Structural, Sedimentologic, and Sea-Level Controls on Sand Distribution in a Steep-Clinoform Asymmetric Wave-Influenced Delta: Miocene Billund Sand, Eastern Danish North Sea and Jylland

Abstract

The lower Miocene Billund sand of Jylland, Denmark, provides an excellent opportunity to study the distribution of sands and the types of clinoform generated by a wave-dominated delta prograding into a deep shelf environment. In particular seismic sections, the sand-rich parts correlate with parallel clinoformal seismic facies, in which the clinoforms dip 7u to 10u. The stacking pattern of this seismic facies also indicates whether the progradation occurred during rising or falling sea level by displaying an ascending or descending shoreline trajectory, respectively. The Billund delta was deposited in the eastern North Sea Basin during the early Miocene and is on the available data recognized as a NW to SE trending feature. It forms a wave-dominated delta with thick sand bodies deposited in relatively deep waters (. 100 m) at the river mouth and in the updrift area of newly formed delta lobes. Sands and muds associated with a spit complex or a lagoonal complex dominated the down-drift area. In the distal delta-front area, alternating sands and muds were laid down, the sands associated mainly with storm events. Progradation of the studied part of the delta occurred during high sea level and a subsequent fall in sea level that was caused by a eustatic fall during the mid Aquitanian (early Miocene). Although sand intervals 10 to 20 m thick are common throughout the delta complex, the thickest (up to 100 m) and cleanest sand is found in units deposited in narrow bands within structural lows and during periods of forced regression. The Billund delta may be an excellent analogue for hydrocarbonbearing, wave-dominated deltas, and seems to exhibit similarities to Jurassic deposits in the North Sea area.

Distribution of Clay Minerals In the Northern North Sea Basin During the Paleogene and Neogene: A Result of Source-Area Geology and Sorting Processes

“…During deposition of the Vejle Fjord Fm., sand-rich delta lobes (Billund Fm.) were strongly controlled by the existing topography Hansen and Rasmussen 2008) and thus dominated by isolated deltas. During the deposition of the Klintinghoved Fm.…”

“…The irregular distribution of kaolinite that particularly characterizes the Vejle Fjord Fm. reflects depositional control of delta lobes that followed an antecedent basin topography formed in association with early Miocene inversion tectonism (Hansen and Rasmussen 2008;Rasmussen 2009). This inversion tectonism ceased during the early Miocene, so that a more regular pattern characterizes the Klintinghoved and Arnum Fms.…”

Clinoforms and clinoform systems: Review and dynamic classification scheme for shorelines, subaqueous deltas, shelf edges and continental margins

“…However, they are often well-imaged by GPR data (Jol et al, 1996(Jol et al, , 2002Smith and Jol, 1997;Hampson et al, 2008) (Fig. 11a) or high-resolution shallow seismic (Tesson et al, 2000;Hansen and Rasmussen, 2008;Rasmussen, 2009). They are also demonstrated in outcrops (Gani and Bhattacharya, 2005;Hampson et al, 2008; (Fig.…”

Oligocene climate changes controlling forced regression in the eastern North Sea

“…Previously described high-angle clinoform systems have been reported from onshore Denmark (Early Miocene: Hansen and Rasmussen, 2008) and from the Danish Central Graben (Late Miocene: Møller et al, 2009). These clinoform complexes were interpreted to represent wave-dominated deltas and were utilized as such in the paleogeographic reconstructions proposed by Rasmussen et al (2008).…”

“…This is in contrast with observations from our study area, but the clinoforms studied here extend outside the study area and therefore we cannot exclude a depositional scenario similar to the one from the Late Miocene. The interpretation of the Early Miocene clinoforms is based on few 2D seismic lines, but is constrained by numerous wells and outcrops, making the interpretation undisputable (Hansen and Rasmussen, 2008).…”