Citation:

epic.28244.d001

Name: Chronostratigraphy of sediment core CRP-2/2A (Table 1)
Published: 2000
License: https://creativecommons.org/licenses/by/3.0/

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Abstract:

The 624.15 m glaciomarine sedimentary succession recovered in the CRP-2/2A drillcore comprises lower Oligocene (<c. 31 Ma) to lower Miocene (18.5 Ma) strata that are overlain by a thin succession of Pliocene and Pleistocene strata. The age model for the CRP-2/2A drillhole, as presented in this paper, is based on combined microfossil biostratigraphy. 40Ar/39Ar age on volcanic material, 87Sr/86Sr analyses on mollusc shells, and correlation of a magnetic polarity zonation to the magnetic polarity time scale (MPTS). Between 25.92 and 109.05 metres below sea floor (mbsf), several alternative correlations to the MPTS are possible, all of which suggest that sediment accumulation rates averaged ~180 m/m.y. between unconformities, although actual sedimentation rates may have been higher. Between 109.05 and 306.65 mbsf, the age model is straightforward and average sedimentation rates were much higher (>1000 m/m.y.). Between 306.65 mbsf and the bottom of the drillcore (624.15 mbsf), fewer datums are available to constrain the age model and unique correlation with the MPTS is not possible, although high average sediment accumulation rates are likely. A significant unconformity is identified at 306.65 mbsf, which may represent as much as 5 m.y. of missing time. Additional unconformities at 25.92 and 130.27 mbsf account for c. 16 and 2.5 m.y. of missing time, respectively. The Oligocene-lower Miocene interval documented in the CRP-2/2A drillcore spans about 13 million years, however, it is possible that more time is missing in sequence-bounding unconformities than is represented in the stratigraphic record recovered in the CRP-2/2A drillcore.

Project(s):

Cape Roberts Project (CRP)

Coverage:

Latitude: -77.005980 * Longitude: 163.719450

Date/Time Start: 1998-10-16T07:30:00 * Date/Time End: 1998-11-25T14:20:00

Minimum DEPTH, sediment/rock: 36.020 m * Maximum DEPTH, sediment/rock: 624.150 m

Event(s):

CRP-2A (14.2 km at 096° true from Cape Roberts) * Latitude: -77.005980 * Longitude: 163.719450 * Date/Time Start: 1998-10-16T07:30:00 * Date/Time End: 1998-11-25T14:20:00 * Elevation: -177.9 m * Recovery: 624 m * Location: off Cape Roberts, Ross Sea, Antarctica * Campaign: * Basis: Sampling/drilling from ice * Method/Device: Core wireline system (CWS) * Comment: 921 m at 284° from CRP-1. Sea-ice thickness: 2.0 m (1 Oct) to 2.2 m (23 Nov). Sea riser embedded to 13.03 mbsf. Lateral ice movement: 9.87 m to east from 17 Oct to 23 Nov. HQ core to 199.31 mbsf. NQ core to 624.15 mbsf. 13.03 to 45.97 mbsf, 11.29 m (34%) partially following CRP-2. 45.07 to 624.15 mbsf, 548.67 m (95%) new hole. Deepest core-lithology: hard sandy siltstone. Deepest core-age: earliest Oligocene (ca. 33 Ma on diatoms, nannofossils and dinoflagellates)

Parameter(s):

#	Name	Short Name	Unit	Principal Investigator	Comment
1	DEPTH, sediment/rock	Depth sed	m		Geocode
2	Depth, top/min	Depth top	m	CRP Science Team
3	Depth, bottom/max	Depth bot	m	CRP Science Team
4	Sample code/label	Sample label		CRP Science Team
5	Age, dated material	Dated material		CRP Science Team
6	Age, dated	Age dated	ka	CRP Science Team
7	Age, dated, error to younger	Age e -	ka -	CRP Science Team
8	Age, dated, error to older	Age e +	ka +	CRP Science Team
9	Age, comment	Comm		CRP Science Team

License:

Creative Commons Attribution 3.0 Unported (CC-BY-3.0)

Size:

199 data points

Data

Download dataset as tab-delimited text — use the following character encoding:

1 Depth sed [m]	2 Depth top [m]	3 Depth bot [m]	4 Sample label	5 Dated material	6 Age dated [ka]	7 Age e - [ka -]	8 Age e + [ka +]	9 Comm
36.020			A1	Basaltic Clast	19180	260	260
36.255	36.24	36.27	S1	Solitary coral (in situ)	18620	220	210
41.830	36.25	47.41	D1	FO Thalassiosira praefraga complex	20300			(C6r)
54.960	54.94	54.98	S2	Bivalve fragment (provenance uncertain)	20350	380	420
54.960	54.94	54.98	S2	Bivalve fragment (provenance uncertain)	20290	640	550
112.500	111.00	114.00	A2	Pumice	21440	50	50
125.925	125.92	125.93	A3	Trachyte Clast	22560	290	290
126.555	126.55	126.56	S3	Pectinid fragment (provenance uncertain)	22240	390	390
144.440			Nf1	LO Dictycoccites bisectus	23900			(C6Cn.2r)
193.000			A4	Pumice	23980	130	130
194.890	194.87	194.91	S4	Bivalve (in situ)	24520	630	660
198.745	198.74	198.75	S5	Bivalve fragment (provenance uncertain)	24100	350	360
246.985	246.97	247.00	S6	Bivalve (in situ)	24020	350	350
247.690	247.67	247.71	S7	Bivalve fragment (provenance uncertain)	24810	340	340
248.140	236.26	260.02	D2	LO Lisitzinia ornata	24100			(C6Cr)
280.030			A5	Pumice	24220	60	60
294.220			A6	Trachyte Clast	24980	170	170
408.830	405.39	412.27	D3	LO Eurossia irregularis	27000			27 to 29 Ma (C9 - C10)
408.830	405.39	412.27	D4	LO Pyxilla reticulata	30100			(C11r)
412.250			Nf2	LO Chiasmolithus altus	26100			(C8)
439.610	437.37	441.85	D5	LO Rhizosolenia antarctica	29800			(C11n.2n)
442.880	441.87	443.89	D6	LO Rhizosolenia oligocaenica	29600			(C11n.1r)
444.430	443.90	444.96	D7	LO Asterolampra punctifera	27000			(C9n)
445.045	445.03	445.06	S8	Modiolid fragment (in situ)	29410	520	500
460.655	460.64	460.67	S9	Modiolid fragment (in situ)	29550	520	540
463.370	463.36	463.38	S10	Modiolid fragment (in situ)	29890	510	520
483.165	483.15	483.18	S11	Modiolid fragment (in situ)	30670	450	480
483.165	483.15	483.18	S11	Modiolid fragment (in situ)	30330	480	500
483.165	483.15	483.18	S11	Modiolid fragment (in situ)	30390	470	510
554.220	543.81	564.63	D8	FO Cavitatus jouseanus	30900			(C12n)
564.670			D9	CIROS-1 <Assemblage B> absent	<33000			(C13n)
564.670			D9	LO Hemiaulus characteristicus absent	<33000			(C13n)
624.150			MP1	<Transantarctic assemblage> absent				(<C13n to C15n)