generally finer-grained and better sorted, with higher matrix porosity and permeability).

Abstract References to coal can be found in many ancient Chinese books. In Hou Han Shu , for instance, the county of Chiencheng is noted for a village by the name of Ko, where “there are two ching (a unit of land measure, roughly equal to 15,300 acres - author) of coal that can be burnt in the stove for cooking” [ 58 , ch. “chih” 22, p.15b]. Chiencheng county is in the present province of Kiangsi, within the Fengcheng coal basin, according to one source, or in the present province of Anhwei, within the Huaipei coal basin, according to another source. By the time of the Sung Dynasty (960–1279 A.D.) coal mining developed into an important industry, and there were special government officials who collected coal taxes. Marco Polo (1254–1324), the Venetian traveller who visited China, or rather “Catai,” as the country was called in his time, told the amanuensis who wrote down his memoirs, that “through all the province of Catai there is found a kind of large black stones which are dug from the mountains as veins, which burn and make flames like logs and consume away like charcoal” and that “these stones are so good that nothing else is burnt through all the province of Catai as far as possible” [ 59 , p.249]. The Ming writer Sung Ying-hsing in his book T’ien Kung K’ai Wu details the use of coal in blacksmith’s work, the types of coal in the North and South, methods of exhausting gases from coal pits, ways of