Durham Basin text file

DURHAM AND SANFORD BASINS, NORTH CAROLINA

One hundred six (106) samples of diabase from eight (8) sheets and five (5) dikes were collected by Froelich and Gottfried and analyzed by the U.S. Geological Survey. All of the sheets and all but one of the dikes sampled in this study are representative of the olivine-normative magma type; the "JY" dike, however, is high Ti, quartz-nomative.

Platinum (Pt) and palladium (Pd) abundances and ratios in the chilled margins of the olivine-normative sheets and dikes are subequal (at about 10 ppb each), and characteristic of this magma type elsewhere in the province. In the olivine-rich cumulate zones of the Creedmoor and Butner sheets, Pd and Pt abundances and ratios remain similar and fairly constant; in the Nello Teer-North Durham and Oak Grove sheets, however, Pt consistently exceeds Pd, commonly two- to four-fold, in places by an order of magnitude (see DDH-NTQ-90, Table 3D, for example). Although no thick or extensive zones of anomalous enrichment were discovered, some of the highest abundances of Pt (to 55 ppb in DDH-NTQ90, Table 3D, and 62 ppb in DDH-A-93, Table 2C) and local enrichment of Pd (96 ppb in DDH-A-93, Table 2C) are present in local zones cored in the thick sheets at Nello Teer, North Durham and Butner.

Whereas the NTQ zone of enriched Pt is in cumulate rocks, the Butner anomaly zone is in a late-stage, coarsely crystalline pegmatoidal and granophyric segregation. As diabase outcrops are poor due to deep weathering, many prospective sheets and areas were not sampled during this reconnaissance study.

 

SAMPLE NO

MAGMA TYPE

DESCRIPTION OF SAMPLE 

F-84-WC-2

Olivine normative

Wilton sheet - Table I
Cumulate

FG-87-Db-24

Olivine normative (?)

Hester sheet - Table 1
Diabase, fine

FG-87-Db-24C

 

Diabase, altered

FG-87-Db-21

Olivine normative

Creedmoor sheet - Table I
Diabase

FG-87-Db-22

 

Cumulate

FG-87-Db-23

 

Diabase, coarse

DDH BUT-10'

Olivine normative

Butner sheet
USGS core hole BUT-1
Table 2a, 2b, 2c
Diabase

30'  

 

Cumulate  

50'  

 

 

 80'

 

 

100'  

 

 

 140'

 

 

170' 

 

 

190' 

 

 

220' 

 

 

250' 

 

 

270' 

 

 

300' 

 

 

330' 

 

 

350' 

 

 

 360'

 

 Diabase

 370'

 

Cumulate 

380' 

 

 

390' 

 

 

395' 

 

 

400' 

 

 

402' 

 

Diabase 

403' 

 

 

404' 

 

Lower chill 

DDH-BUT-404.5'

 

Lower chill

DDH-A-93'

 

Pegmatoid 

NTQ-1

Olivine diabase 

North Durham sheet
Nello Teer quarry (north face)
Table 3a
Diabase-aphyric

-2

 

 

-3

 

 

-4

 

 

-5

 

Upper chill margin 

NTQ-8

Olivine diabase 

(west face) Table 3b
Cumulate-gabbro/troctolite

-9

 

 

-10

 

 

-11

 

 

-12

 

 

-13

 

 

-14

 

Pegmatite 

-14A

 

 

DDH NTQ-7'

Olivine normative

North Durham sheet,
USGS core hole DDH-NTQ-1
Table 3c, 3d, 3e
Nello-Teer quarry
Diabase

-10, 

 

 Pegmatite

-17' 

 

Diabase 

-30' 

 

 

 -40'

 

 

 -501'

 

 

 -601'

 

 

-701' 

 

 

-80' 

 

Cumulate 

-90' 

 

 

 -100'

 

 

 -110'

 

 

-120' 

 

 

-130' 

 

 

-140' 

 

 

-150' 

 

 

-160' 

 

 

-170' 

 

 

-180' 

 

 

 -190'

 

 

-200' 

 

 

 -210'

 

 

 -211'

 

 

-212' 

 

Lower chilled margin 

DBF-85 -11

Olivine normative

North Durham sheet
Eno River Section
Table 3f, 3g
Pegmatoid

-12A 

 

Cumulate 

-12B 

 

(5 ft above 12A) 

-12C 

 

(3 ft above 12B) 

-12D 

 

(9 ft above 12C) 

 

 

 

DBF-85 -13A

Olivine normative

Cumulate

-13B 

 

(25 ft above 13A) 

 

 

 

DBF-85 -14

Olivine normative

Cumulate

 -15

 

 

-16 

 

Aphanitic chill 

-16A 

 

Diabase 

DBF-85 -17

Olivine normative

Table 5
Diabase dike

-17A 

 

 

BNC-85-1

Olivine normative

North Durham sheet
Braggtown quarry - Table 3h
Diabase

BNC-85-IA

 

 

DBF-85-10B

Olivine normative

North Durham sheet - Table 3h
Cumulate

DBF-85-18

Olivine normative

Ellerbe sheet - Table 3h
Diabase

DBF-85-19

 

 

DDH-1-90.5'

Olivine normative

Oak Grove sheet
Oak Grove core hole DDH-1 - Table 4a
Cumulate

1-97'

 

 

1-98'

 

 

1-99.5'

 

 

DDH-2-197'

Olivine normative

Oak Grove core hole DDH-2 - Table 4b
Cumulate

2-'201'

 

 

2-204'

 

 

2-205'

 

 

2-212'

 

 

2-218.3'

 

 

2-220'

 

 

2-223'

 

 

2-224'

 

 

NCMR3-257'

Olivine normative

Cumnock sheet, Sanford basin
core hole NCMR3 - Table 5
Diabase, upper chilled margin
(off 200 ft-thick sheet)

NCCMI-258'

Olivine normative

Sanfordbasin, core hole NCCM1 - Table 5
Diabase dike, chilled margin

DBF-85-17

Olivine normative

Durhambasin - Table 5
Diabase dike, float

DBF-85-17A

 

 

FG-87-DB-20

Olivine normative

Durhambasin - Table 5
Diabase dike

JY-l

High Ti, quartz normative

JY dike, Durham basin Table 5
Diabase dike

JY-2