Los Jagüeyes

Located on a distributary of the Rio Santa Maria, probably an earlier channel of the river, is a secondary source of marekanites that exhibits at least two source groups based on elemental composition. One of the source groups appears to be the Sierra Fresnal primary source which is actually located about 60 km north of Los Jagüeyes and not along the same drainage system, and actually downstream from Los Jagüeyes (see data in Appendix). Again, this is a typical pattern in northwest Mexico frustrating the accurate delineation of obsidian sources. Marekanites up to 50 mm in diameter are located on the lower pebble terrace that contains sub-rounded and rounded marekanites, chalcedony blossoms, and polychrome agate. The area exhibits stone tools including bipolar core fragments of obsidian and 10+ projectile points, many of which look similar to Cienega points and those recovered in Late Archaic/Early Agricultural sites in Chihuahua, Arizona and New Mexico in an area about 100 m in diameter (Hard and Roney 1999). No ceramics were noted. Metate fragments and a portable mortar were also present all produced from vesicular andesite. The density of geological marekanites was up to 1 per 50m2. It is impossible to determine which unreduced nodules were geological and which were cultural. It is possible that the Sierra Fresnal nodules were cultural. An examination of the surrounding hills, that included rhyolite domes, did not reveal any in-situ marekanites. This "source" is located at UTM 13R 0271137/3371028 on the INEGI Malpais H13A72 1:50,000 sheet.

 

Sample

Ti

Mn

Fe

Zn

Rb

Sr

Y

Zr

Nb

Ba

Ce

Pb

Th

091999-1-1

1432

846

25319

268

276

11

153

1443

121

24

324

58

33

091999-1-3

1484

815

25933

295

287

10

154

1466

134

0

426

57

22

091999-1-4

1446

638

29959

356

290

9

212

2006

170

13

374

60

40

091999-1-5

1431

920

26776

273

258

9

156

1648

131

4

413

65

32

091999-1-6

1457

890

25541

280

282

15

155

1494

133

22

341

64

40

091999-1-7

1906

1202

33731

352

296

15

166

1749

132

0

321

63

29

091999-1-8

1348

934

26306

282

267

13

156

1540

128

13

324

61

24

091999-1-9

1387

852

26863

288

279

13

151

1464

130

1

294

62

29

091999-1-10

1480

817

24623

254

260

11

151

1439

138

0

379

61

26

091999-1-11

1356

849

26119

320

283

15

144

1416

119

1

333

63

29

RGM1-S4

1548

286

13213

42

149

108

27

220

10

773

19

24

15

 


 

 

 

 

 

 

 

 

 

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Revised: 26 February 2020