|Premise||Member defined by van Adrichem Boogaert & Kouwe (1993). Originally used informally by Conoco as the ’Mottled Unit Member’.|
|Derivatio nominis||Named after the village of Driehuis, in the south of the Dutch province of Noord-Holland. It lies approximately on strike projection from the offshore type locality.|
|Type section||Location map||See figure (pdf)|
|Depth||2115 to 2403 m|
|Length||288 m along hole|
|Reference||261 m TVD|
|Definition||Sequence of mainly mottled and variegated grey, cream, light-grey, purple-grey, and locally orange-brown claystones and siltstones, often highly sideritic, with occasional interbeds of thin, fine-grained sandstones.|
|Upper Boundary||The member is conformably overlain by the Bloemendaal Member, or it is unconformably overlain by younger sediments. Laterally, the member grades into the interbedded sandstones, siltstones and claystones of the Santpoort and Bloemendaal Mbs. Where the Santpoort Member is not recognised, the Driehuis Member can not be assigned, although it can tentatively be correlated with the upper part of the Fourteens Claystone Member in those areas (e.g. Q01).|
|Lower Boundary||The member is conformably underlain by the interbedded sandstones, siltstones and claystones of the Santpoort Member.|
|Distribution||Restricted to those parts of the Broad Fourteens Basin where the Santpoort Member is recognised.|
|Age||Portlandian in age. Characteristic flora associations in the lower half of the member contain Microdinium opacum and Cribroperidinium spp., while younger sections contain Classopollis spp., other sporomorphs, Celyphus rallus and Botryococcus spp., indicative of decreasing marine influence. Reworking of Early Kimmeridgian palynoforms is common. In the type section, the uphole drop in Classopollis, characteristic for the top of the Portland-ian, is found in this member.|
|Depositional Setting||Sediments have been interpreted to be coastal-plain to flood-plain deposits with relatively little influence of fluvial channels. The variegated, mottled colours indicate a fluctuating water-table, causing alternating periods of oxidisation and reduction. Marine influence (especially towards the base) can be concluded from intercalations containing abundant dinoflagellates.|
|Sequence Stratigraphy||Top and bottom ages can vary considerably, mainly due to the diachronous character of the bounding sandstone members. Deposition predominantly took place during sequences LZB 1.3 and LZB 1.4, but in the type section the member also incorporates sequence LZB 1.5a (up to Early Highstand).|
|References||See References Upper Jurassic/ Lower Cretaceous|
Van Adrichem Boogaert, H.A. & Kouwe, W.F.P., 1993-1997. [Stratigraphic unit]. In: Stratigraphic Nomenclature of the Netherlands.
Retrieved [Datum] from [url].