Мурманская МИЛЯ. 2018 г. №4.

EXPLORATIONS 26 Data acquisition technique Seismic survey was performed using the following equipment: Sercel SEAL 428 re­ cording system, Sercel SEAL Sentinel Solid 24bit - digital streamer with the spacing of 12.5 m, 648 channels with the active section length of 8,100 m, the record time was 15 sec., the interval was 2 ms, Bolt 1900 LLX airguns, shotpoint interval was 37.5 m, oper­ ating pressure was 2,000 psi. Shipboard gravity measurements were performed along with key observations in the port of Kirkenes (Norway). The measurement of anomalous gravity field was performed us­ ing CHEKAN-AM gravity meter produced by FSUE CSRI Elektropribor in Saint Petersburg. The measuring range was 10 Gal the least, the error of gravity anomaly determination - ±0.6 mGal the least, sensitiveness - 0.01 mGal. The gravity output data recording was performed in a digital form with interval of 1 sec real-time using SeaGrav software module. Differential magnetometer survey was per­ formed using SeaSpy gradiometer. Measuring transmitters (sensors) were towed at a dis­ tance of 260 m astern - the first sensor, 360 m - the second sensor, differential system ba­ sis was 100 m; sensors depression was - 1 m. Measuring results recording was conducted in digital form with the interval corresponding to the measuring cycle of 10 sec. The RMS error of measurements with ‘zero’ base was ±0.168 ч ±0.066 nT. Navigation and hydrographic support meets the UKOOA world standards. The po­ sitioning of geophysical exploration points was performed simultaneously using GPS and GLONASS satellite navigation systems in WGS-84 coordinates system. Continuous depth measuring was provided by Simrad EA600 echo sounder produced by Kongs- berg. Depth digital recording was performed using Orca navigation system. Seismic survey data processing was per­ formed using PROMAX-5000.8.5.0 software installed at DEPO Storm 3350P1 servers on the Linux OS (CentOS v.6.5).Primever. 1.7 was used as well. Gravity and magnetometer data process­ ing and interpretation was performed using GRAV and Mag001 ver.3, ArcView GIS 3.2 and Surfer 10 software systems. Seismic survey data interpretation was per­ formed in 2016 using KINGDOM-Software 8.5. In time sections reflectors associated with dep- ositional breaks can be traced: reflector A - the surface of acoustic basement, reflector PU - Permian unconformity, reflector JU - Jurassic unconformity, reflector LCU - low Cretaceous unconformity, reflector ESS11 - Apt-Albian un­ conformity, reflector ESS1 - post-Campanian unconformity, reflector ESS2 - lower Oligocene unconformity, reflector ESS3 - regional pre-Mio- ceneunconformity, reflector ESS5 - Messinian unconformity [1, 6]. The stratification of unconformities’ sur­ faces was performed on the basis of recon­ struction of the region development history taking into account eustatic movements, dep- ositional breaks determined in erosions and drilling data in the coastal area on the islands of the New Siberian Archipelago as well as in the ACEX-302 wells sections drilled in the near-pole part of the Lomonosov ridge. The drilling data of deep-hole prospect wells in the American sector of the Chukchi Sea [2, 6-8] were also used. Results There were determined the seismic strati- graphic sequences including the lower Car­ boniferous to Quaternary deposits. Besides this the lower Carboniferous to Jurassic de­ posits are presented in the Podvodnikov ba­ sin only. They wedge out on the Lomonosov flexural fault zone and the sedimentary filling of the Vilkitsky trough starts from the lower Cretaceous deposits (Fig. 2). The surface of acoustic basement go down from the De Long high along the blocks system to the north-east to the Podvodnikov basin and to the south-east - to the Vilkitsky trough. The thickness of the sedimentary cover over the most part of the area exceeds 2 km. In the area of the Podvodnikov basin and the Vilkitsky trough it reaches 11.5 km. The Vilkitsky trough was the dominant area of deflection and sedimentation. In the mid- upper-Miocene the sedimentation depocen- tre shifted to the deep water area. The modern structure of the East Sibe­ rian continental margin is determined by the Lomonosov-Mendeleev flexural fault zone which separates the region of continental rifting, unified before, into the shelf and deep water parts. The De Long high, graben-horst East Siberian rift system, Vilkitsky trough and Demidov saddle (first identified) refer to the shelf part. The Podvodnokov basin refers to the deep water part. The De Long high is a large block of an ancient platform with crystalline basement of the Archaean to Proterozoic consolidation [5]. In the arch part of the De Long high ancient MURMANSK MILE • 4-2018