Mass‐transport Deposits of the Upper Cretaceous Qingshankou Formation, Songliao Terrestrial Basin, Northeast China: Depositional Characteristics, Recognition Criteria and External Geometry

Abstract

Extensive mass transport deposits (MTDs), which form a significant component of the stratigraphic record in ancient and modern deep water systems, mostly distributed in the continental margin of ocean basins worldwide. To date, no large‐scale MTDs have been found in Chinese terrestrial basins. Based on integrated analysis of the seismic, drilling, core and logging data, this article report MTDs have been found in Songliao terrestrial basin (SLTB), Northeast China. During the depositional period of the Upper Cretaceous Qingshankou Formation, slope break of lacustrine basins was an ideal discharge place for gravity depositions. Regional sedimentary study of MTDs reveals that Cretaceous‐age MTDs in SLTB were deposited in slope‐break environments by slide, slump and debris flow, and MTDs were mixed with little turbidite simultaneously. Besides the massive aspect, key features of MTDs are the common presence of deformational structures or soft‐sedimentary deformation, floating shale clasts, boudins, microfaults, distortion beddings, rotated sand debris. Detailed mapping of two three‐dimensional (3‐D) seismic surveys acquired in Yingtai (YT) and Haituozi (HTZ) areas reveals that MTDs are characterized by chaotic, mounded, and transparent seismic reflection. Growth fault, slope gully and geomorphology of the slope break greatly influenced the sedimentary process and external geometry of MTDs, and as a consequence, MTDs in SLTB exhibit classic fan‐like geometry and some special (non‐fan‐like) external geometry. Furthermore, fan‐like MTDs can be divided into three subcategories, including isolated fan, mother‐son fan and stacked fan. Non‐fan‐like MTDs can be divided into two subcategories, strip‐like MTDs and faulted‐pit MTDs. A new sedimentary model has been built for MTDs in SLTB. MTDs have become a new exploration and development target in the SLTB.

Giant sublacustrine landslide in the Cretaceous Songliao Basin, NE China

“…However, as important oil and gas‐productive areas of the world, similar deposits and their economic significance in lacustrine settings are poorly studied. With the development of the hydrocarbon exploration industry, gravity flow deposits have become a major target for oil and gas reservoirs growth in worldwide continental basins (Pan, Liu, et al, ; Pan et al, ). Meanwhile, the genesis of gravity flows has gained considerable attention from sedimentary petrologists.…”

“…Meanwhile, the genesis of gravity flows has gained considerable attention from sedimentary petrologists. During the past 20 years, vast turbidities have been found in worldwide continental basins (Pan, Liu, et al, ; Pan et al, ; Zavala & Arcuri, ). However, the evidence presented here clearly indicates that a sublacustrine landslide occurred in the deltaic slope of the SLB.…”

Pore Structure Characteristics and Affecting Factors of Shale in the First Member of the Qingshankou Formation in the Gulong Sag, Songliao Basin

“…The overall stratum burial depth varies significantly; however, the stratum thickness varies slightly, and the structural fault zones are less developed (Figure e). Because of the occurrence of anoxic events near the Cenomanian–Turonian boundary of the K2qn 1 formation, dark shale rich in organic matter (OM) was deposited . In addition, the lithology of the K2qn 1 formation also includes fine grained sediments, such as mud dolomite, shell limestone, and argillaceous siltstone (Figure d).…”

“…Because of the occurrence of anoxic events near the Cenomanian–Turonian boundary of the K2qn 1 formation, dark shale rich in organic matter (OM) was deposited. 26 In addition, the lithology of the K2qn 1 formation also includes fine grained sediments, such as mud dolomite, shell limestone, and argillaceous siltstone 26 ( Figure 1 d). The shale in the K2qn 1 formation of the Gulong Sag is currently in the production breakthrough stage.…”

Multiple-stacked Hybrid Plays of lacustrine source rock intervals: Case studies from lacustrine basins in China

“…7a). Within the Qingshankou source rock interval, the organic-rich shale in semi-deep to deep lake settings are often associated with thin siliciclastic silty shale, turbidite sandstones, siltstone, and sandy mass transport deposits (MTDs), even occasionally associated with ostracod grainstone and marls (Pan et al 2014;Fig. 7b-d).…”