No description available.

No description available.

Cenozoic deposits in intermontane basins in the upper Gila River basin have been collectively included in the Gila conglomerate of Gilbert and Ransome. Re-examination of type-section areas shows that the term is unsatisfactory because it includes a substantial proportion of deposits other than conglomerates; it suggests that deposits in separate basins are identical; its use masks sequences of alluvial deposits within individual basins and relationships of deposits between basins; and it oversimplifies a complex Cenozoic history. It is suggested that the term Gila conglomerate be abandoned. The deposits, in the many basins, which heretofore may have been included in the Gila conglomerate, can be separated into two major divisions which may in turn be subdivided into mappable rock units. In each structural trough the upper units are characterized by: (1) Truncation by the highest pediment surfaces; (2) depositional or normal-fault contact with adjacent mountain areas whose composition the deposits reflect; (3) size-gradation relationships that suggest deposition within the boundaries of the present structural troughs; and (4) lack of mineralization. Limited fossil evidence suggests that deposition occurred during Pliocene to Pleistocene (Kansan) time. The lower units crop out in areas of deep dissection or structural uplift. They may be in fault contact with the upper units, underlie them unconformably, or grade into them. The lower units are characterized by: (1) Texture and composition that suggest deposition in basins other than those reflected by the present topography; (2) thrusting or normal faulting more complex than that associated with the upper units; (3) local mineralization; and (4) shallow intrusion. Limited fossil evidence sug gests a Miocene age for some of the older of the lower units, The alluvial deposits in individual basins in this area are amenable to stratigraphic analysis by standard procedures for describing rock units Correlations within or between basins should be on the basis of proper fossil or stratigraphic evidence and should be limited to the particular units involved and not expanded to include all the alluvial deposits in the areas concerned.

No description available.

Thesis (Ph. D.)--University of Pennsylvania, 1935. / "Reprint from the Museum journal, vol. XXIV, nos. 2-3." "Publications of the University museum, June 1935": p. 172-175. Bibliography: p. 152-158.

No description available.

No description available.

No description available.

No description available.

Outcrops of the Abo Formation (Wolfcampian to early Leonardian age) in the Sacramento Mountains of south-central New Mexico record the evolution of a dry alluvial fan system as it was deposited off of the Pedernal Uplift into the Orogrande Basin. A mud-rich, upward-fining basin-fill sequence characterized by stratigraphic thickness variations of as much as 450 m (1480 ft) and contacts that range from conformable to unconformable relationships is observed in the outcrop area. Five distinctive lithologic intervals are delineated in the Sacramento Mountains, three of which are studied in detail. These three units are informally designated the lower, middle, and upper Abo intervals and are all fluvial in origin. The remaining two intervals, the Lee Ranch Tongue of the Abo Formation and the Pendejo Tongue of the Hueco Limestone, are marginal marine in origin and are restricted to the southern portion of the range. Two types of lithofacies are present in the lower, middle, and upper Abo intervals. Matrix facies represent fine-grained overbank sediments, whereas framework facies represent coarser streamflow and sheetflow deposits. Lower Abo framework facies consist of middle-fan to fan-fringe stream-channel, braided stream, and sheetflood deposits which are arranged in one or more stacked, assymetrical, upward-fining megasequences 10-50 m (33-165 ft) in thickness. Middle and upper Abo framework facies were deposited basinward of the fans and represent deposits of incised, low to moderate sinuosity ephemeral streams and associated overbank splays. Middle Abo streams exhibited an anastomosed channel pattern whereas upper Abo channels were characterized by a distributive pattern. Pedogenic and sedimentologic evidence suggests that Abo deposition was strongly influenced by a long term, semi-arid to arid climate. Lateral and vertical facies relationships indicate that the five Abo intervals were part of a northeast to southwest transverse facies tract consisting of 1) proximal alluvial fans, 2) medial anastomosed streams, and 3) distal low-gradient mud-dominated floodbasins characterized by either distributary streams or tidal flats with associated marine carbonates. The overall Abo basin-fill sequence reflects the migration of the facies tract in response to the final stages of tectonic activity and the eventual quiescence and long-term erosion, retreat (pedimentation), and onlap of the Pedernal Uplift. / text