Quick Search:    advanced search

GSW Home   GeoRef Home   My GSW Alerts   Contact GSW   About GSW   Journals List   Help

This Article Abstract Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Noda, A. Articles by Toshimitsu, S. Search for Related Content GeoRef GeoRef Citation

Backward stacking of submarine channel–fan successions controlled by strike-slip faulting: The Izumi Group (Cretaceous), southwest Japan

¹GEOLOGICAL SURVEY OF JAPAN, NATIONAL INSTITUTE OF ADVANCED INDUSTRIAL SCIENCE AND TECHNOLOGY, CENTRAL 7, 1-1-1, HIGASHI, TSUKUBA, IBARAKI 305-8567, JAPAN

View larger version (33K): [in this window] [in a new window]   Figure 1. Location of the study area and distribution of the Cretaceous Izumi Group. White lines in the Izumi Group indicate the strike of bedding. Thick, black line represents the Median Tectonic Line (MTL).

View larger version (22K): [in this window] [in a new window]   Figure 2. Depositional ages and distribution of the axial part of the Izumi Group, from Shikoku to Awaji Island compiled from Suyari (1973), Bando and Hashimoto (1984), and Morozumi (1986) for macrofossils; Yamasaki (1987) and Hollis and Kimura (2001) for radiolarian zones; and Kodama (1990) and Kodama (2003) for magnetic polarity. Absolute ages are from Ogg et al. (2004). The abbreviations DK, AT, and PA for radiolarian zones represent the Dictyomitra koslovae, Amphipyndax tylotus, and Pseudotheocampe abschnitta assemblage zones, respectively (Yamasaki, 1987).

View larger version (44K): [in this window] [in a new window]   Figure 3. (A) Geological map for the Niihama district. Thick lines (A–D) indicate the locations of columnar sections in Figure 5. (B) Cross section along the line X–Y in A. (C) Distribution of lower and upper submarine channel–fan units.

View larger version (22K): [in this window] [in a new window]   Figure 4. Generalized lithologic columns for the study area. Lithological patterns are the same as Figure 3.

View larger version (25K): [in this window] [in a new window]   Figure 5. Representative columnar sections of the various lithofacies associations. The locations of the sections are shown in Figure 3. Abbreviations for lithology are as follows: Zs—thin-bedded graded sandstone and mudstone couplets; Zm—structureless mudstone; fS—fine-grained sandstone; mS—medium-grained sandstone; cS—coarse-grained sandstone; vcS—very coarse–grained sandstone; gGc and gGm—clast-supported and matrix-supported granule-sized conglomerates, respectively; pGc and pGm—clast-supported and matrix-supported pebble-sized conglomerates, respectively; cGc and cGm—clast-supported and matrix-supported cobble-sized conglomerates, respectively; bGc and bGm—clast-supported and matrix-supported boulder-sized conglomerates, respectively; FT—felsic tuff.

View larger version (99K): [in this window] [in a new window]   Figure 6. (A) Fining-upward, clast-supported conglomerate with boulder (up to 35 cm) clasts (facies Gc1). (B) Closely packed, nongraded, and clast-supported conglomerate (facies Gc2). A left-to-right paleocurrent is inferred from clast imbrication. (C) Matrix-supported conglomerate (facies Gm). Subangular to well-rounded clasts occur in a poorly sorted muddy coarse-sand matrix. (D) Stacks of thick- to very thick–bedded sandstone beds of facies Sm and Sg with minor intercalated thin mudstone (facies Zs). Almost all sandstone beds have a tabular geometry with sharp upper surfaces and nonerosional bases, thereby showing good lateral continuity. (E) Normal grading from pebble-sized conglomerate to coarse-grained sandstone (facies Sg). (F) Parallel- or weakly wavy-laminated interval at the top of thick structureless sandstone (facies Sm). (G) Alternating beds of thin-bedded sandstone and thin- to medium-bedded mudstone. (H) Close-up view of a wavy-laminated sandstone bed (facies Sw) intercalated with thin-bedded mudstone. The sandstone bed has an erosional base and sharp upper contact, without grading.

View larger version (25K): [in this window] [in a new window]   Figure 7. (A) Areal distribution of paleocurrent directions. Stereographs show paleocurrent data based on flute casts (B) and groove casts and clast imbrications (C).

View larger version (50K): [in this window] [in a new window]   Figure 8. Paleoslope directions inferred from slump folds. (A) Photograph of slump deposits of tightly folded thin-bedded mudstone and sandstone couplets (facies SL1); and (B) accompanying line drawing. The slump folds indicate a paleoslope dip direction from left (NE-NNE) to right (SW-SSW). (C) Rose diagram of interpreted paleoslope directions in the marginal facies, based on fold hinge data and using the mean axis method of Jones (1939).

View larger version (37K): [in this window] [in a new window]   Figure 9. (A) Listric strike-slip fault with a releasing bend, as used in the simulation. (B) Fault-bend basin resulting from 80 km of displacement along the left-lateral strike-slip fault. (C) Plan view of the basin (contour interval, 1 km). (D) Cross section of the fault (solid line) and basin topography (dashed line) along the axis of the basin, as indicated by the dashed line in C.

View larger version (38K): [in this window] [in a new window]   Figure 10. Results of five simulation cases (A–E). A1–E1: Plots showing the values used in the simulations: fault-slip distance (blue) and sediment supply (red) with time. Solid blue circles and open red squares represent fault displacement and sediment supply in each time step (right-hand vertical axis), respectively. Thick lines are cumulative values (left-hand vertical axis). The model parameters for the simulations are given in Table 2. A2–E2: Resulting lithology of basin fill. Solid lines represent the deduced present-day erosion surfaces after additional uplift and tilting. A3–E3: Deduced lithological columns along the solid lines in A2–E2.

View larger version (40K): [in this window] [in a new window]   Figure 11. (A) Depositional environments of the various lithofacies associations. (B–C) Schematic models for strike-slip basins of backward shifts of submarine channel–fan successions with progressive retreat/subsidence of the basement.

View larger version (22K): [in this window] [in a new window]   Figure 12. Schematic models for development of cyclic stratigraphy in strike-slip basins. (A) In the active phase of the strike-slip fault, rapid retreat and subsidence of the basement make the accommodation space large and relative sea-level rise. Sediment input is small in this phase due to a certain response time of sediment supply to tectonic uplift, resulting in fining- and thinning-upward successions. (B) Increase of sediment supply in association with enhancement of denudation in the uplifted source region causes progradation/aggradation of delta/submarine fan and fall of the relative sea level, and, thus, formation of coarsening- and thickening-upward successions. (C) Fining- and thinning-upward successions would be developed by gradual decrease of sediment input due to extensive erosion and retreat/subsidence of the basement, leading to relative sea-level rise.