Thickening-upward cycles in deep-marine and deep-lacustrine turbidite lobes: examples from the Clare Basin and the Ordos Basin

Abstract

Deep-marine and deep-lacustrine reservoirs have been targets for conventional and unconventional oil and gas exploration and development for decades. Thickening-upward cycles in the deep-marine Carboniferous Ross Sandstone Formation outcrops in western Ireland and the deep-lacustrine Triassic Yanchang Formation outcrops in southeast Ordos Basin have been investigated and correlated in this study. Typical thickening-upward cycles consisting of, from bottom to top: (1) laminated shales/shales with interbedded siltstone beds; (2) interbedded sandstones/siltstones and mudstones; (3) structureless massive sandstones, are well recognized in these outcrops and are interpreted as turbidite lobes. A continuously prograding lobe-element model is proposed to explain the repeated stacking of thickening-upward cycles. Thickening-upward cycles developed within deep-marine and deeplacustrine environments are highly comparable in many aspects, such as sedimentary structures, sheet-like geometries and amalgamation features. A frequent and strong degree of amalgamation is developed within the massive sandstone at the top of each thickening-upward cycle, suggesting a layer-by-layer depositional manner. Field observations and comparison with deep-marine counterparts support the occurrence of turbidity flows in the Yanchang Formation, Ordos Basin.

Hybrid event bed character and distribution in the context of ancient deep‐lacustrine fan models

“…All rights reserved character widely explored (e.g. Davis et al, 2009;Hodgson et al, 2009;Kane et al, 2017;Spychala et al, 2017a;2017b;Bell et al, 2018;Pierce et al, 2018;Baas et al, 2021), their occurrence and variability in deep-lacustrine fan settings is less understood, with there being few published examples (Hovikoski, et al, 2016;Tan et al, 2017;Dodd et al, 2019;Yang et al, 2019;Zhang & Dong, 2020;Shan et al, 2020).…”

“…These flow types have been modelled experimentally (Baas et al ., 2009, 2011; Sumner et al ., 2009, 2012). Despite being well‐documented in marine environments (Haughton et al ., 2009; Pierce et al ., 2018), and HEB distribution and character widely explored (Hodgson et al ., 2006; Davis et al ., 2009; Kane et al ., 2017; Spychala et al ., 2017a,b; Bell et al ., 2018; Pierce et al ., 2018; Baas et al ., 2021), their occurrence and variability in deep‐lacustrine fan settings is less understood, with there being few published examples (Hovikoski, et al ., 2016; Tan et al ., 2017; Dodd et al ., 2019; Yang et al ., 2019; Shan et al ., 2020; Zhang & Dong, 2020).…”

Eocene to middle Miocene contourite deposits in Cyprus: A record of Indian Gateway evolution

“…Shorter-term thickening-upward sequences within contourite packages have been described previously in other deepwater setings, and they may reflect margin progradation caused by eccentricity cycles, as proposed for other continental slopes dominated by contourite deposition. (Boulila et al, 2012;Boulila et al, 2018;Boulila et al, 2020;Cloetingh et al, 1990;Cochran, 1990;Cogné and Humler, 2004;Coltice et al, 2013;Derbyshire, 1996;Hernández-Molina et al, 2016;Ikeda and Tada, 2013;Jones et al, 2012;Laskar et al, 2011;Liu, 2019;Llave et al, 2001;Lourens and Hilgen, 1997;Lovell, 2010;Maclennan and Lovell, 2002;Mather et al, 2020;Mestdagh, 2020;Mestdagh et al, 2019;Mjelde et al, 2010;Montadert et al, 2010;Praeg et al, 2005;Rampino et al, 2021;Rodríguez-Tovar, 2014;Rudge et al, 2008;Van Rooij et al, 2003;Van Rooij et al, 2010;White and McKenzie, 1989;Whyte and Lovell, 1997;Zhang and Dong, 2020) time, basin deposition consisted of distal and relatively deepwater (lower slope) deposition by water masses flowing northwest (Fig. 22A).…”

Facies Analysis and Sedimentary Architecture of Hybrid Event Beds in Submarine Lobes: Insights from the Crocker Fan, NW Borneo, Malaysia

“…In addition to this, the fring area of frontal lobes is prone to hybrid events that primarily contain the mud-rich hybrid bed (H3 and H5 facies) because of depositional transition from massive clean sand int muddy sand throughout the deep-marine gravity flow [33]. Hybrid event beds are frequently reported in the distal lobe system having abrupt pinch out and wedging in beds due to deceleration of flow [2,16,18,21,30,81]. Likewise, linked debrites are usually associated with the proximal and medial settings with higher energy flow, whereas the distal lobes have less vertical thickness of hybrid beds [18,46] as the energy conditions in massive and thick sand packages are already transformed in the proximal and medial lobe settings.…”