\u3ci\u3eSoundboard Scholar\u3c/i\u3e no. 5: Editor\u27s Letter

An introduction to the contents of this issue

\u3ci\u3eSoundboard Scholar\u3c/i\u3e no. 3: Editor\u27s Letter

An introduction to the contents of this issue

\u3ci\u3eSoundboard Scholar\u3c/i\u3e no. 4: Editor\u27s Letter

An introduction to the contents of this issue

\u3ci\u3eSoundboard Scholar\u3c/i\u3e no. 1: Editor\u27s Letter

An introduction to the aims and scope of this new scholarly journal of the guitar, and an introduction to the individual articles

\u3ci\u3eSoundboard Scholar\u3c/i\u3e no. 2: Editor\u27s Letter

An introduction to the contents of this issue

Editorial: Guitar Research Resources—An Update

In early May, 2015, there was a biennial gathering of guitar history enthusiasts and scholars at the town of Hemmenhofen, Germany, on Lake Constance. One of the sessions was a round table with the title, Old and New Sources and Horizons for Historical Research on the Guitar. It was designed to stimulate audience participation and certainly succeeded. Brief papers were offered by three scholars in attendance. Here, Heck identifies eight points of progress, each of which can be considered good news for those who work in the field of guitar history

Depositional environments and diagenesis of the Mississippian Bottineau interval (Lodgepole) in North Dakota

Bottineau interval rocks from the North Dakota part of the Williston Basin comprise a single marine transgression/regression cycle, Early Mississippian (lower Scallion subinterval) marine transgression from the restricted depositional environment of the Bakken Formation resulted in normal marine circulation, Six major facies were developed: (1) the central basin, (2) basin flank, (3) open shelf, (4) crinoidal mudstone, (5) gray shale, and (6) restricted shelf. Marine transgression continued until upper Scallion subinter val time, by which time the open shelf facies had already prograded over the gray shale and crinoidal mudstone facies. Marine regression had begun by middle Bottineau interval (Virden subinterval) deposition. Three younger shallow water facies were developed along the margin of the basin: (1) the pelletal grain stone, (2) oolite grainstone, and (3) lagoonal. These facies pro graded basinward over deeper water facies as marine regression con tinued until, by Flossie Lake subinterval time, these shallow water facies were being deposited in the central basin area. Bottineau interval sedimentation terminated with continued marine regression and a transition to deposition of shallower water Tilston interval sediments. Two diagenetic provinces, basin and shelf, with different dia genetic histories, were identified in Bottineau interval rocks. Dia genetic processes were post- or pre-lithification events. Prelithification processes included biologic acthity, compaction, soft sediment deformation, pyrite replacement, cementation, and neomorphism. Biologic activity occurred early, both during and after deposition, Pyrite replacement, soft sediment deformation, precipitation of fringing cement, and microstylolitization occurred shortly after deposition. Later precipitation of equant and overgrowth cements prevented further microstylolitization in cement-lithified fabrics. All pre-lithification processes ceasec once cementation and neomorphism had completely lithified the sediments. Post-lithification processes included stylolitization, solution, fracturing, silicification, hematite replacement, dolomitization, and anhydritization. Stylolitization and fracturing began after complete lithification, as did silicification which produced chert nodules in the restricted shelf facies. This was followed by hematite replacement of matrix and allochems. Solution voids formed prior to, or during dolomitization as meteoric waters dissolved skeletal allochems. Anhydritization was the last event observed to have altered Bottineau interval rocks. Areas of potential petroleum production exist from the L2 interval in northwestern North Dakota, from structural traps resulting from salt solution of the Prairie Formation in north-central North Dakota, and from structural and stratigraphic traps along the erosional unconformity in eastern North Dakota

Frequency response of the superconducting gravimeter SG056

The two sensors of the SG 056 double-sphere superconducting gravimeter at BFO (Black Forest Observatory, Germany) show differences in their response to long-period seismic signals. Their frequency response deviates from the nominal GGP1-filter (8th-order Bessel low-pass). We experimentally derive parameterized models for the sensor’s full frequency response by application of square-wave and down-sweep drive signals to the feedback circuit and subsequent inversion. The latter is carried out with the program calex in the time domain which iteratively minimizes the least-squares misfit between the output signal predicted with the filter model and the actual output of the sensor. We seek for values of eigenperiod and damping of the four 2nd-order subsystems of 8th-order low-pass filters. The resulting filters deviate considerably from the nominal response of the GGP1-filter also in that they are not Bessel filters. Remaining residuals indicate that the models are not able to capture the exact response. Nevertheless, they substantially reduce amplitudes of waveform-residuals in long-period earthquake recordings by a factor of four. The filter response curves approach their DC-limit (frequency f = 0Hz) within the frequency band of the drive signals. Thus we estimate the asymptotic signal delay ΔtDC to be considered in tidal analysis to be ΔtDCG1 = 10.44s for the lower sensor G1 (heavier sphere) and ΔtDCG2 = 9.86s for the upper sensor G2 (standard sphere). The accuracy of these values appears to be not better than 0.07s. For signals recorded with voltmeters on the UIPC data-acquisition and distributed through the IGETS data center (formerly GGP) ΔtDCG1 = 9.84s and ΔtDCG2 = 9.26s